Merge branch 'kmap_atomic' of git://github.com/congwang/linux
Linus Torvalds [Wed, 21 Mar 2012 16:40:26 +0000 (09:40 -0700)]
Pull kmap_atomic cleanup from Cong Wang.

It's been in -next for a long time, and it gets rid of the (no longer
used) second argument to k[un]map_atomic().

Fix up a few trivial conflicts in various drivers, and do an "evil
merge" to catch some new uses that have come in since Cong's tree.

* 'kmap_atomic' of git://github.com/congwang/linux: (59 commits)
  feature-removal-schedule.txt: schedule the deprecated form of kmap_atomic() for removal
  highmem: kill all __kmap_atomic() [swarren@nvidia.com: highmem: Fix ARM build break due to __kmap_atomic rename]
  drbd: remove the second argument of k[un]map_atomic()
  zcache: remove the second argument of k[un]map_atomic()
  gma500: remove the second argument of k[un]map_atomic()
  dm: remove the second argument of k[un]map_atomic()
  tomoyo: remove the second argument of k[un]map_atomic()
  sunrpc: remove the second argument of k[un]map_atomic()
  rds: remove the second argument of k[un]map_atomic()
  net: remove the second argument of k[un]map_atomic()
  mm: remove the second argument of k[un]map_atomic()
  lib: remove the second argument of k[un]map_atomic()
  power: remove the second argument of k[un]map_atomic()
  kdb: remove the second argument of k[un]map_atomic()
  udf: remove the second argument of k[un]map_atomic()
  ubifs: remove the second argument of k[un]map_atomic()
  squashfs: remove the second argument of k[un]map_atomic()
  reiserfs: remove the second argument of k[un]map_atomic()
  ocfs2: remove the second argument of k[un]map_atomic()
  ntfs: remove the second argument of k[un]map_atomic()
  ...

15 files changed:
1  2 
Documentation/feature-removal-schedule.txt
arch/x86/crypto/aesni-intel_glue.c
drivers/net/ethernet/intel/e1000/e1000_main.c
drivers/net/ethernet/intel/e1000e/netdev.c
drivers/net/ethernet/sun/cassini.c
drivers/scsi/fcoe/fcoe.c
drivers/scsi/storvsc_drv.c
drivers/staging/ramster/xvmalloc.c
drivers/staging/ramster/zcache-main.c
drivers/staging/zcache/zcache-main.c
drivers/staging/zram/zram_drv.c
fs/exec.c
fs/namei.c
net/rds/ib_recv.c
net/rds/iw_recv.c

@@@ -527,11 -527,8 +527,19 @@@ Who:     Nicolas Ferre <nicolas.ferre@atmel
  
  ----------------------------
  
 +What: Low Performance USB Block driver ("CONFIG_BLK_DEV_UB")
 +When: 3.6
 +Why:  This driver provides support for USB storage devices like "USB
 +      sticks". As of now, it is deactivated in Debian, Fedora and
 +        Ubuntu. All current users can switch over to usb-storage
 +        (CONFIG_USB_STORAGE) which only drawback is the additional SCSI
 +        stack.
 +Who:  Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
++
++----------------------------
++
+ What: kmap_atomic(page, km_type)
+ When: 3.5
+ Why:  The old kmap_atomic() with two arguments is deprecated, we only
+       keep it for backward compatibility for few cycles and then drop it.
+ Who:  Cong Wang <amwang@redhat.com>
Simple merge
@@@ -1274,51 -1253,43 +1274,50 @@@ static bool e1000_clean_rx_irq_ps(struc
                skb_put(skb, length);
  
                {
 -              /*
 -               * this looks ugly, but it seems compiler issues make it
 -               * more efficient than reusing j
 -               */
 -              int l1 = le16_to_cpu(rx_desc->wb.upper.length[0]);
 -
 -              /*
 -               * page alloc/put takes too long and effects small packet
 -               * throughput, so unsplit small packets and save the alloc/put
 -               * only valid in softirq (napi) context to call kmap_*
 -               */
 -              if (l1 && (l1 <= copybreak) &&
 -                  ((length + l1) <= adapter->rx_ps_bsize0)) {
 -                      u8 *vaddr;
 -
 -                      ps_page = &buffer_info->ps_pages[0];
 +                      /*
 +                       * this looks ugly, but it seems compiler issues make
 +                       * it more efficient than reusing j
 +                       */
 +                      int l1 = le16_to_cpu(rx_desc->wb.upper.length[0]);
  
                        /*
 -                       * there is no documentation about how to call
 -                       * kmap_atomic, so we can't hold the mapping
 -                       * very long
 +                       * page alloc/put takes too long and effects small
 +                       * packet throughput, so unsplit small packets and
 +                       * save the alloc/put only valid in softirq (napi)
 +                       * context to call kmap_*
                         */
 -                      dma_sync_single_for_cpu(&pdev->dev, ps_page->dma,
 -                                              PAGE_SIZE, DMA_FROM_DEVICE);
 -                      vaddr = kmap_atomic(ps_page->page);
 -                      memcpy(skb_tail_pointer(skb), vaddr, l1);
 -                      kunmap_atomic(vaddr);
 -                      dma_sync_single_for_device(&pdev->dev, ps_page->dma,
 -                                                 PAGE_SIZE, DMA_FROM_DEVICE);
 -
 -                      /* remove the CRC */
 -                      if (!(adapter->flags2 & FLAG2_CRC_STRIPPING))
 -                              l1 -= 4;
 -
 -                      skb_put(skb, l1);
 -                      goto copydone;
 -              } /* if */
 +                      if (l1 && (l1 <= copybreak) &&
 +                          ((length + l1) <= adapter->rx_ps_bsize0)) {
 +                              u8 *vaddr;
 +
 +                              ps_page = &buffer_info->ps_pages[0];
 +
 +                              /*
 +                               * there is no documentation about how to call
 +                               * kmap_atomic, so we can't hold the mapping
 +                               * very long
 +                               */
 +                              dma_sync_single_for_cpu(&pdev->dev,
 +                                                      ps_page->dma,
 +                                                      PAGE_SIZE,
 +                                                      DMA_FROM_DEVICE);
-                               vaddr = kmap_atomic(ps_page->page,
-                                                   KM_SKB_DATA_SOFTIRQ);
++                              vaddr = kmap_atomic(ps_page->page);
 +                              memcpy(skb_tail_pointer(skb), vaddr, l1);
-                               kunmap_atomic(vaddr, KM_SKB_DATA_SOFTIRQ);
++                              kunmap_atomic(vaddr);
 +                              dma_sync_single_for_device(&pdev->dev,
 +                                                         ps_page->dma,
 +                                                         PAGE_SIZE,
 +                                                         DMA_FROM_DEVICE);
 +
 +                              /* remove the CRC */
 +                              if (!(adapter->flags2 & FLAG2_CRC_STRIPPING)) {
 +                                      if (!(netdev->features & NETIF_F_RXFCS))
 +                                              l1 -= 4;
 +                              }
 +
 +                              skb_put(skb, l1);
 +                              goto copydone;
 +                      } /* if */
                }
  
                for (j = 0; j < PS_PAGE_BUFFERS; j++) {
Simple merge
Simple merge
@@@ -408,227 -398,6 +408,227 @@@ get_in_err
  
  }
  
 +static void destroy_bounce_buffer(struct scatterlist *sgl,
 +                                unsigned int sg_count)
 +{
 +      int i;
 +      struct page *page_buf;
 +
 +      for (i = 0; i < sg_count; i++) {
 +              page_buf = sg_page((&sgl[i]));
 +              if (page_buf != NULL)
 +                      __free_page(page_buf);
 +      }
 +
 +      kfree(sgl);
 +}
 +
 +static int do_bounce_buffer(struct scatterlist *sgl, unsigned int sg_count)
 +{
 +      int i;
 +
 +      /* No need to check */
 +      if (sg_count < 2)
 +              return -1;
 +
 +      /* We have at least 2 sg entries */
 +      for (i = 0; i < sg_count; i++) {
 +              if (i == 0) {
 +                      /* make sure 1st one does not have hole */
 +                      if (sgl[i].offset + sgl[i].length != PAGE_SIZE)
 +                              return i;
 +              } else if (i == sg_count - 1) {
 +                      /* make sure last one does not have hole */
 +                      if (sgl[i].offset != 0)
 +                              return i;
 +              } else {
 +                      /* make sure no hole in the middle */
 +                      if (sgl[i].length != PAGE_SIZE || sgl[i].offset != 0)
 +                              return i;
 +              }
 +      }
 +      return -1;
 +}
 +
 +static struct scatterlist *create_bounce_buffer(struct scatterlist *sgl,
 +                                              unsigned int sg_count,
 +                                              unsigned int len,
 +                                              int write)
 +{
 +      int i;
 +      int num_pages;
 +      struct scatterlist *bounce_sgl;
 +      struct page *page_buf;
 +      unsigned int buf_len = ((write == WRITE_TYPE) ? 0 : PAGE_SIZE);
 +
 +      num_pages = ALIGN(len, PAGE_SIZE) >> PAGE_SHIFT;
 +
 +      bounce_sgl = kcalloc(num_pages, sizeof(struct scatterlist), GFP_ATOMIC);
 +      if (!bounce_sgl)
 +              return NULL;
 +
 +      for (i = 0; i < num_pages; i++) {
 +              page_buf = alloc_page(GFP_ATOMIC);
 +              if (!page_buf)
 +                      goto cleanup;
 +              sg_set_page(&bounce_sgl[i], page_buf, buf_len, 0);
 +      }
 +
 +      return bounce_sgl;
 +
 +cleanup:
 +      destroy_bounce_buffer(bounce_sgl, num_pages);
 +      return NULL;
 +}
 +
++/* Disgusting wrapper functions */
++static inline unsigned long sg_kmap_atomic(struct scatterlist *sgl, int idx)
++{
++      void *addr = kmap_atomic(sg_page(sgl + idx));
++      return (unsigned long)addr;
++}
++
++static inline void sg_kunmap_atomic(unsigned long addr)
++{
++      kunmap_atomic((void *)addr);
++}
++
++
 +/* Assume the original sgl has enough room */
 +static unsigned int copy_from_bounce_buffer(struct scatterlist *orig_sgl,
 +                                          struct scatterlist *bounce_sgl,
 +                                          unsigned int orig_sgl_count,
 +                                          unsigned int bounce_sgl_count)
 +{
 +      int i;
 +      int j = 0;
 +      unsigned long src, dest;
 +      unsigned int srclen, destlen, copylen;
 +      unsigned int total_copied = 0;
 +      unsigned long bounce_addr = 0;
 +      unsigned long dest_addr = 0;
 +      unsigned long flags;
 +
 +      local_irq_save(flags);
 +
 +      for (i = 0; i < orig_sgl_count; i++) {
-               dest_addr = (unsigned long)kmap_atomic(sg_page((&orig_sgl[i])),
-                                       KM_IRQ0) + orig_sgl[i].offset;
++              dest_addr = sg_kmap_atomic(orig_sgl,i) + orig_sgl[i].offset;
 +              dest = dest_addr;
 +              destlen = orig_sgl[i].length;
 +
 +              if (bounce_addr == 0)
-                       bounce_addr =
-                       (unsigned long)kmap_atomic(sg_page((&bounce_sgl[j])),
-                                                       KM_IRQ0);
++                      bounce_addr = sg_kmap_atomic(bounce_sgl,j);
 +
 +              while (destlen) {
 +                      src = bounce_addr + bounce_sgl[j].offset;
 +                      srclen = bounce_sgl[j].length - bounce_sgl[j].offset;
 +
 +                      copylen = min(srclen, destlen);
 +                      memcpy((void *)dest, (void *)src, copylen);
 +
 +                      total_copied += copylen;
 +                      bounce_sgl[j].offset += copylen;
 +                      destlen -= copylen;
 +                      dest += copylen;
 +
 +                      if (bounce_sgl[j].offset == bounce_sgl[j].length) {
 +                              /* full */
-                               kunmap_atomic((void *)bounce_addr, KM_IRQ0);
++                              sg_kunmap_atomic(bounce_addr);
 +                              j++;
 +
 +                              /*
 +                               * It is possible that the number of elements
 +                               * in the bounce buffer may not be equal to
 +                               * the number of elements in the original
 +                               * scatter list. Handle this correctly.
 +                               */
 +
 +                              if (j == bounce_sgl_count) {
 +                                      /*
 +                                       * We are done; cleanup and return.
 +                                       */
-                                       kunmap_atomic((void *)(dest_addr -
-                                                       orig_sgl[i].offset),
-                                                       KM_IRQ0);
++                                      sg_kunmap_atomic(dest_addr - orig_sgl[i].offset);
 +                                      local_irq_restore(flags);
 +                                      return total_copied;
 +                              }
 +
 +                              /* if we need to use another bounce buffer */
 +                              if (destlen || i != orig_sgl_count - 1)
-                                       bounce_addr =
-                                       (unsigned long)kmap_atomic(
-                                       sg_page((&bounce_sgl[j])), KM_IRQ0);
++                                      bounce_addr = sg_kmap_atomic(bounce_sgl,j);
 +                      } else if (destlen == 0 && i == orig_sgl_count - 1) {
 +                              /* unmap the last bounce that is < PAGE_SIZE */
-                               kunmap_atomic((void *)bounce_addr, KM_IRQ0);
++                              sg_kunmap_atomic(bounce_addr);
 +                      }
 +              }
 +
-               kunmap_atomic((void *)(dest_addr - orig_sgl[i].offset),
-                             KM_IRQ0);
++              sg_kunmap_atomic(dest_addr - orig_sgl[i].offset);
 +      }
 +
 +      local_irq_restore(flags);
 +
 +      return total_copied;
 +}
 +
 +/* Assume the bounce_sgl has enough room ie using the create_bounce_buffer() */
 +static unsigned int copy_to_bounce_buffer(struct scatterlist *orig_sgl,
 +                                        struct scatterlist *bounce_sgl,
 +                                        unsigned int orig_sgl_count)
 +{
 +      int i;
 +      int j = 0;
 +      unsigned long src, dest;
 +      unsigned int srclen, destlen, copylen;
 +      unsigned int total_copied = 0;
 +      unsigned long bounce_addr = 0;
 +      unsigned long src_addr = 0;
 +      unsigned long flags;
 +
 +      local_irq_save(flags);
 +
 +      for (i = 0; i < orig_sgl_count; i++) {
-               src_addr = (unsigned long)kmap_atomic(sg_page((&orig_sgl[i])),
-                               KM_IRQ0) + orig_sgl[i].offset;
++              src_addr = sg_kmap_atomic(orig_sgl,i) + orig_sgl[i].offset;
 +              src = src_addr;
 +              srclen = orig_sgl[i].length;
 +
 +              if (bounce_addr == 0)
-                       bounce_addr =
-                       (unsigned long)kmap_atomic(sg_page((&bounce_sgl[j])),
-                                               KM_IRQ0);
++                      bounce_addr = sg_kmap_atomic(bounce_sgl,j);
 +
 +              while (srclen) {
 +                      /* assume bounce offset always == 0 */
 +                      dest = bounce_addr + bounce_sgl[j].length;
 +                      destlen = PAGE_SIZE - bounce_sgl[j].length;
 +
 +                      copylen = min(srclen, destlen);
 +                      memcpy((void *)dest, (void *)src, copylen);
 +
 +                      total_copied += copylen;
 +                      bounce_sgl[j].length += copylen;
 +                      srclen -= copylen;
 +                      src += copylen;
 +
 +                      if (bounce_sgl[j].length == PAGE_SIZE) {
 +                              /* full..move to next entry */
-                               kunmap_atomic((void *)bounce_addr, KM_IRQ0);
++                              sg_kunmap_atomic(bounce_addr);
 +                              j++;
 +
 +                              /* if we need to use another bounce buffer */
 +                              if (srclen || i != orig_sgl_count - 1)
-                                       bounce_addr =
-                                       (unsigned long)kmap_atomic(
-                                       sg_page((&bounce_sgl[j])), KM_IRQ0);
++                                      bounce_addr = sg_kmap_atomic(bounce_sgl,j);
 +
 +                      } else if (srclen == 0 && i == orig_sgl_count - 1) {
 +                              /* unmap the last bounce that is < PAGE_SIZE */
-                               kunmap_atomic((void *)bounce_addr, KM_IRQ0);
++                              sg_kunmap_atomic(bounce_addr);
 +                      }
 +              }
 +
-               kunmap_atomic((void *)(src_addr - orig_sgl[i].offset), KM_IRQ0);
++              sg_kunmap_atomic(src_addr - orig_sgl[i].offset);
 +      }
 +
 +      local_irq_restore(flags);
 +
 +      return total_copied;
 +}
 +
  static int storvsc_channel_init(struct hv_device *device)
  {
        struct storvsc_device *stor_device;
Simple merge
index 36d53ed,0000000..68b2e05
mode 100644,000000..100644
--- /dev/null
@@@ -1,3320 -1,0 +1,3320 @@@
 +/*
 + * zcache.c
 + *
 + * Copyright (c) 2010-2012, Dan Magenheimer, Oracle Corp.
 + * Copyright (c) 2010,2011, Nitin Gupta
 + *
 + * Zcache provides an in-kernel "host implementation" for transcendent memory
 + * and, thus indirectly, for cleancache and frontswap.  Zcache includes two
 + * page-accessible memory [1] interfaces, both utilizing lzo1x compression:
 + * 1) "compression buddies" ("zbud") is used for ephemeral pages
 + * 2) xvmalloc is used for persistent pages.
 + * Xvmalloc (based on the TLSF allocator) has very low fragmentation
 + * so maximizes space efficiency, while zbud allows pairs (and potentially,
 + * in the future, more than a pair of) compressed pages to be closely linked
 + * so that reclaiming can be done via the kernel's physical-page-oriented
 + * "shrinker" interface.
 + *
 + * [1] For a definition of page-accessible memory (aka PAM), see:
 + *   http://marc.info/?l=linux-mm&m=127811271605009
 + *  RAMSTER TODO:
 + *   - handle remotifying of buddied pages (see zbud_remotify_zbpg)
 + *   - kernel boot params: nocleancache/nofrontswap don't always work?!?
 + */
 +
 +#include <linux/module.h>
 +#include <linux/cpu.h>
 +#include <linux/highmem.h>
 +#include <linux/list.h>
 +#include <linux/lzo.h>
 +#include <linux/slab.h>
 +#include <linux/spinlock.h>
 +#include <linux/types.h>
 +#include <linux/atomic.h>
 +#include <linux/math64.h>
 +#include "tmem.h"
 +#include "zcache.h"
 +#include "ramster.h"
 +#include "cluster/tcp.h"
 +
 +#include "xvmalloc.h" /* temporary until change to zsmalloc */
 +
 +#define       RAMSTER_TESTING
 +
 +#if (!defined(CONFIG_CLEANCACHE) && !defined(CONFIG_FRONTSWAP))
 +#error "ramster is useless without CONFIG_CLEANCACHE or CONFIG_FRONTSWAP"
 +#endif
 +#ifdef CONFIG_CLEANCACHE
 +#include <linux/cleancache.h>
 +#endif
 +#ifdef CONFIG_FRONTSWAP
 +#include <linux/frontswap.h>
 +#endif
 +
 +enum ramster_remotify_op {
 +      RAMSTER_REMOTIFY_EPH_PUT,
 +      RAMSTER_REMOTIFY_PERS_PUT,
 +      RAMSTER_REMOTIFY_FLUSH_PAGE,
 +      RAMSTER_REMOTIFY_FLUSH_OBJ,
 +      RAMSTER_INTRANSIT_PERS
 +};
 +
 +struct ramster_remotify_hdr {
 +      enum ramster_remotify_op op;
 +      struct list_head list;
 +};
 +
 +#define ZBH_SENTINEL  0x43214321
 +#define ZBPG_SENTINEL  0xdeadbeef
 +
 +#define ZBUD_MAX_BUDS 2
 +
 +struct zbud_hdr {
 +      struct ramster_remotify_hdr rem_op;
 +      uint16_t client_id;
 +      uint16_t pool_id;
 +      struct tmem_oid oid;
 +      uint32_t index;
 +      uint16_t size; /* compressed size in bytes, zero means unused */
 +      DECL_SENTINEL
 +};
 +
 +#define ZVH_SENTINEL  0x43214321
 +static const int zv_max_page_size = (PAGE_SIZE / 8) * 7;
 +
 +struct zv_hdr {
 +      struct ramster_remotify_hdr rem_op;
 +      uint16_t client_id;
 +      uint16_t pool_id;
 +      struct tmem_oid oid;
 +      uint32_t index;
 +      DECL_SENTINEL
 +};
 +
 +struct flushlist_node {
 +      struct ramster_remotify_hdr rem_op;
 +      struct tmem_xhandle xh;
 +};
 +
 +union {
 +      struct ramster_remotify_hdr rem_op;
 +      struct zv_hdr zv;
 +      struct zbud_hdr zbud;
 +      struct flushlist_node flist;
 +} remotify_list_node;
 +
 +static LIST_HEAD(zcache_rem_op_list);
 +static DEFINE_SPINLOCK(zcache_rem_op_list_lock);
 +
 +#if 0
 +/* this is more aggressive but may cause other problems? */
 +#define ZCACHE_GFP_MASK       (GFP_ATOMIC | __GFP_NORETRY | __GFP_NOWARN)
 +#else
 +#define ZCACHE_GFP_MASK \
 +      (__GFP_FS | __GFP_NORETRY | __GFP_NOWARN | __GFP_NOMEMALLOC)
 +#endif
 +
 +#define MAX_POOLS_PER_CLIENT 16
 +
 +#define MAX_CLIENTS 16
 +#define LOCAL_CLIENT ((uint16_t)-1)
 +
 +MODULE_LICENSE("GPL");
 +
 +struct zcache_client {
 +      struct tmem_pool *tmem_pools[MAX_POOLS_PER_CLIENT];
 +      struct xv_pool *xvpool;
 +      bool allocated;
 +      atomic_t refcount;
 +};
 +
 +static struct zcache_client zcache_host;
 +static struct zcache_client zcache_clients[MAX_CLIENTS];
 +
 +static inline uint16_t get_client_id_from_client(struct zcache_client *cli)
 +{
 +      BUG_ON(cli == NULL);
 +      if (cli == &zcache_host)
 +              return LOCAL_CLIENT;
 +      return cli - &zcache_clients[0];
 +}
 +
 +static inline bool is_local_client(struct zcache_client *cli)
 +{
 +      return cli == &zcache_host;
 +}
 +
 +/**********
 + * Compression buddies ("zbud") provides for packing two (or, possibly
 + * in the future, more) compressed ephemeral pages into a single "raw"
 + * (physical) page and tracking them with data structures so that
 + * the raw pages can be easily reclaimed.
 + *
 + * A zbud page ("zbpg") is an aligned page containing a list_head,
 + * a lock, and two "zbud headers".  The remainder of the physical
 + * page is divided up into aligned 64-byte "chunks" which contain
 + * the compressed data for zero, one, or two zbuds.  Each zbpg
 + * resides on: (1) an "unused list" if it has no zbuds; (2) a
 + * "buddied" list if it is fully populated  with two zbuds; or
 + * (3) one of PAGE_SIZE/64 "unbuddied" lists indexed by how many chunks
 + * the one unbuddied zbud uses.  The data inside a zbpg cannot be
 + * read or written unless the zbpg's lock is held.
 + */
 +
 +struct zbud_page {
 +      struct list_head bud_list;
 +      spinlock_t lock;
 +      struct zbud_hdr buddy[ZBUD_MAX_BUDS];
 +      DECL_SENTINEL
 +      /* followed by NUM_CHUNK aligned CHUNK_SIZE-byte chunks */
 +};
 +
 +#define CHUNK_SHIFT   6
 +#define CHUNK_SIZE    (1 << CHUNK_SHIFT)
 +#define CHUNK_MASK    (~(CHUNK_SIZE-1))
 +#define NCHUNKS               (((PAGE_SIZE - sizeof(struct zbud_page)) & \
 +                              CHUNK_MASK) >> CHUNK_SHIFT)
 +#define MAX_CHUNK     (NCHUNKS-1)
 +
 +static struct {
 +      struct list_head list;
 +      unsigned count;
 +} zbud_unbuddied[NCHUNKS];
 +/* list N contains pages with N chunks USED and NCHUNKS-N unused */
 +/* element 0 is never used but optimizing that isn't worth it */
 +static unsigned long zbud_cumul_chunk_counts[NCHUNKS];
 +
 +struct list_head zbud_buddied_list;
 +static unsigned long zcache_zbud_buddied_count;
 +
 +/* protects the buddied list and all unbuddied lists */
 +static DEFINE_SPINLOCK(zbud_budlists_spinlock);
 +
 +static atomic_t zcache_zbud_curr_raw_pages;
 +static atomic_t zcache_zbud_curr_zpages;
 +static unsigned long zcache_zbud_curr_zbytes;
 +static unsigned long zcache_zbud_cumul_zpages;
 +static unsigned long zcache_zbud_cumul_zbytes;
 +static unsigned long zcache_compress_poor;
 +static unsigned long zcache_policy_percent_exceeded;
 +static unsigned long zcache_mean_compress_poor;
 +
 +/*
 + * RAMster counters
 + * - Remote pages are pages with a local pampd but the data is remote
 + * - Foreign pages are pages stored locally but belonging to another node
 + */
 +static atomic_t ramster_remote_pers_pages = ATOMIC_INIT(0);
 +static unsigned long ramster_pers_remotify_enable;
 +static unsigned long ramster_eph_remotify_enable;
 +static unsigned long ramster_eph_pages_remoted;
 +static unsigned long ramster_eph_pages_remote_failed;
 +static unsigned long ramster_pers_pages_remoted;
 +static unsigned long ramster_pers_pages_remote_failed;
 +static unsigned long ramster_pers_pages_remote_nomem;
 +static unsigned long ramster_remote_objects_flushed;
 +static unsigned long ramster_remote_object_flushes_failed;
 +static unsigned long ramster_remote_pages_flushed;
 +static unsigned long ramster_remote_page_flushes_failed;
 +static unsigned long ramster_remote_eph_pages_succ_get;
 +static unsigned long ramster_remote_pers_pages_succ_get;
 +static unsigned long ramster_remote_eph_pages_unsucc_get;
 +static unsigned long ramster_remote_pers_pages_unsucc_get;
 +static atomic_t ramster_curr_flnode_count = ATOMIC_INIT(0);
 +static unsigned long ramster_curr_flnode_count_max;
 +static atomic_t ramster_foreign_eph_pampd_count = ATOMIC_INIT(0);
 +static unsigned long ramster_foreign_eph_pampd_count_max;
 +static atomic_t ramster_foreign_pers_pampd_count = ATOMIC_INIT(0);
 +static unsigned long ramster_foreign_pers_pampd_count_max;
 +
 +/* forward references */
 +static void *zcache_get_free_page(void);
 +static void zcache_free_page(void *p);
 +
 +/*
 + * zbud helper functions
 + */
 +
 +static inline unsigned zbud_max_buddy_size(void)
 +{
 +      return MAX_CHUNK << CHUNK_SHIFT;
 +}
 +
 +static inline unsigned zbud_size_to_chunks(unsigned size)
 +{
 +      BUG_ON(size == 0 || size > zbud_max_buddy_size());
 +      return (size + CHUNK_SIZE - 1) >> CHUNK_SHIFT;
 +}
 +
 +static inline int zbud_budnum(struct zbud_hdr *zh)
 +{
 +      unsigned offset = (unsigned long)zh & (PAGE_SIZE - 1);
 +      struct zbud_page *zbpg = NULL;
 +      unsigned budnum = -1U;
 +      int i;
 +
 +      for (i = 0; i < ZBUD_MAX_BUDS; i++)
 +              if (offset == offsetof(typeof(*zbpg), buddy[i])) {
 +                      budnum = i;
 +                      break;
 +              }
 +      BUG_ON(budnum == -1U);
 +      return budnum;
 +}
 +
 +static char *zbud_data(struct zbud_hdr *zh, unsigned size)
 +{
 +      struct zbud_page *zbpg;
 +      char *p;
 +      unsigned budnum;
 +
 +      ASSERT_SENTINEL(zh, ZBH);
 +      budnum = zbud_budnum(zh);
 +      BUG_ON(size == 0 || size > zbud_max_buddy_size());
 +      zbpg = container_of(zh, struct zbud_page, buddy[budnum]);
 +      ASSERT_SPINLOCK(&zbpg->lock);
 +      p = (char *)zbpg;
 +      if (budnum == 0)
 +              p += ((sizeof(struct zbud_page) + CHUNK_SIZE - 1) &
 +                                                      CHUNK_MASK);
 +      else if (budnum == 1)
 +              p += PAGE_SIZE - ((size + CHUNK_SIZE - 1) & CHUNK_MASK);
 +      return p;
 +}
 +
 +static void zbud_copy_from_pampd(char *data, size_t *size, struct zbud_hdr *zh)
 +{
 +      struct zbud_page *zbpg;
 +      char *p;
 +      unsigned budnum;
 +
 +      ASSERT_SENTINEL(zh, ZBH);
 +      budnum = zbud_budnum(zh);
 +      zbpg = container_of(zh, struct zbud_page, buddy[budnum]);
 +      spin_lock(&zbpg->lock);
 +      BUG_ON(zh->size > *size);
 +      p = (char *)zbpg;
 +      if (budnum == 0)
 +              p += ((sizeof(struct zbud_page) + CHUNK_SIZE - 1) &
 +                                                      CHUNK_MASK);
 +      else if (budnum == 1)
 +              p += PAGE_SIZE - ((zh->size + CHUNK_SIZE - 1) & CHUNK_MASK);
 +      /* client should be filled in by caller */
 +      memcpy(data, p, zh->size);
 +      *size = zh->size;
 +      spin_unlock(&zbpg->lock);
 +}
 +
 +/*
 + * zbud raw page management
 + */
 +
 +static struct zbud_page *zbud_alloc_raw_page(void)
 +{
 +      struct zbud_page *zbpg = NULL;
 +      struct zbud_hdr *zh0, *zh1;
 +              zbpg = zcache_get_free_page();
 +      if (likely(zbpg != NULL)) {
 +              INIT_LIST_HEAD(&zbpg->bud_list);
 +              zh0 = &zbpg->buddy[0]; zh1 = &zbpg->buddy[1];
 +              spin_lock_init(&zbpg->lock);
 +              atomic_inc(&zcache_zbud_curr_raw_pages);
 +              INIT_LIST_HEAD(&zbpg->bud_list);
 +              SET_SENTINEL(zbpg, ZBPG);
 +              zh0->size = 0; zh1->size = 0;
 +              tmem_oid_set_invalid(&zh0->oid);
 +              tmem_oid_set_invalid(&zh1->oid);
 +      }
 +      return zbpg;
 +}
 +
 +static void zbud_free_raw_page(struct zbud_page *zbpg)
 +{
 +      struct zbud_hdr *zh0 = &zbpg->buddy[0], *zh1 = &zbpg->buddy[1];
 +
 +      ASSERT_SENTINEL(zbpg, ZBPG);
 +      BUG_ON(!list_empty(&zbpg->bud_list));
 +      ASSERT_SPINLOCK(&zbpg->lock);
 +      BUG_ON(zh0->size != 0 || tmem_oid_valid(&zh0->oid));
 +      BUG_ON(zh1->size != 0 || tmem_oid_valid(&zh1->oid));
 +      INVERT_SENTINEL(zbpg, ZBPG);
 +      spin_unlock(&zbpg->lock);
 +      atomic_dec(&zcache_zbud_curr_raw_pages);
 +      zcache_free_page(zbpg);
 +}
 +
 +/*
 + * core zbud handling routines
 + */
 +
 +static unsigned zbud_free(struct zbud_hdr *zh)
 +{
 +      unsigned size;
 +
 +      ASSERT_SENTINEL(zh, ZBH);
 +      BUG_ON(!tmem_oid_valid(&zh->oid));
 +      size = zh->size;
 +      BUG_ON(zh->size == 0 || zh->size > zbud_max_buddy_size());
 +      zh->size = 0;
 +      tmem_oid_set_invalid(&zh->oid);
 +      INVERT_SENTINEL(zh, ZBH);
 +      zcache_zbud_curr_zbytes -= size;
 +      atomic_dec(&zcache_zbud_curr_zpages);
 +      return size;
 +}
 +
 +static void zbud_free_and_delist(struct zbud_hdr *zh)
 +{
 +      unsigned chunks;
 +      struct zbud_hdr *zh_other;
 +      unsigned budnum = zbud_budnum(zh), size;
 +      struct zbud_page *zbpg =
 +              container_of(zh, struct zbud_page, buddy[budnum]);
 +
 +      /* FIXME, should be BUG_ON, pool destruction path doesn't disable
 +       * interrupts tmem_destroy_pool()->tmem_pampd_destroy_all_in_obj()->
 +       * tmem_objnode_node_destroy()-> zcache_pampd_free() */
 +      WARN_ON(!irqs_disabled());
 +      spin_lock(&zbpg->lock);
 +      if (list_empty(&zbpg->bud_list)) {
 +              /* ignore zombie page... see zbud_evict_pages() */
 +              spin_unlock(&zbpg->lock);
 +              return;
 +      }
 +      size = zbud_free(zh);
 +      ASSERT_SPINLOCK(&zbpg->lock);
 +      zh_other = &zbpg->buddy[(budnum == 0) ? 1 : 0];
 +      if (zh_other->size == 0) { /* was unbuddied: unlist and free */
 +              chunks = zbud_size_to_chunks(size) ;
 +              spin_lock(&zbud_budlists_spinlock);
 +              BUG_ON(list_empty(&zbud_unbuddied[chunks].list));
 +              list_del_init(&zbpg->bud_list);
 +              zbud_unbuddied[chunks].count--;
 +              spin_unlock(&zbud_budlists_spinlock);
 +              zbud_free_raw_page(zbpg);
 +      } else { /* was buddied: move remaining buddy to unbuddied list */
 +              chunks = zbud_size_to_chunks(zh_other->size) ;
 +              spin_lock(&zbud_budlists_spinlock);
 +              list_del_init(&zbpg->bud_list);
 +              zcache_zbud_buddied_count--;
 +              list_add_tail(&zbpg->bud_list, &zbud_unbuddied[chunks].list);
 +              zbud_unbuddied[chunks].count++;
 +              spin_unlock(&zbud_budlists_spinlock);
 +              spin_unlock(&zbpg->lock);
 +      }
 +}
 +
 +static struct zbud_hdr *zbud_create(uint16_t client_id, uint16_t pool_id,
 +                                      struct tmem_oid *oid,
 +                                      uint32_t index, struct page *page,
 +                                      void *cdata, unsigned size)
 +{
 +      struct zbud_hdr *zh0, *zh1, *zh = NULL;
 +      struct zbud_page *zbpg = NULL, *ztmp;
 +      unsigned nchunks;
 +      char *to;
 +      int i, found_good_buddy = 0;
 +
 +      nchunks = zbud_size_to_chunks(size) ;
 +      for (i = MAX_CHUNK - nchunks + 1; i > 0; i--) {
 +              spin_lock(&zbud_budlists_spinlock);
 +              if (!list_empty(&zbud_unbuddied[i].list)) {
 +                      list_for_each_entry_safe(zbpg, ztmp,
 +                                  &zbud_unbuddied[i].list, bud_list) {
 +                              if (spin_trylock(&zbpg->lock)) {
 +                                      found_good_buddy = i;
 +                                      goto found_unbuddied;
 +                              }
 +                      }
 +              }
 +              spin_unlock(&zbud_budlists_spinlock);
 +      }
 +      /* didn't find a good buddy, try allocating a new page */
 +      zbpg = zbud_alloc_raw_page();
 +      if (unlikely(zbpg == NULL))
 +              goto out;
 +      /* ok, have a page, now compress the data before taking locks */
 +      spin_lock(&zbud_budlists_spinlock);
 +      spin_lock(&zbpg->lock);
 +      list_add_tail(&zbpg->bud_list, &zbud_unbuddied[nchunks].list);
 +      zbud_unbuddied[nchunks].count++;
 +      zh = &zbpg->buddy[0];
 +      goto init_zh;
 +
 +found_unbuddied:
 +      ASSERT_SPINLOCK(&zbpg->lock);
 +      zh0 = &zbpg->buddy[0]; zh1 = &zbpg->buddy[1];
 +      BUG_ON(!((zh0->size == 0) ^ (zh1->size == 0)));
 +      if (zh0->size != 0) { /* buddy0 in use, buddy1 is vacant */
 +              ASSERT_SENTINEL(zh0, ZBH);
 +              zh = zh1;
 +      } else if (zh1->size != 0) { /* buddy1 in use, buddy0 is vacant */
 +              ASSERT_SENTINEL(zh1, ZBH);
 +              zh = zh0;
 +      } else
 +              BUG();
 +      list_del_init(&zbpg->bud_list);
 +      zbud_unbuddied[found_good_buddy].count--;
 +      list_add_tail(&zbpg->bud_list, &zbud_buddied_list);
 +      zcache_zbud_buddied_count++;
 +
 +init_zh:
 +      SET_SENTINEL(zh, ZBH);
 +      zh->size = size;
 +      zh->index = index;
 +      zh->oid = *oid;
 +      zh->pool_id = pool_id;
 +      zh->client_id = client_id;
 +      to = zbud_data(zh, size);
 +      memcpy(to, cdata, size);
 +      spin_unlock(&zbpg->lock);
 +      spin_unlock(&zbud_budlists_spinlock);
 +      zbud_cumul_chunk_counts[nchunks]++;
 +      atomic_inc(&zcache_zbud_curr_zpages);
 +      zcache_zbud_cumul_zpages++;
 +      zcache_zbud_curr_zbytes += size;
 +      zcache_zbud_cumul_zbytes += size;
 +out:
 +      return zh;
 +}
 +
 +static int zbud_decompress(struct page *page, struct zbud_hdr *zh)
 +{
 +      struct zbud_page *zbpg;
 +      unsigned budnum = zbud_budnum(zh);
 +      size_t out_len = PAGE_SIZE;
 +      char *to_va, *from_va;
 +      unsigned size;
 +      int ret = 0;
 +
 +      zbpg = container_of(zh, struct zbud_page, buddy[budnum]);
 +      spin_lock(&zbpg->lock);
 +      if (list_empty(&zbpg->bud_list)) {
 +              /* ignore zombie page... see zbud_evict_pages() */
 +              ret = -EINVAL;
 +              goto out;
 +      }
 +      ASSERT_SENTINEL(zh, ZBH);
 +      BUG_ON(zh->size == 0 || zh->size > zbud_max_buddy_size());
-       to_va = kmap_atomic(page, KM_USER0);
++      to_va = kmap_atomic(page);
 +      size = zh->size;
 +      from_va = zbud_data(zh, size);
 +      ret = lzo1x_decompress_safe(from_va, size, to_va, &out_len);
 +      BUG_ON(ret != LZO_E_OK);
 +      BUG_ON(out_len != PAGE_SIZE);
-       kunmap_atomic(to_va, KM_USER0);
++      kunmap_atomic(to_va);
 +out:
 +      spin_unlock(&zbpg->lock);
 +      return ret;
 +}
 +
 +/*
 + * The following routines handle shrinking of ephemeral pages by evicting
 + * pages "least valuable" first.
 + */
 +
 +static unsigned long zcache_evicted_raw_pages;
 +static unsigned long zcache_evicted_buddied_pages;
 +static unsigned long zcache_evicted_unbuddied_pages;
 +
 +static struct tmem_pool *zcache_get_pool_by_id(uint16_t cli_id,
 +                                              uint16_t poolid);
 +static void zcache_put_pool(struct tmem_pool *pool);
 +
 +/*
 + * Flush and free all zbuds in a zbpg, then free the pageframe
 + */
 +static void zbud_evict_zbpg(struct zbud_page *zbpg)
 +{
 +      struct zbud_hdr *zh;
 +      int i, j;
 +      uint32_t pool_id[ZBUD_MAX_BUDS], client_id[ZBUD_MAX_BUDS];
 +      uint32_t index[ZBUD_MAX_BUDS];
 +      struct tmem_oid oid[ZBUD_MAX_BUDS];
 +      struct tmem_pool *pool;
 +      unsigned long flags;
 +
 +      ASSERT_SPINLOCK(&zbpg->lock);
 +      for (i = 0, j = 0; i < ZBUD_MAX_BUDS; i++) {
 +              zh = &zbpg->buddy[i];
 +              if (zh->size) {
 +                      client_id[j] = zh->client_id;
 +                      pool_id[j] = zh->pool_id;
 +                      oid[j] = zh->oid;
 +                      index[j] = zh->index;
 +                      j++;
 +              }
 +      }
 +      spin_unlock(&zbpg->lock);
 +      for (i = 0; i < j; i++) {
 +              pool = zcache_get_pool_by_id(client_id[i], pool_id[i]);
 +              BUG_ON(pool == NULL);
 +              local_irq_save(flags);
 +              /* these flushes should dispose of any local storage */
 +              tmem_flush_page(pool, &oid[i], index[i]);
 +              local_irq_restore(flags);
 +              zcache_put_pool(pool);
 +      }
 +}
 +
 +/*
 + * Free nr pages.  This code is funky because we want to hold the locks
 + * protecting various lists for as short a time as possible, and in some
 + * circumstances the list may change asynchronously when the list lock is
 + * not held.  In some cases we also trylock not only to avoid waiting on a
 + * page in use by another cpu, but also to avoid potential deadlock due to
 + * lock inversion.
 + */
 +static void zbud_evict_pages(int nr)
 +{
 +      struct zbud_page *zbpg;
 +      int i, newly_unused_pages = 0;
 +
 +
 +      /* now try freeing unbuddied pages, starting with least space avail */
 +      for (i = 0; i < MAX_CHUNK; i++) {
 +retry_unbud_list_i:
 +              spin_lock_bh(&zbud_budlists_spinlock);
 +              if (list_empty(&zbud_unbuddied[i].list)) {
 +                      spin_unlock_bh(&zbud_budlists_spinlock);
 +                      continue;
 +              }
 +              list_for_each_entry(zbpg, &zbud_unbuddied[i].list, bud_list) {
 +                      if (unlikely(!spin_trylock(&zbpg->lock)))
 +                              continue;
 +                      zbud_unbuddied[i].count--;
 +                      spin_unlock(&zbud_budlists_spinlock);
 +                      zcache_evicted_unbuddied_pages++;
 +                      /* want budlists unlocked when doing zbpg eviction */
 +                      zbud_evict_zbpg(zbpg);
 +                      newly_unused_pages++;
 +                      local_bh_enable();
 +                      if (--nr <= 0)
 +                              goto evict_unused;
 +                      goto retry_unbud_list_i;
 +              }
 +              spin_unlock_bh(&zbud_budlists_spinlock);
 +      }
 +
 +      /* as a last resort, free buddied pages */
 +retry_bud_list:
 +      spin_lock_bh(&zbud_budlists_spinlock);
 +      if (list_empty(&zbud_buddied_list)) {
 +              spin_unlock_bh(&zbud_budlists_spinlock);
 +              goto evict_unused;
 +      }
 +      list_for_each_entry(zbpg, &zbud_buddied_list, bud_list) {
 +              if (unlikely(!spin_trylock(&zbpg->lock)))
 +                      continue;
 +              zcache_zbud_buddied_count--;
 +              spin_unlock(&zbud_budlists_spinlock);
 +              zcache_evicted_buddied_pages++;
 +              /* want budlists unlocked when doing zbpg eviction */
 +              zbud_evict_zbpg(zbpg);
 +              newly_unused_pages++;
 +              local_bh_enable();
 +              if (--nr <= 0)
 +                      goto evict_unused;
 +              goto retry_bud_list;
 +      }
 +      spin_unlock_bh(&zbud_budlists_spinlock);
 +
 +evict_unused:
 +      return;
 +}
 +
 +static DEFINE_PER_CPU(unsigned char *, zcache_remoteputmem);
 +
 +static int zbud_remotify_zbud(struct tmem_xhandle *xh, char *data,
 +                              size_t size)
 +{
 +      struct tmem_pool *pool;
 +      int i, remotenode, ret = -1;
 +      unsigned char cksum, *p;
 +      unsigned long flags;
 +
 +      for (p = data, cksum = 0, i = 0; i < size; i++)
 +              cksum += *p;
 +      ret = ramster_remote_put(xh, data, size, true, &remotenode);
 +      if (ret == 0) {
 +              /* data was successfully remoted so change the local version
 +               * to point to the remote node where it landed */
 +              pool = zcache_get_pool_by_id(LOCAL_CLIENT, xh->pool_id);
 +              BUG_ON(pool == NULL);
 +              local_irq_save(flags);
 +              /* tmem_replace will also free up any local space */
 +              (void)tmem_replace(pool, &xh->oid, xh->index,
 +                      pampd_make_remote(remotenode, size, cksum));
 +              local_irq_restore(flags);
 +              zcache_put_pool(pool);
 +              ramster_eph_pages_remoted++;
 +              ret = 0;
 +      } else
 +              ramster_eph_pages_remote_failed++;
 +      return ret;
 +}
 +
 +static int zbud_remotify_zbpg(struct zbud_page *zbpg)
 +{
 +      struct zbud_hdr *zh1, *zh2 = NULL;
 +      struct tmem_xhandle xh1, xh2 = { 0 };
 +      char *data1 = NULL, *data2 = NULL;
 +      size_t size1 = 0, size2 = 0;
 +      int ret = 0;
 +      unsigned char *tmpmem = __get_cpu_var(zcache_remoteputmem);
 +
 +      ASSERT_SPINLOCK(&zbpg->lock);
 +      if (zbpg->buddy[0].size == 0)
 +              zh1 = &zbpg->buddy[1];
 +      else if (zbpg->buddy[1].size == 0)
 +              zh1 = &zbpg->buddy[0];
 +      else {
 +              zh1 = &zbpg->buddy[0];
 +              zh2 = &zbpg->buddy[1];
 +      }
 +      /* don't remotify pages that are already remotified */
 +      if (zh1->client_id != LOCAL_CLIENT)
 +              zh1 = NULL;
 +      if ((zh2 != NULL) && (zh2->client_id != LOCAL_CLIENT))
 +              zh2 = NULL;
 +
 +      /* copy the data and metadata so can release lock */
 +      if (zh1 != NULL) {
 +              xh1.client_id = zh1->client_id;
 +              xh1.pool_id = zh1->pool_id;
 +              xh1.oid = zh1->oid;
 +              xh1.index = zh1->index;
 +              size1 = zh1->size;
 +              data1 = zbud_data(zh1, size1);
 +              memcpy(tmpmem, zbud_data(zh1, size1), size1);
 +              data1 = tmpmem;
 +              tmpmem += size1;
 +      }
 +      if (zh2 != NULL) {
 +              xh2.client_id = zh2->client_id;
 +              xh2.pool_id = zh2->pool_id;
 +              xh2.oid = zh2->oid;
 +              xh2.index = zh2->index;
 +              size2 = zh2->size;
 +              memcpy(tmpmem, zbud_data(zh2, size2), size2);
 +              data2 = tmpmem;
 +      }
 +      spin_unlock(&zbpg->lock);
 +      preempt_enable();
 +
 +      /* OK, no locks held anymore, remotify one or both zbuds */
 +      if (zh1 != NULL)
 +              ret = zbud_remotify_zbud(&xh1, data1, size1);
 +      if (zh2 != NULL)
 +              ret |= zbud_remotify_zbud(&xh2, data2, size2);
 +      return ret;
 +}
 +
 +void zbud_remotify_pages(int nr)
 +{
 +      struct zbud_page *zbpg;
 +      int i, ret;
 +
 +      /*
 +       * for now just try remotifying unbuddied pages, starting with
 +       * least space avail
 +       */
 +      for (i = 0; i < MAX_CHUNK; i++) {
 +retry_unbud_list_i:
 +              preempt_disable();  /* enable in zbud_remotify_zbpg */
 +              spin_lock_bh(&zbud_budlists_spinlock);
 +              if (list_empty(&zbud_unbuddied[i].list)) {
 +                      spin_unlock_bh(&zbud_budlists_spinlock);
 +                      preempt_enable();
 +                      continue; /* next i in for loop */
 +              }
 +              list_for_each_entry(zbpg, &zbud_unbuddied[i].list, bud_list) {
 +                      if (unlikely(!spin_trylock(&zbpg->lock)))
 +                              continue; /* next list_for_each_entry */
 +                      zbud_unbuddied[i].count--;
 +                      /* want budlists unlocked when doing zbpg remotify */
 +                      spin_unlock_bh(&zbud_budlists_spinlock);
 +                      ret = zbud_remotify_zbpg(zbpg);
 +                      /* preemption is re-enabled in zbud_remotify_zbpg */
 +                      if (ret == 0) {
 +                              if (--nr <= 0)
 +                                      goto out;
 +                              goto retry_unbud_list_i;
 +                      }
 +                      /* if fail to remotify any page, quit */
 +                      pr_err("TESTING zbud_remotify_pages failed on page,"
 +                              " trying to re-add\n");
 +                      spin_lock_bh(&zbud_budlists_spinlock);
 +                      spin_lock(&zbpg->lock);
 +                      list_add_tail(&zbpg->bud_list, &zbud_unbuddied[i].list);
 +                      zbud_unbuddied[i].count++;
 +                      spin_unlock(&zbpg->lock);
 +                      spin_unlock_bh(&zbud_budlists_spinlock);
 +                      pr_err("TESTING zbud_remotify_pages failed on page,"
 +                              " finished re-add\n");
 +                      goto out;
 +              }
 +              spin_unlock_bh(&zbud_budlists_spinlock);
 +              preempt_enable();
 +      }
 +
 +next_buddied_zbpg:
 +      preempt_disable();  /* enable in zbud_remotify_zbpg */
 +      spin_lock_bh(&zbud_budlists_spinlock);
 +      if (list_empty(&zbud_buddied_list))
 +              goto unlock_out;
 +      list_for_each_entry(zbpg, &zbud_buddied_list, bud_list) {
 +              if (unlikely(!spin_trylock(&zbpg->lock)))
 +                      continue; /* next list_for_each_entry */
 +              zcache_zbud_buddied_count--;
 +              /* want budlists unlocked when doing zbpg remotify */
 +              spin_unlock_bh(&zbud_budlists_spinlock);
 +              ret = zbud_remotify_zbpg(zbpg);
 +              /* preemption is re-enabled in zbud_remotify_zbpg */
 +              if (ret == 0) {
 +                      if (--nr <= 0)
 +                              goto out;
 +                      goto next_buddied_zbpg;
 +              }
 +              /* if fail to remotify any page, quit */
 +              pr_err("TESTING zbud_remotify_pages failed on BUDDIED page,"
 +                      " trying to re-add\n");
 +              spin_lock_bh(&zbud_budlists_spinlock);
 +              spin_lock(&zbpg->lock);
 +              list_add_tail(&zbpg->bud_list, &zbud_buddied_list);
 +              zcache_zbud_buddied_count++;
 +              spin_unlock(&zbpg->lock);
 +              spin_unlock_bh(&zbud_budlists_spinlock);
 +              pr_err("TESTING zbud_remotify_pages failed on BUDDIED page,"
 +                      " finished re-add\n");
 +              goto out;
 +      }
 +unlock_out:
 +      spin_unlock_bh(&zbud_budlists_spinlock);
 +      preempt_enable();
 +out:
 +      return;
 +}
 +
 +/* the "flush list" asynchronously collects pages to remotely flush */
 +#define FLUSH_ENTIRE_OBJECT ((uint32_t)-1)
 +static void ramster_flnode_free(struct flushlist_node *,
 +                              struct tmem_pool *);
 +
 +static void zcache_remote_flush_page(struct flushlist_node *flnode)
 +{
 +      struct tmem_xhandle *xh;
 +      int remotenode, ret;
 +
 +      preempt_disable();
 +      xh = &flnode->xh;
 +      remotenode = flnode->xh.client_id;
 +      ret = ramster_remote_flush(xh, remotenode);
 +      if (ret >= 0)
 +              ramster_remote_pages_flushed++;
 +      else
 +              ramster_remote_page_flushes_failed++;
 +      preempt_enable_no_resched();
 +      ramster_flnode_free(flnode, NULL);
 +}
 +
 +static void zcache_remote_flush_object(struct flushlist_node *flnode)
 +{
 +      struct tmem_xhandle *xh;
 +      int remotenode, ret;
 +
 +      preempt_disable();
 +      xh = &flnode->xh;
 +      remotenode = flnode->xh.client_id;
 +      ret = ramster_remote_flush_object(xh, remotenode);
 +      if (ret >= 0)
 +              ramster_remote_objects_flushed++;
 +      else
 +              ramster_remote_object_flushes_failed++;
 +      preempt_enable_no_resched();
 +      ramster_flnode_free(flnode, NULL);
 +}
 +
 +static void zcache_remote_eph_put(struct zbud_hdr *zbud)
 +{
 +      /* FIXME */
 +}
 +
 +static void zcache_remote_pers_put(struct zv_hdr *zv)
 +{
 +      struct tmem_xhandle xh;
 +      uint16_t size;
 +      bool ephemeral;
 +      int remotenode, ret = -1;
 +      char *data;
 +      struct tmem_pool *pool;
 +      unsigned long flags;
 +      unsigned char cksum;
 +      char *p;
 +      int i;
 +      unsigned char *tmpmem = __get_cpu_var(zcache_remoteputmem);
 +
 +      ASSERT_SENTINEL(zv, ZVH);
 +      BUG_ON(zv->client_id != LOCAL_CLIENT);
 +      local_bh_disable();
 +      xh.client_id = zv->client_id;
 +      xh.pool_id = zv->pool_id;
 +      xh.oid = zv->oid;
 +      xh.index = zv->index;
 +      size = xv_get_object_size(zv) - sizeof(*zv);
 +      BUG_ON(size == 0 || size > zv_max_page_size);
 +      data = (char *)zv + sizeof(*zv);
 +      for (p = data, cksum = 0, i = 0; i < size; i++)
 +              cksum += *p;
 +      memcpy(tmpmem, data, size);
 +      data = tmpmem;
 +      pool = zcache_get_pool_by_id(zv->client_id, zv->pool_id);
 +      ephemeral = is_ephemeral(pool);
 +      zcache_put_pool(pool);
 +      /* now OK to release lock set in caller */
 +      spin_unlock(&zcache_rem_op_list_lock);
 +      local_bh_enable();
 +      preempt_disable();
 +      ret = ramster_remote_put(&xh, data, size, ephemeral, &remotenode);
 +      preempt_enable_no_resched();
 +      if (ret != 0) {
 +              /*
 +               * This is some form of a memory leak... if the remote put
 +               * fails, there will never be another attempt to remotify
 +               * this page.  But since we've dropped the zv pointer,
 +               * the page may have been freed or the data replaced
 +               * so we can't just "put it back" in the remote op list.
 +               * Even if we could, not sure where to put it in the list
 +               * because there may be flushes that must be strictly
 +               * ordered vs the put.  So leave this as a FIXME for now.
 +               * But count them so we know if it becomes a problem.
 +               */
 +              ramster_pers_pages_remote_failed++;
 +              goto out;
 +      } else
 +              atomic_inc(&ramster_remote_pers_pages);
 +      ramster_pers_pages_remoted++;
 +      /*
 +       * data was successfully remoted so change the local version to
 +       * point to the remote node where it landed
 +       */
 +      local_bh_disable();
 +      pool = zcache_get_pool_by_id(LOCAL_CLIENT, xh.pool_id);
 +      local_irq_save(flags);
 +      (void)tmem_replace(pool, &xh.oid, xh.index,
 +                      pampd_make_remote(remotenode, size, cksum));
 +      local_irq_restore(flags);
 +      zcache_put_pool(pool);
 +      local_bh_enable();
 +out:
 +      return;
 +}
 +
 +static void zcache_do_remotify_ops(int nr)
 +{
 +      struct ramster_remotify_hdr *rem_op;
 +      union remotify_list_node *u;
 +
 +      while (1) {
 +              if (!nr)
 +                      goto out;
 +              spin_lock(&zcache_rem_op_list_lock);
 +              if (list_empty(&zcache_rem_op_list)) {
 +                      spin_unlock(&zcache_rem_op_list_lock);
 +                      goto out;
 +              }
 +              rem_op = list_first_entry(&zcache_rem_op_list,
 +                              struct ramster_remotify_hdr, list);
 +              list_del_init(&rem_op->list);
 +              if (rem_op->op != RAMSTER_REMOTIFY_PERS_PUT)
 +                      spin_unlock(&zcache_rem_op_list_lock);
 +              u = (union remotify_list_node *)rem_op;
 +              switch (rem_op->op) {
 +              case RAMSTER_REMOTIFY_EPH_PUT:
 +BUG();
 +                      zcache_remote_eph_put((struct zbud_hdr *)rem_op);
 +                      break;
 +              case RAMSTER_REMOTIFY_PERS_PUT:
 +                      zcache_remote_pers_put((struct zv_hdr *)rem_op);
 +                      break;
 +              case RAMSTER_REMOTIFY_FLUSH_PAGE:
 +                      zcache_remote_flush_page((struct flushlist_node *)u);
 +                      break;
 +              case RAMSTER_REMOTIFY_FLUSH_OBJ:
 +                      zcache_remote_flush_object((struct flushlist_node *)u);
 +                      break;
 +              default:
 +                      BUG();
 +              }
 +      }
 +out:
 +      return;
 +}
 +
 +/*
 + * Communicate interface revision with userspace
 + */
 +#include "cluster/ramster_nodemanager.h"
 +static unsigned long ramster_interface_revision  = R2NM_API_VERSION;
 +
 +/*
 + * For now, just push over a few pages every few seconds to
 + * ensure that it basically works
 + */
 +static struct workqueue_struct *ramster_remotify_workqueue;
 +static void ramster_remotify_process(struct work_struct *work);
 +static DECLARE_DELAYED_WORK(ramster_remotify_worker,
 +              ramster_remotify_process);
 +
 +static void ramster_remotify_queue_delayed_work(unsigned long delay)
 +{
 +      if (!queue_delayed_work(ramster_remotify_workqueue,
 +                              &ramster_remotify_worker, delay))
 +              pr_err("ramster_remotify: bad workqueue\n");
 +}
 +
 +
 +static int use_frontswap;
 +static int use_cleancache;
 +static int ramster_remote_target_nodenum = -1;
 +static void ramster_remotify_process(struct work_struct *work)
 +{
 +      static bool remotify_in_progress;
 +
 +      BUG_ON(irqs_disabled());
 +      if (remotify_in_progress)
 +              ramster_remotify_queue_delayed_work(HZ);
 +      else if (ramster_remote_target_nodenum != -1) {
 +              remotify_in_progress = true;
 +#ifdef CONFIG_CLEANCACHE
 +      if (use_cleancache && ramster_eph_remotify_enable)
 +              zbud_remotify_pages(5000); /* FIXME is this a good number? */
 +#endif
 +#ifdef CONFIG_FRONTSWAP
 +      if (use_frontswap && ramster_pers_remotify_enable)
 +              zcache_do_remotify_ops(500); /* FIXME is this a good number? */
 +#endif
 +              remotify_in_progress = false;
 +              ramster_remotify_queue_delayed_work(HZ);
 +      }
 +}
 +
 +static void ramster_remotify_init(void)
 +{
 +      unsigned long n = 60UL;
 +      ramster_remotify_workqueue =
 +              create_singlethread_workqueue("ramster_remotify");
 +      ramster_remotify_queue_delayed_work(n * HZ);
 +}
 +
 +
 +static void zbud_init(void)
 +{
 +      int i;
 +
 +      INIT_LIST_HEAD(&zbud_buddied_list);
 +      zcache_zbud_buddied_count = 0;
 +      for (i = 0; i < NCHUNKS; i++) {
 +              INIT_LIST_HEAD(&zbud_unbuddied[i].list);
 +              zbud_unbuddied[i].count = 0;
 +      }
 +}
 +
 +#ifdef CONFIG_SYSFS
 +/*
 + * These sysfs routines show a nice distribution of how many zbpg's are
 + * currently (and have ever been placed) in each unbuddied list.  It's fun
 + * to watch but can probably go away before final merge.
 + */
 +static int zbud_show_unbuddied_list_counts(char *buf)
 +{
 +      int i;
 +      char *p = buf;
 +
 +      for (i = 0; i < NCHUNKS; i++)
 +              p += sprintf(p, "%u ", zbud_unbuddied[i].count);
 +      return p - buf;
 +}
 +
 +static int zbud_show_cumul_chunk_counts(char *buf)
 +{
 +      unsigned long i, chunks = 0, total_chunks = 0, sum_total_chunks = 0;
 +      unsigned long total_chunks_lte_21 = 0, total_chunks_lte_32 = 0;
 +      unsigned long total_chunks_lte_42 = 0;
 +      char *p = buf;
 +
 +      for (i = 0; i < NCHUNKS; i++) {
 +              p += sprintf(p, "%lu ", zbud_cumul_chunk_counts[i]);
 +              chunks += zbud_cumul_chunk_counts[i];
 +              total_chunks += zbud_cumul_chunk_counts[i];
 +              sum_total_chunks += i * zbud_cumul_chunk_counts[i];
 +              if (i == 21)
 +                      total_chunks_lte_21 = total_chunks;
 +              if (i == 32)
 +                      total_chunks_lte_32 = total_chunks;
 +              if (i == 42)
 +                      total_chunks_lte_42 = total_chunks;
 +      }
 +      p += sprintf(p, "<=21:%lu <=32:%lu <=42:%lu, mean:%lu\n",
 +              total_chunks_lte_21, total_chunks_lte_32, total_chunks_lte_42,
 +              chunks == 0 ? 0 : sum_total_chunks / chunks);
 +      return p - buf;
 +}
 +#endif
 +
 +/**********
 + * This "zv" PAM implementation combines the TLSF-based xvMalloc
 + * with lzo1x compression to maximize the amount of data that can
 + * be packed into a physical page.
 + *
 + * Zv represents a PAM page with the index and object (plus a "size" value
 + * necessary for decompression) immediately preceding the compressed data.
 + */
 +
 +/* rudimentary policy limits */
 +/* total number of persistent pages may not exceed this percentage */
 +static unsigned int zv_page_count_policy_percent = 75;
 +/*
 + * byte count defining poor compression; pages with greater zsize will be
 + * rejected
 + */
 +static unsigned int zv_max_zsize = (PAGE_SIZE / 8) * 7;
 +/*
 + * byte count defining poor *mean* compression; pages with greater zsize
 + * will be rejected until sufficient better-compressed pages are accepted
 + * driving the mean below this threshold
 + */
 +static unsigned int zv_max_mean_zsize = (PAGE_SIZE / 8) * 5;
 +
 +static atomic_t zv_curr_dist_counts[NCHUNKS];
 +static atomic_t zv_cumul_dist_counts[NCHUNKS];
 +
 +
 +static struct zv_hdr *zv_create(struct zcache_client *cli, uint32_t pool_id,
 +                              struct tmem_oid *oid, uint32_t index,
 +                              void *cdata, unsigned clen)
 +{
 +      struct page *page;
 +      struct zv_hdr *zv = NULL;
 +      uint32_t offset;
 +      int alloc_size = clen + sizeof(struct zv_hdr);
 +      int chunks = (alloc_size + (CHUNK_SIZE - 1)) >> CHUNK_SHIFT;
 +      int ret;
 +
 +      BUG_ON(!irqs_disabled());
 +      BUG_ON(chunks >= NCHUNKS);
 +      ret = xv_malloc(cli->xvpool, clen + sizeof(struct zv_hdr),
 +                      &page, &offset, ZCACHE_GFP_MASK);
 +      if (unlikely(ret))
 +              goto out;
 +      atomic_inc(&zv_curr_dist_counts[chunks]);
 +      atomic_inc(&zv_cumul_dist_counts[chunks]);
-       zv = kmap_atomic(page, KM_USER0) + offset;
++      zv = kmap_atomic(page) + offset;
 +      zv->index = index;
 +      zv->oid = *oid;
 +      zv->pool_id = pool_id;
 +      SET_SENTINEL(zv, ZVH);
 +      INIT_LIST_HEAD(&zv->rem_op.list);
 +      zv->client_id = get_client_id_from_client(cli);
 +      zv->rem_op.op = RAMSTER_REMOTIFY_PERS_PUT;
 +      if (zv->client_id == LOCAL_CLIENT) {
 +              spin_lock(&zcache_rem_op_list_lock);
 +              list_add_tail(&zv->rem_op.list, &zcache_rem_op_list);
 +              spin_unlock(&zcache_rem_op_list_lock);
 +      }
 +      memcpy((char *)zv + sizeof(struct zv_hdr), cdata, clen);
-       kunmap_atomic(zv, KM_USER0);
++      kunmap_atomic(zv);
 +out:
 +      return zv;
 +}
 +
 +/* similar to zv_create, but just reserve space, no data yet */
 +static struct zv_hdr *zv_alloc(struct tmem_pool *pool,
 +                              struct tmem_oid *oid, uint32_t index,
 +                              unsigned clen)
 +{
 +      struct zcache_client *cli = pool->client;
 +      struct page *page;
 +      struct zv_hdr *zv = NULL;
 +      uint32_t offset;
 +      int ret;
 +
 +      BUG_ON(!irqs_disabled());
 +      BUG_ON(!is_local_client(pool->client));
 +      ret = xv_malloc(cli->xvpool, clen + sizeof(struct zv_hdr),
 +                      &page, &offset, ZCACHE_GFP_MASK);
 +      if (unlikely(ret))
 +              goto out;
-       zv = kmap_atomic(page, KM_USER0) + offset;
++      zv = kmap_atomic(page) + offset;
 +      SET_SENTINEL(zv, ZVH);
 +      INIT_LIST_HEAD(&zv->rem_op.list);
 +      zv->client_id = LOCAL_CLIENT;
 +      zv->rem_op.op = RAMSTER_INTRANSIT_PERS;
 +      zv->index = index;
 +      zv->oid = *oid;
 +      zv->pool_id = pool->pool_id;
-       kunmap_atomic(zv, KM_USER0);
++      kunmap_atomic(zv);
 +out:
 +      return zv;
 +}
 +
 +static void zv_free(struct xv_pool *xvpool, struct zv_hdr *zv)
 +{
 +      unsigned long flags;
 +      struct page *page;
 +      uint32_t offset;
 +      uint16_t size = xv_get_object_size(zv);
 +      int chunks = (size + (CHUNK_SIZE - 1)) >> CHUNK_SHIFT;
 +
 +      ASSERT_SENTINEL(zv, ZVH);
 +      BUG_ON(chunks >= NCHUNKS);
 +      atomic_dec(&zv_curr_dist_counts[chunks]);
 +      size -= sizeof(*zv);
 +      spin_lock(&zcache_rem_op_list_lock);
 +      size = xv_get_object_size(zv) - sizeof(*zv);
 +      BUG_ON(size == 0);
 +      INVERT_SENTINEL(zv, ZVH);
 +      if (!list_empty(&zv->rem_op.list))
 +              list_del_init(&zv->rem_op.list);
 +      spin_unlock(&zcache_rem_op_list_lock);
 +      page = virt_to_page(zv);
 +      offset = (unsigned long)zv & ~PAGE_MASK;
 +      local_irq_save(flags);
 +      xv_free(xvpool, page, offset);
 +      local_irq_restore(flags);
 +}
 +
 +static void zv_decompress(struct page *page, struct zv_hdr *zv)
 +{
 +      size_t clen = PAGE_SIZE;
 +      char *to_va;
 +      unsigned size;
 +      int ret;
 +
 +      ASSERT_SENTINEL(zv, ZVH);
 +      size = xv_get_object_size(zv) - sizeof(*zv);
 +      BUG_ON(size == 0);
-       to_va = kmap_atomic(page, KM_USER0);
++      to_va = kmap_atomic(page);
 +      ret = lzo1x_decompress_safe((char *)zv + sizeof(*zv),
 +                                      size, to_va, &clen);
-       kunmap_atomic(to_va, KM_USER0);
++      kunmap_atomic(to_va);
 +      BUG_ON(ret != LZO_E_OK);
 +      BUG_ON(clen != PAGE_SIZE);
 +}
 +
 +static void zv_copy_from_pampd(char *data, size_t *bufsize, struct zv_hdr *zv)
 +{
 +      unsigned size;
 +
 +      ASSERT_SENTINEL(zv, ZVH);
 +      size = xv_get_object_size(zv) - sizeof(*zv);
 +      BUG_ON(size == 0 || size > zv_max_page_size);
 +      BUG_ON(size > *bufsize);
 +      memcpy(data, (char *)zv + sizeof(*zv), size);
 +      *bufsize = size;
 +}
 +
 +static void zv_copy_to_pampd(struct zv_hdr *zv, char *data, size_t size)
 +{
 +      unsigned zv_size;
 +
 +      ASSERT_SENTINEL(zv, ZVH);
 +      zv_size = xv_get_object_size(zv) - sizeof(*zv);
 +      BUG_ON(zv_size != size);
 +      BUG_ON(zv_size == 0 || zv_size > zv_max_page_size);
 +      memcpy((char *)zv + sizeof(*zv), data, size);
 +}
 +
 +#ifdef CONFIG_SYSFS
 +/*
 + * show a distribution of compression stats for zv pages.
 + */
 +
 +static int zv_curr_dist_counts_show(char *buf)
 +{
 +      unsigned long i, n, chunks = 0, sum_total_chunks = 0;
 +      char *p = buf;
 +
 +      for (i = 0; i < NCHUNKS; i++) {
 +              n = atomic_read(&zv_curr_dist_counts[i]);
 +              p += sprintf(p, "%lu ", n);
 +              chunks += n;
 +              sum_total_chunks += i * n;
 +      }
 +      p += sprintf(p, "mean:%lu\n",
 +              chunks == 0 ? 0 : sum_total_chunks / chunks);
 +      return p - buf;
 +}
 +
 +static int zv_cumul_dist_counts_show(char *buf)
 +{
 +      unsigned long i, n, chunks = 0, sum_total_chunks = 0;
 +      char *p = buf;
 +
 +      for (i = 0; i < NCHUNKS; i++) {
 +              n = atomic_read(&zv_cumul_dist_counts[i]);
 +              p += sprintf(p, "%lu ", n);
 +              chunks += n;
 +              sum_total_chunks += i * n;
 +      }
 +      p += sprintf(p, "mean:%lu\n",
 +              chunks == 0 ? 0 : sum_total_chunks / chunks);
 +      return p - buf;
 +}
 +
 +/*
 + * setting zv_max_zsize via sysfs causes all persistent (e.g. swap)
 + * pages that don't compress to less than this value (including metadata
 + * overhead) to be rejected.  We don't allow the value to get too close
 + * to PAGE_SIZE.
 + */
 +static ssize_t zv_max_zsize_show(struct kobject *kobj,
 +                                  struct kobj_attribute *attr,
 +                                  char *buf)
 +{
 +      return sprintf(buf, "%u\n", zv_max_zsize);
 +}
 +
 +static ssize_t zv_max_zsize_store(struct kobject *kobj,
 +                                  struct kobj_attribute *attr,
 +                                  const char *buf, size_t count)
 +{
 +      unsigned long val;
 +      int err;
 +
 +      if (!capable(CAP_SYS_ADMIN))
 +              return -EPERM;
 +
 +      err = kstrtoul(buf, 10, &val);
 +      if (err || (val == 0) || (val > (PAGE_SIZE / 8) * 7))
 +              return -EINVAL;
 +      zv_max_zsize = val;
 +      return count;
 +}
 +
 +/*
 + * setting zv_max_mean_zsize via sysfs causes all persistent (e.g. swap)
 + * pages that don't compress to less than this value (including metadata
 + * overhead) to be rejected UNLESS the mean compression is also smaller
 + * than this value.  In other words, we are load-balancing-by-zsize the
 + * accepted pages.  Again, we don't allow the value to get too close
 + * to PAGE_SIZE.
 + */
 +static ssize_t zv_max_mean_zsize_show(struct kobject *kobj,
 +                                  struct kobj_attribute *attr,
 +                                  char *buf)
 +{
 +      return sprintf(buf, "%u\n", zv_max_mean_zsize);
 +}
 +
 +static ssize_t zv_max_mean_zsize_store(struct kobject *kobj,
 +                                  struct kobj_attribute *attr,
 +                                  const char *buf, size_t count)
 +{
 +      unsigned long val;
 +      int err;
 +
 +      if (!capable(CAP_SYS_ADMIN))
 +              return -EPERM;
 +
 +      err = kstrtoul(buf, 10, &val);
 +      if (err || (val == 0) || (val > (PAGE_SIZE / 8) * 7))
 +              return -EINVAL;
 +      zv_max_mean_zsize = val;
 +      return count;
 +}
 +
 +/*
 + * setting zv_page_count_policy_percent via sysfs sets an upper bound of
 + * persistent (e.g. swap) pages that will be retained according to:
 + *     (zv_page_count_policy_percent * totalram_pages) / 100)
 + * when that limit is reached, further puts will be rejected (until
 + * some pages have been flushed).  Note that, due to compression,
 + * this number may exceed 100; it defaults to 75 and we set an
 + * arbitary limit of 150.  A poor choice will almost certainly result
 + * in OOM's, so this value should only be changed prudently.
 + */
 +static ssize_t zv_page_count_policy_percent_show(struct kobject *kobj,
 +                                               struct kobj_attribute *attr,
 +                                               char *buf)
 +{
 +      return sprintf(buf, "%u\n", zv_page_count_policy_percent);
 +}
 +
 +static ssize_t zv_page_count_policy_percent_store(struct kobject *kobj,
 +                                                struct kobj_attribute *attr,
 +                                                const char *buf, size_t count)
 +{
 +      unsigned long val;
 +      int err;
 +
 +      if (!capable(CAP_SYS_ADMIN))
 +              return -EPERM;
 +
 +      err = kstrtoul(buf, 10, &val);
 +      if (err || (val == 0) || (val > 150))
 +              return -EINVAL;
 +      zv_page_count_policy_percent = val;
 +      return count;
 +}
 +
 +static struct kobj_attribute zcache_zv_max_zsize_attr = {
 +              .attr = { .name = "zv_max_zsize", .mode = 0644 },
 +              .show = zv_max_zsize_show,
 +              .store = zv_max_zsize_store,
 +};
 +
 +static struct kobj_attribute zcache_zv_max_mean_zsize_attr = {
 +              .attr = { .name = "zv_max_mean_zsize", .mode = 0644 },
 +              .show = zv_max_mean_zsize_show,
 +              .store = zv_max_mean_zsize_store,
 +};
 +
 +static struct kobj_attribute zcache_zv_page_count_policy_percent_attr = {
 +              .attr = { .name = "zv_page_count_policy_percent",
 +                        .mode = 0644 },
 +              .show = zv_page_count_policy_percent_show,
 +              .store = zv_page_count_policy_percent_store,
 +};
 +#endif
 +
 +/*
 + * zcache core code starts here
 + */
 +
 +/* useful stats not collected by cleancache or frontswap */
 +static unsigned long zcache_flush_total;
 +static unsigned long zcache_flush_found;
 +static unsigned long zcache_flobj_total;
 +static unsigned long zcache_flobj_found;
 +static unsigned long zcache_failed_eph_puts;
 +static unsigned long zcache_nonactive_puts;
 +static unsigned long zcache_failed_pers_puts;
 +
 +/*
 + * Tmem operations assume the poolid implies the invoking client.
 + * Zcache only has one client (the kernel itself): LOCAL_CLIENT.
 + * RAMster has each client numbered by cluster node, and a KVM version
 + * of zcache would have one client per guest and each client might
 + * have a poolid==N.
 + */
 +static struct tmem_pool *zcache_get_pool_by_id(uint16_t cli_id, uint16_t poolid)
 +{
 +      struct tmem_pool *pool = NULL;
 +      struct zcache_client *cli = NULL;
 +
 +      if (cli_id == LOCAL_CLIENT)
 +              cli = &zcache_host;
 +      else {
 +              if (cli_id >= MAX_CLIENTS)
 +                      goto out;
 +              cli = &zcache_clients[cli_id];
 +              if (cli == NULL)
 +                      goto out;
 +              atomic_inc(&cli->refcount);
 +      }
 +      if (poolid < MAX_POOLS_PER_CLIENT) {
 +              pool = cli->tmem_pools[poolid];
 +              if (pool != NULL)
 +                      atomic_inc(&pool->refcount);
 +      }
 +out:
 +      return pool;
 +}
 +
 +static void zcache_put_pool(struct tmem_pool *pool)
 +{
 +      struct zcache_client *cli = NULL;
 +
 +      if (pool == NULL)
 +              BUG();
 +      cli = pool->client;
 +      atomic_dec(&pool->refcount);
 +      atomic_dec(&cli->refcount);
 +}
 +
 +int zcache_new_client(uint16_t cli_id)
 +{
 +      struct zcache_client *cli = NULL;
 +      int ret = -1;
 +
 +      if (cli_id == LOCAL_CLIENT)
 +              cli = &zcache_host;
 +      else if ((unsigned int)cli_id < MAX_CLIENTS)
 +              cli = &zcache_clients[cli_id];
 +      if (cli == NULL)
 +              goto out;
 +      if (cli->allocated)
 +              goto out;
 +      cli->allocated = 1;
 +#ifdef CONFIG_FRONTSWAP
 +      cli->xvpool = xv_create_pool();
 +      if (cli->xvpool == NULL)
 +              goto out;
 +#endif
 +      ret = 0;
 +out:
 +      return ret;
 +}
 +
 +/* counters for debugging */
 +static unsigned long zcache_failed_get_free_pages;
 +static unsigned long zcache_failed_alloc;
 +static unsigned long zcache_put_to_flush;
 +
 +/*
 + * for now, used named slabs so can easily track usage; later can
 + * either just use kmalloc, or perhaps add a slab-like allocator
 + * to more carefully manage total memory utilization
 + */
 +static struct kmem_cache *zcache_objnode_cache;
 +static struct kmem_cache *zcache_obj_cache;
 +static struct kmem_cache *ramster_flnode_cache;
 +static atomic_t zcache_curr_obj_count = ATOMIC_INIT(0);
 +static unsigned long zcache_curr_obj_count_max;
 +static atomic_t zcache_curr_objnode_count = ATOMIC_INIT(0);
 +static unsigned long zcache_curr_objnode_count_max;
 +
 +/*
 + * to avoid memory allocation recursion (e.g. due to direct reclaim), we
 + * preload all necessary data structures so the hostops callbacks never
 + * actually do a malloc
 + */
 +struct zcache_preload {
 +      void *page;
 +      struct tmem_obj *obj;
 +      int nr;
 +      struct tmem_objnode *objnodes[OBJNODE_TREE_MAX_PATH];
 +      struct flushlist_node *flnode;
 +};
 +static DEFINE_PER_CPU(struct zcache_preload, zcache_preloads) = { 0, };
 +
 +static int zcache_do_preload(struct tmem_pool *pool)
 +{
 +      struct zcache_preload *kp;
 +      struct tmem_objnode *objnode;
 +      struct tmem_obj *obj;
 +      struct flushlist_node *flnode;
 +      void *page;
 +      int ret = -ENOMEM;
 +
 +      if (unlikely(zcache_objnode_cache == NULL))
 +              goto out;
 +      if (unlikely(zcache_obj_cache == NULL))
 +              goto out;
 +      preempt_disable();
 +      kp = &__get_cpu_var(zcache_preloads);
 +      while (kp->nr < ARRAY_SIZE(kp->objnodes)) {
 +              preempt_enable_no_resched();
 +              objnode = kmem_cache_alloc(zcache_objnode_cache,
 +                              ZCACHE_GFP_MASK);
 +              if (unlikely(objnode == NULL)) {
 +                      zcache_failed_alloc++;
 +                      goto out;
 +              }
 +              preempt_disable();
 +              kp = &__get_cpu_var(zcache_preloads);
 +              if (kp->nr < ARRAY_SIZE(kp->objnodes))
 +                      kp->objnodes[kp->nr++] = objnode;
 +              else
 +                      kmem_cache_free(zcache_objnode_cache, objnode);
 +      }
 +      preempt_enable_no_resched();
 +      obj = kmem_cache_alloc(zcache_obj_cache, ZCACHE_GFP_MASK);
 +      if (unlikely(obj == NULL)) {
 +              zcache_failed_alloc++;
 +              goto out;
 +      }
 +      flnode = kmem_cache_alloc(ramster_flnode_cache, ZCACHE_GFP_MASK);
 +      if (unlikely(flnode == NULL)) {
 +              zcache_failed_alloc++;
 +              goto out;
 +      }
 +      if (is_ephemeral(pool)) {
 +              page = (void *)__get_free_page(ZCACHE_GFP_MASK);
 +              if (unlikely(page == NULL)) {
 +                      zcache_failed_get_free_pages++;
 +                      kmem_cache_free(zcache_obj_cache, obj);
 +                      kmem_cache_free(ramster_flnode_cache, flnode);
 +                      goto out;
 +              }
 +      }
 +      preempt_disable();
 +      kp = &__get_cpu_var(zcache_preloads);
 +      if (kp->obj == NULL)
 +              kp->obj = obj;
 +      else
 +              kmem_cache_free(zcache_obj_cache, obj);
 +      if (kp->flnode == NULL)
 +              kp->flnode = flnode;
 +      else
 +              kmem_cache_free(ramster_flnode_cache, flnode);
 +      if (is_ephemeral(pool)) {
 +              if (kp->page == NULL)
 +                      kp->page = page;
 +              else
 +                      free_page((unsigned long)page);
 +      }
 +      ret = 0;
 +out:
 +      return ret;
 +}
 +
 +static int ramster_do_preload_flnode_only(struct tmem_pool *pool)
 +{
 +      struct zcache_preload *kp;
 +      struct flushlist_node *flnode;
 +      int ret = -ENOMEM;
 +
 +      BUG_ON(!irqs_disabled());
 +      if (unlikely(ramster_flnode_cache == NULL))
 +              BUG();
 +      kp = &__get_cpu_var(zcache_preloads);
 +      flnode = kmem_cache_alloc(ramster_flnode_cache, GFP_ATOMIC);
 +      if (unlikely(flnode == NULL) && kp->flnode == NULL)
 +              BUG();  /* FIXME handle more gracefully, but how??? */
 +      else if (kp->flnode == NULL)
 +              kp->flnode = flnode;
 +      else
 +              kmem_cache_free(ramster_flnode_cache, flnode);
 +      return ret;
 +}
 +
 +static void *zcache_get_free_page(void)
 +{
 +      struct zcache_preload *kp;
 +      void *page;
 +
 +      kp = &__get_cpu_var(zcache_preloads);
 +      page = kp->page;
 +      BUG_ON(page == NULL);
 +      kp->page = NULL;
 +      return page;
 +}
 +
 +static void zcache_free_page(void *p)
 +{
 +      free_page((unsigned long)p);
 +}
 +
 +/*
 + * zcache implementation for tmem host ops
 + */
 +
 +static struct tmem_objnode *zcache_objnode_alloc(struct tmem_pool *pool)
 +{
 +      struct tmem_objnode *objnode = NULL;
 +      unsigned long count;
 +      struct zcache_preload *kp;
 +
 +      kp = &__get_cpu_var(zcache_preloads);
 +      if (kp->nr <= 0)
 +              goto out;
 +      objnode = kp->objnodes[kp->nr - 1];
 +      BUG_ON(objnode == NULL);
 +      kp->objnodes[kp->nr - 1] = NULL;
 +      kp->nr--;
 +      count = atomic_inc_return(&zcache_curr_objnode_count);
 +      if (count > zcache_curr_objnode_count_max)
 +              zcache_curr_objnode_count_max = count;
 +out:
 +      return objnode;
 +}
 +
 +static void zcache_objnode_free(struct tmem_objnode *objnode,
 +                                      struct tmem_pool *pool)
 +{
 +      atomic_dec(&zcache_curr_objnode_count);
 +      BUG_ON(atomic_read(&zcache_curr_objnode_count) < 0);
 +      kmem_cache_free(zcache_objnode_cache, objnode);
 +}
 +
 +static struct tmem_obj *zcache_obj_alloc(struct tmem_pool *pool)
 +{
 +      struct tmem_obj *obj = NULL;
 +      unsigned long count;
 +      struct zcache_preload *kp;
 +
 +      kp = &__get_cpu_var(zcache_preloads);
 +      obj = kp->obj;
 +      BUG_ON(obj == NULL);
 +      kp->obj = NULL;
 +      count = atomic_inc_return(&zcache_curr_obj_count);
 +      if (count > zcache_curr_obj_count_max)
 +              zcache_curr_obj_count_max = count;
 +      return obj;
 +}
 +
 +static void zcache_obj_free(struct tmem_obj *obj, struct tmem_pool *pool)
 +{
 +      atomic_dec(&zcache_curr_obj_count);
 +      BUG_ON(atomic_read(&zcache_curr_obj_count) < 0);
 +      kmem_cache_free(zcache_obj_cache, obj);
 +}
 +
 +static struct flushlist_node *ramster_flnode_alloc(struct tmem_pool *pool)
 +{
 +      struct flushlist_node *flnode = NULL;
 +      struct zcache_preload *kp;
 +      int count;
 +
 +      kp = &__get_cpu_var(zcache_preloads);
 +      flnode = kp->flnode;
 +      BUG_ON(flnode == NULL);
 +      kp->flnode = NULL;
 +      count = atomic_inc_return(&ramster_curr_flnode_count);
 +      if (count > ramster_curr_flnode_count_max)
 +              ramster_curr_flnode_count_max = count;
 +      return flnode;
 +}
 +
 +static void ramster_flnode_free(struct flushlist_node *flnode,
 +                              struct tmem_pool *pool)
 +{
 +      atomic_dec(&ramster_curr_flnode_count);
 +      BUG_ON(atomic_read(&ramster_curr_flnode_count) < 0);
 +      kmem_cache_free(ramster_flnode_cache, flnode);
 +}
 +
 +static struct tmem_hostops zcache_hostops = {
 +      .obj_alloc = zcache_obj_alloc,
 +      .obj_free = zcache_obj_free,
 +      .objnode_alloc = zcache_objnode_alloc,
 +      .objnode_free = zcache_objnode_free,
 +};
 +
 +/*
 + * zcache implementations for PAM page descriptor ops
 + */
 +
 +
 +static inline void dec_and_check(atomic_t *pvar)
 +{
 +      atomic_dec(pvar);
 +      /* later when all accounting is fixed, make this a BUG */
 +      WARN_ON_ONCE(atomic_read(pvar) < 0);
 +}
 +
 +static atomic_t zcache_curr_eph_pampd_count = ATOMIC_INIT(0);
 +static unsigned long zcache_curr_eph_pampd_count_max;
 +static atomic_t zcache_curr_pers_pampd_count = ATOMIC_INIT(0);
 +static unsigned long zcache_curr_pers_pampd_count_max;
 +
 +/* forward reference */
 +static int zcache_compress(struct page *from, void **out_va, size_t *out_len);
 +
 +static int zcache_pampd_eph_create(char *data, size_t size, bool raw,
 +                              struct tmem_pool *pool, struct tmem_oid *oid,
 +                              uint32_t index, void **pampd)
 +{
 +      int ret = -1;
 +      void *cdata = data;
 +      size_t clen = size;
 +      struct zcache_client *cli = pool->client;
 +      uint16_t client_id = get_client_id_from_client(cli);
 +      struct page *page = NULL;
 +      unsigned long count;
 +
 +      if (!raw) {
 +              page = virt_to_page(data);
 +              ret = zcache_compress(page, &cdata, &clen);
 +              if (ret == 0)
 +                      goto out;
 +              if (clen == 0 || clen > zbud_max_buddy_size()) {
 +                      zcache_compress_poor++;
 +                      goto out;
 +              }
 +      }
 +      *pampd = (void *)zbud_create(client_id, pool->pool_id, oid,
 +                                      index, page, cdata, clen);
 +      if (*pampd == NULL) {
 +              ret = -ENOMEM;
 +              goto out;
 +      }
 +      ret = 0;
 +      count = atomic_inc_return(&zcache_curr_eph_pampd_count);
 +      if (count > zcache_curr_eph_pampd_count_max)
 +              zcache_curr_eph_pampd_count_max = count;
 +      if (client_id != LOCAL_CLIENT) {
 +              count = atomic_inc_return(&ramster_foreign_eph_pampd_count);
 +              if (count > ramster_foreign_eph_pampd_count_max)
 +                      ramster_foreign_eph_pampd_count_max = count;
 +      }
 +out:
 +      return ret;
 +}
 +
 +static int zcache_pampd_pers_create(char *data, size_t size, bool raw,
 +                              struct tmem_pool *pool, struct tmem_oid *oid,
 +                              uint32_t index, void **pampd)
 +{
 +      int ret = -1;
 +      void *cdata = data;
 +      size_t clen = size;
 +      struct zcache_client *cli = pool->client;
 +      struct page *page;
 +      unsigned long count;
 +      unsigned long zv_mean_zsize;
 +      struct zv_hdr *zv;
 +      long curr_pers_pampd_count;
 +      u64 total_zsize;
 +#ifdef RAMSTER_TESTING
 +      static bool pampd_neg_warned;
 +#endif
 +
 +      curr_pers_pampd_count = atomic_read(&zcache_curr_pers_pampd_count) -
 +                      atomic_read(&ramster_remote_pers_pages);
 +#ifdef RAMSTER_TESTING
 +      /* should always be positive, but warn if accounting is off */
 +      if (!pampd_neg_warned) {
 +              pr_warn("ramster: bad accounting for curr_pers_pampd_count\n");
 +              pampd_neg_warned = true;
 +      }
 +#endif
 +      if (curr_pers_pampd_count >
 +                  (zv_page_count_policy_percent * totalram_pages) / 100) {
 +              zcache_policy_percent_exceeded++;
 +              goto out;
 +      }
 +      if (raw)
 +              goto ok_to_create;
 +      page = virt_to_page(data);
 +      if (zcache_compress(page, &cdata, &clen) == 0)
 +              goto out;
 +      /* reject if compression is too poor */
 +      if (clen > zv_max_zsize) {
 +              zcache_compress_poor++;
 +              goto out;
 +      }
 +      /* reject if mean compression is too poor */
 +      if ((clen > zv_max_mean_zsize) && (curr_pers_pampd_count > 0)) {
 +              total_zsize = xv_get_total_size_bytes(cli->xvpool);
 +              zv_mean_zsize = div_u64(total_zsize, curr_pers_pampd_count);
 +              if (zv_mean_zsize > zv_max_mean_zsize) {
 +                      zcache_mean_compress_poor++;
 +                      goto out;
 +              }
 +      }
 +ok_to_create:
 +      *pampd = (void *)zv_create(cli, pool->pool_id, oid, index, cdata, clen);
 +      if (*pampd == NULL) {
 +              ret = -ENOMEM;
 +              goto out;
 +      }
 +      ret = 0;
 +      count = atomic_inc_return(&zcache_curr_pers_pampd_count);
 +      if (count > zcache_curr_pers_pampd_count_max)
 +              zcache_curr_pers_pampd_count_max = count;
 +      if (is_local_client(cli))
 +              goto out;
 +      zv = *(struct zv_hdr **)pampd;
 +      count = atomic_inc_return(&ramster_foreign_pers_pampd_count);
 +      if (count > ramster_foreign_pers_pampd_count_max)
 +              ramster_foreign_pers_pampd_count_max = count;
 +out:
 +      return ret;
 +}
 +
 +static void *zcache_pampd_create(char *data, size_t size, bool raw, int eph,
 +                              struct tmem_pool *pool, struct tmem_oid *oid,
 +                              uint32_t index)
 +{
 +      void *pampd = NULL;
 +      int ret;
 +      bool ephemeral;
 +
 +      BUG_ON(preemptible());
 +      ephemeral = (eph == 1) || ((eph == 0) && is_ephemeral(pool));
 +      if (ephemeral)
 +              ret = zcache_pampd_eph_create(data, size, raw, pool,
 +                                              oid, index, &pampd);
 +      else
 +              ret = zcache_pampd_pers_create(data, size, raw, pool,
 +                                              oid, index, &pampd);
 +      /* FIXME add some counters here for failed creates? */
 +      return pampd;
 +}
 +
 +/*
 + * fill the pageframe corresponding to the struct page with the data
 + * from the passed pampd
 + */
 +static int zcache_pampd_get_data(char *data, size_t *bufsize, bool raw,
 +                                      void *pampd, struct tmem_pool *pool,
 +                                      struct tmem_oid *oid, uint32_t index)
 +{
 +      int ret = 0;
 +
 +      BUG_ON(preemptible());
 +      BUG_ON(is_ephemeral(pool)); /* Fix later for shared pools? */
 +      BUG_ON(pampd_is_remote(pampd));
 +      if (raw)
 +              zv_copy_from_pampd(data, bufsize, pampd);
 +      else
 +              zv_decompress(virt_to_page(data), pampd);
 +      return ret;
 +}
 +
 +static int zcache_pampd_get_data_and_free(char *data, size_t *bufsize, bool raw,
 +                                      void *pampd, struct tmem_pool *pool,
 +                                      struct tmem_oid *oid, uint32_t index)
 +{
 +      int ret = 0;
 +      unsigned long flags;
 +      struct zcache_client *cli = pool->client;
 +
 +      BUG_ON(preemptible());
 +      BUG_ON(pampd_is_remote(pampd));
 +      if (is_ephemeral(pool)) {
 +              local_irq_save(flags);
 +              if (raw)
 +                      zbud_copy_from_pampd(data, bufsize, pampd);
 +              else
 +                      ret = zbud_decompress(virt_to_page(data), pampd);
 +              zbud_free_and_delist((struct zbud_hdr *)pampd);
 +              local_irq_restore(flags);
 +              if (!is_local_client(cli))
 +                      dec_and_check(&ramster_foreign_eph_pampd_count);
 +              dec_and_check(&zcache_curr_eph_pampd_count);
 +      } else {
 +              if (is_local_client(cli))
 +                      BUG();
 +              if (raw)
 +                      zv_copy_from_pampd(data, bufsize, pampd);
 +              else
 +                      zv_decompress(virt_to_page(data), pampd);
 +              zv_free(cli->xvpool, pampd);
 +              if (!is_local_client(cli))
 +                      dec_and_check(&ramster_foreign_pers_pampd_count);
 +              dec_and_check(&zcache_curr_pers_pampd_count);
 +              ret = 0;
 +      }
 +      return ret;
 +}
 +
 +static bool zcache_pampd_is_remote(void *pampd)
 +{
 +      return pampd_is_remote(pampd);
 +}
 +
 +/*
 + * free the pampd and remove it from any zcache lists
 + * pampd must no longer be pointed to from any tmem data structures!
 + */
 +static void zcache_pampd_free(void *pampd, struct tmem_pool *pool,
 +                            struct tmem_oid *oid, uint32_t index, bool acct)
 +{
 +      struct zcache_client *cli = pool->client;
 +      bool eph = is_ephemeral(pool);
 +      struct zv_hdr *zv;
 +
 +      BUG_ON(preemptible());
 +      if (pampd_is_remote(pampd)) {
 +              WARN_ON(acct == false);
 +              if (oid == NULL) {
 +                      /*
 +                       * a NULL oid means to ignore this pampd free
 +                       * as the remote freeing will be handled elsewhere
 +                       */
 +              } else if (eph) {
 +                      /* FIXME remote flush optional but probably good idea */
 +                      /* FIXME get these working properly again */
 +                      dec_and_check(&zcache_curr_eph_pampd_count);
 +              } else if (pampd_is_intransit(pampd)) {
 +                      /* did a pers remote get_and_free, so just free local */
 +                      pampd = pampd_mask_intransit_and_remote(pampd);
 +                      goto local_pers;
 +              } else {
 +                      struct flushlist_node *flnode =
 +                              ramster_flnode_alloc(pool);
 +
 +                      flnode->xh.client_id = pampd_remote_node(pampd);
 +                      flnode->xh.pool_id = pool->pool_id;
 +                      flnode->xh.oid = *oid;
 +                      flnode->xh.index = index;
 +                      flnode->rem_op.op = RAMSTER_REMOTIFY_FLUSH_PAGE;
 +                      spin_lock(&zcache_rem_op_list_lock);
 +                      list_add(&flnode->rem_op.list, &zcache_rem_op_list);
 +                      spin_unlock(&zcache_rem_op_list_lock);
 +                      dec_and_check(&zcache_curr_pers_pampd_count);
 +                      dec_and_check(&ramster_remote_pers_pages);
 +              }
 +      } else if (eph) {
 +              zbud_free_and_delist((struct zbud_hdr *)pampd);
 +              if (!is_local_client(pool->client))
 +                      dec_and_check(&ramster_foreign_eph_pampd_count);
 +              if (acct)
 +                      /* FIXME get these working properly again */
 +                      dec_and_check(&zcache_curr_eph_pampd_count);
 +      } else {
 +local_pers:
 +              zv = (struct zv_hdr *)pampd;
 +              if (!is_local_client(pool->client))
 +                      dec_and_check(&ramster_foreign_pers_pampd_count);
 +              zv_free(cli->xvpool, zv);
 +              if (acct)
 +                      /* FIXME get these working properly again */
 +                      dec_and_check(&zcache_curr_pers_pampd_count);
 +      }
 +}
 +
 +static void zcache_pampd_free_obj(struct tmem_pool *pool,
 +                                      struct tmem_obj *obj)
 +{
 +      struct flushlist_node *flnode;
 +
 +      BUG_ON(preemptible());
 +      if (obj->extra == NULL)
 +              return;
 +      BUG_ON(!pampd_is_remote(obj->extra));
 +      flnode = ramster_flnode_alloc(pool);
 +      flnode->xh.client_id = pampd_remote_node(obj->extra);
 +      flnode->xh.pool_id = pool->pool_id;
 +      flnode->xh.oid = obj->oid;
 +      flnode->xh.index = FLUSH_ENTIRE_OBJECT;
 +      flnode->rem_op.op = RAMSTER_REMOTIFY_FLUSH_OBJ;
 +      spin_lock(&zcache_rem_op_list_lock);
 +      list_add(&flnode->rem_op.list, &zcache_rem_op_list);
 +      spin_unlock(&zcache_rem_op_list_lock);
 +}
 +
 +void zcache_pampd_new_obj(struct tmem_obj *obj)
 +{
 +      obj->extra = NULL;
 +}
 +
 +int zcache_pampd_replace_in_obj(void *new_pampd, struct tmem_obj *obj)
 +{
 +      int ret = -1;
 +
 +      if (new_pampd != NULL) {
 +              if (obj->extra == NULL)
 +                      obj->extra = new_pampd;
 +              /* enforce that all remote pages in an object reside
 +               * in the same node! */
 +              else if (pampd_remote_node(new_pampd) !=
 +                              pampd_remote_node((void *)(obj->extra)))
 +                      BUG();
 +              ret = 0;
 +      }
 +      return ret;
 +}
 +
 +/*
 + * Called by the message handler after a (still compressed) page has been
 + * fetched from the remote machine in response to an "is_remote" tmem_get
 + * or persistent tmem_localify.  For a tmem_get, "extra" is the address of
 + * the page that is to be filled to succesfully resolve the tmem_get; for
 + * a (persistent) tmem_localify, "extra" is NULL (as the data is placed only
 + * in the local zcache).  "data" points to "size" bytes of (compressed) data
 + * passed in the message.  In the case of a persistent remote get, if
 + * pre-allocation was successful (see zcache_repatriate_preload), the page
 + * is placed into both local zcache and at "extra".
 + */
 +int zcache_localify(int pool_id, struct tmem_oid *oidp,
 +                      uint32_t index, char *data, size_t size,
 +                      void *extra)
 +{
 +      int ret = -ENOENT;
 +      unsigned long flags;
 +      struct tmem_pool *pool;
 +      bool ephemeral, delete = false;
 +      size_t clen = PAGE_SIZE;
 +      void *pampd, *saved_hb;
 +      struct tmem_obj *obj;
 +
 +      pool = zcache_get_pool_by_id(LOCAL_CLIENT, pool_id);
 +      if (unlikely(pool == NULL))
 +              /* pool doesn't exist anymore */
 +              goto out;
 +      ephemeral = is_ephemeral(pool);
 +      local_irq_save(flags);  /* FIXME: maybe only disable softirqs? */
 +      pampd = tmem_localify_get_pampd(pool, oidp, index, &obj, &saved_hb);
 +      if (pampd == NULL) {
 +              /* hmmm... must have been a flush while waiting */
 +#ifdef RAMSTER_TESTING
 +              pr_err("UNTESTED pampd==NULL in zcache_localify\n");
 +#endif
 +              if (ephemeral)
 +                      ramster_remote_eph_pages_unsucc_get++;
 +              else
 +                      ramster_remote_pers_pages_unsucc_get++;
 +              obj = NULL;
 +              goto finish;
 +      } else if (unlikely(!pampd_is_remote(pampd))) {
 +              /* hmmm... must have been a dup put while waiting */
 +#ifdef RAMSTER_TESTING
 +              pr_err("UNTESTED dup while waiting in zcache_localify\n");
 +#endif
 +              if (ephemeral)
 +                      ramster_remote_eph_pages_unsucc_get++;
 +              else
 +                      ramster_remote_pers_pages_unsucc_get++;
 +              obj = NULL;
 +              pampd = NULL;
 +              ret = -EEXIST;
 +              goto finish;
 +      } else if (size == 0) {
 +              /* no remote data, delete the local is_remote pampd */
 +              pampd = NULL;
 +              if (ephemeral)
 +                      ramster_remote_eph_pages_unsucc_get++;
 +              else
 +                      BUG();
 +              delete = true;
 +              goto finish;
 +      }
 +      if (!ephemeral && pampd_is_intransit(pampd)) {
 +              /* localify to zcache */
 +              pampd = pampd_mask_intransit_and_remote(pampd);
 +              zv_copy_to_pampd(pampd, data, size);
 +      } else {
 +              pampd = NULL;
 +              obj = NULL;
 +      }
 +      if (extra != NULL) {
 +              /* decompress direct-to-memory to complete remotify */
 +              ret = lzo1x_decompress_safe((char *)data, size,
 +                                              (char *)extra, &clen);
 +              BUG_ON(ret != LZO_E_OK);
 +              BUG_ON(clen != PAGE_SIZE);
 +      }
 +      if (ephemeral)
 +              ramster_remote_eph_pages_succ_get++;
 +      else
 +              ramster_remote_pers_pages_succ_get++;
 +      ret = 0;
 +finish:
 +      tmem_localify_finish(obj, index, pampd, saved_hb, delete);
 +      zcache_put_pool(pool);
 +      local_irq_restore(flags);
 +out:
 +      return ret;
 +}
 +
 +/*
 + * Called on a remote persistent tmem_get to attempt to preallocate
 + * local storage for the data contained in the remote persistent page.
 + * If succesfully preallocated, returns the pampd, marked as remote and
 + * in_transit.  Else returns NULL.  Note that the appropriate tmem data
 + * structure must be locked.
 + */
 +static void *zcache_pampd_repatriate_preload(void *pampd,
 +                                              struct tmem_pool *pool,
 +                                              struct tmem_oid *oid,
 +                                              uint32_t index,
 +                                              bool *intransit)
 +{
 +      int clen = pampd_remote_size(pampd);
 +      void *ret_pampd = NULL;
 +      unsigned long flags;
 +
 +      if (!pampd_is_remote(pampd))
 +              BUG();
 +      if (is_ephemeral(pool))
 +              BUG();
 +      if (pampd_is_intransit(pampd)) {
 +              /*
 +               * to avoid multiple allocations (and maybe a memory leak)
 +               * don't preallocate if already in the process of being
 +               * repatriated
 +               */
 +              *intransit = true;
 +              goto out;
 +      }
 +      *intransit = false;
 +      local_irq_save(flags);
 +      ret_pampd = (void *)zv_alloc(pool, oid, index, clen);
 +      if (ret_pampd != NULL) {
 +              /*
 +               *  a pampd is marked intransit if it is remote and space has
 +               *  been allocated for it locally (note, only happens for
 +               *  persistent pages, in which case the remote copy is freed)
 +               */
 +              ret_pampd = pampd_mark_intransit(ret_pampd);
 +              dec_and_check(&ramster_remote_pers_pages);
 +      } else
 +              ramster_pers_pages_remote_nomem++;
 +      local_irq_restore(flags);
 +out:
 +      return ret_pampd;
 +}
 +
 +/*
 + * Called on a remote tmem_get to invoke a message to fetch the page.
 + * Might sleep so no tmem locks can be held.  "extra" is passed
 + * all the way through the round-trip messaging to zcache_localify.
 + */
 +static int zcache_pampd_repatriate(void *fake_pampd, void *real_pampd,
 +                                 struct tmem_pool *pool,
 +                                 struct tmem_oid *oid, uint32_t index,
 +                                 bool free, void *extra)
 +{
 +      struct tmem_xhandle xh;
 +      int ret;
 +
 +      if (pampd_is_intransit(real_pampd))
 +              /* have local space pre-reserved, so free remote copy */
 +              free = true;
 +      xh = tmem_xhandle_fill(LOCAL_CLIENT, pool, oid, index);
 +      /* unreliable request/response for now */
 +      ret = ramster_remote_async_get(&xh, free,
 +                                      pampd_remote_node(fake_pampd),
 +                                      pampd_remote_size(fake_pampd),
 +                                      pampd_remote_cksum(fake_pampd),
 +                                      extra);
 +#ifdef RAMSTER_TESTING
 +      if (ret != 0 && ret != -ENOENT)
 +              pr_err("TESTING zcache_pampd_repatriate returns, ret=%d\n",
 +                      ret);
 +#endif
 +      return ret;
 +}
 +
 +static struct tmem_pamops zcache_pamops = {
 +      .create = zcache_pampd_create,
 +      .get_data = zcache_pampd_get_data,
 +      .free = zcache_pampd_free,
 +      .get_data_and_free = zcache_pampd_get_data_and_free,
 +      .free_obj = zcache_pampd_free_obj,
 +      .is_remote = zcache_pampd_is_remote,
 +      .repatriate_preload = zcache_pampd_repatriate_preload,
 +      .repatriate = zcache_pampd_repatriate,
 +      .new_obj = zcache_pampd_new_obj,
 +      .replace_in_obj = zcache_pampd_replace_in_obj,
 +};
 +
 +/*
 + * zcache compression/decompression and related per-cpu stuff
 + */
 +
 +#define LZO_WORKMEM_BYTES LZO1X_1_MEM_COMPRESS
 +#define LZO_DSTMEM_PAGE_ORDER 1
 +static DEFINE_PER_CPU(unsigned char *, zcache_workmem);
 +static DEFINE_PER_CPU(unsigned char *, zcache_dstmem);
 +
 +static int zcache_compress(struct page *from, void **out_va, size_t *out_len)
 +{
 +      int ret = 0;
 +      unsigned char *dmem = __get_cpu_var(zcache_dstmem);
 +      unsigned char *wmem = __get_cpu_var(zcache_workmem);
 +      char *from_va;
 +
 +      BUG_ON(!irqs_disabled());
 +      if (unlikely(dmem == NULL || wmem == NULL))
 +              goto out;  /* no buffer, so can't compress */
-       from_va = kmap_atomic(from, KM_USER0);
++      from_va = kmap_atomic(from);
 +      mb();
 +      ret = lzo1x_1_compress(from_va, PAGE_SIZE, dmem, out_len, wmem);
 +      BUG_ON(ret != LZO_E_OK);
 +      *out_va = dmem;
-       kunmap_atomic(from_va, KM_USER0);
++      kunmap_atomic(from_va);
 +      ret = 1;
 +out:
 +      return ret;
 +}
 +
 +
 +static int zcache_cpu_notifier(struct notifier_block *nb,
 +                              unsigned long action, void *pcpu)
 +{
 +      int cpu = (long)pcpu;
 +      struct zcache_preload *kp;
 +
 +      switch (action) {
 +      case CPU_UP_PREPARE:
 +              per_cpu(zcache_dstmem, cpu) = (void *)__get_free_pages(
 +                      GFP_KERNEL | __GFP_REPEAT,
 +                      LZO_DSTMEM_PAGE_ORDER),
 +              per_cpu(zcache_workmem, cpu) =
 +                      kzalloc(LZO1X_MEM_COMPRESS,
 +                              GFP_KERNEL | __GFP_REPEAT);
 +              per_cpu(zcache_remoteputmem, cpu) =
 +                      kzalloc(PAGE_SIZE, GFP_KERNEL | __GFP_REPEAT);
 +              break;
 +      case CPU_DEAD:
 +      case CPU_UP_CANCELED:
 +              kfree(per_cpu(zcache_remoteputmem, cpu));
 +              per_cpu(zcache_remoteputmem, cpu) = NULL;
 +              free_pages((unsigned long)per_cpu(zcache_dstmem, cpu),
 +                              LZO_DSTMEM_PAGE_ORDER);
 +              per_cpu(zcache_dstmem, cpu) = NULL;
 +              kfree(per_cpu(zcache_workmem, cpu));
 +              per_cpu(zcache_workmem, cpu) = NULL;
 +              kp = &per_cpu(zcache_preloads, cpu);
 +              while (kp->nr) {
 +                      kmem_cache_free(zcache_objnode_cache,
 +                                      kp->objnodes[kp->nr - 1]);
 +                      kp->objnodes[kp->nr - 1] = NULL;
 +                      kp->nr--;
 +              }
 +              if (kp->obj) {
 +                      kmem_cache_free(zcache_obj_cache, kp->obj);
 +                      kp->obj = NULL;
 +              }
 +              if (kp->flnode) {
 +                      kmem_cache_free(ramster_flnode_cache, kp->flnode);
 +                      kp->flnode = NULL;
 +              }
 +              if (kp->page) {
 +                      free_page((unsigned long)kp->page);
 +                      kp->page = NULL;
 +              }
 +              break;
 +      default:
 +              break;
 +      }
 +      return NOTIFY_OK;
 +}
 +
 +static struct notifier_block zcache_cpu_notifier_block = {
 +      .notifier_call = zcache_cpu_notifier
 +};
 +
 +#ifdef CONFIG_SYSFS
 +#define ZCACHE_SYSFS_RO(_name) \
 +      static ssize_t zcache_##_name##_show(struct kobject *kobj, \
 +                              struct kobj_attribute *attr, char *buf) \
 +      { \
 +              return sprintf(buf, "%lu\n", zcache_##_name); \
 +      } \
 +      static struct kobj_attribute zcache_##_name##_attr = { \
 +              .attr = { .name = __stringify(_name), .mode = 0444 }, \
 +              .show = zcache_##_name##_show, \
 +      }
 +
 +#define ZCACHE_SYSFS_RO_ATOMIC(_name) \
 +      static ssize_t zcache_##_name##_show(struct kobject *kobj, \
 +                              struct kobj_attribute *attr, char *buf) \
 +      { \
 +          return sprintf(buf, "%d\n", atomic_read(&zcache_##_name)); \
 +      } \
 +      static struct kobj_attribute zcache_##_name##_attr = { \
 +              .attr = { .name = __stringify(_name), .mode = 0444 }, \
 +              .show = zcache_##_name##_show, \
 +      }
 +
 +#define ZCACHE_SYSFS_RO_CUSTOM(_name, _func) \
 +      static ssize_t zcache_##_name##_show(struct kobject *kobj, \
 +                              struct kobj_attribute *attr, char *buf) \
 +      { \
 +          return _func(buf); \
 +      } \
 +      static struct kobj_attribute zcache_##_name##_attr = { \
 +              .attr = { .name = __stringify(_name), .mode = 0444 }, \
 +              .show = zcache_##_name##_show, \
 +      }
 +
 +ZCACHE_SYSFS_RO(curr_obj_count_max);
 +ZCACHE_SYSFS_RO(curr_objnode_count_max);
 +ZCACHE_SYSFS_RO(flush_total);
 +ZCACHE_SYSFS_RO(flush_found);
 +ZCACHE_SYSFS_RO(flobj_total);
 +ZCACHE_SYSFS_RO(flobj_found);
 +ZCACHE_SYSFS_RO(failed_eph_puts);
 +ZCACHE_SYSFS_RO(nonactive_puts);
 +ZCACHE_SYSFS_RO(failed_pers_puts);
 +ZCACHE_SYSFS_RO(zbud_curr_zbytes);
 +ZCACHE_SYSFS_RO(zbud_cumul_zpages);
 +ZCACHE_SYSFS_RO(zbud_cumul_zbytes);
 +ZCACHE_SYSFS_RO(zbud_buddied_count);
 +ZCACHE_SYSFS_RO(evicted_raw_pages);
 +ZCACHE_SYSFS_RO(evicted_unbuddied_pages);
 +ZCACHE_SYSFS_RO(evicted_buddied_pages);
 +ZCACHE_SYSFS_RO(failed_get_free_pages);
 +ZCACHE_SYSFS_RO(failed_alloc);
 +ZCACHE_SYSFS_RO(put_to_flush);
 +ZCACHE_SYSFS_RO(compress_poor);
 +ZCACHE_SYSFS_RO(mean_compress_poor);
 +ZCACHE_SYSFS_RO(policy_percent_exceeded);
 +ZCACHE_SYSFS_RO_ATOMIC(zbud_curr_raw_pages);
 +ZCACHE_SYSFS_RO_ATOMIC(zbud_curr_zpages);
 +ZCACHE_SYSFS_RO_ATOMIC(curr_obj_count);
 +ZCACHE_SYSFS_RO_ATOMIC(curr_objnode_count);
 +ZCACHE_SYSFS_RO_CUSTOM(zbud_unbuddied_list_counts,
 +                      zbud_show_unbuddied_list_counts);
 +ZCACHE_SYSFS_RO_CUSTOM(zbud_cumul_chunk_counts,
 +                      zbud_show_cumul_chunk_counts);
 +ZCACHE_SYSFS_RO_CUSTOM(zv_curr_dist_counts,
 +                      zv_curr_dist_counts_show);
 +ZCACHE_SYSFS_RO_CUSTOM(zv_cumul_dist_counts,
 +                      zv_cumul_dist_counts_show);
 +
 +static struct attribute *zcache_attrs[] = {
 +      &zcache_curr_obj_count_attr.attr,
 +      &zcache_curr_obj_count_max_attr.attr,
 +      &zcache_curr_objnode_count_attr.attr,
 +      &zcache_curr_objnode_count_max_attr.attr,
 +      &zcache_flush_total_attr.attr,
 +      &zcache_flobj_total_attr.attr,
 +      &zcache_flush_found_attr.attr,
 +      &zcache_flobj_found_attr.attr,
 +      &zcache_failed_eph_puts_attr.attr,
 +      &zcache_nonactive_puts_attr.attr,
 +      &zcache_failed_pers_puts_attr.attr,
 +      &zcache_policy_percent_exceeded_attr.attr,
 +      &zcache_compress_poor_attr.attr,
 +      &zcache_mean_compress_poor_attr.attr,
 +      &zcache_zbud_curr_raw_pages_attr.attr,
 +      &zcache_zbud_curr_zpages_attr.attr,
 +      &zcache_zbud_curr_zbytes_attr.attr,
 +      &zcache_zbud_cumul_zpages_attr.attr,
 +      &zcache_zbud_cumul_zbytes_attr.attr,
 +      &zcache_zbud_buddied_count_attr.attr,
 +      &zcache_evicted_raw_pages_attr.attr,
 +      &zcache_evicted_unbuddied_pages_attr.attr,
 +      &zcache_evicted_buddied_pages_attr.attr,
 +      &zcache_failed_get_free_pages_attr.attr,
 +      &zcache_failed_alloc_attr.attr,
 +      &zcache_put_to_flush_attr.attr,
 +      &zcache_zbud_unbuddied_list_counts_attr.attr,
 +      &zcache_zbud_cumul_chunk_counts_attr.attr,
 +      &zcache_zv_curr_dist_counts_attr.attr,
 +      &zcache_zv_cumul_dist_counts_attr.attr,
 +      &zcache_zv_max_zsize_attr.attr,
 +      &zcache_zv_max_mean_zsize_attr.attr,
 +      &zcache_zv_page_count_policy_percent_attr.attr,
 +      NULL,
 +};
 +
 +static struct attribute_group zcache_attr_group = {
 +      .attrs = zcache_attrs,
 +      .name = "zcache",
 +};
 +
 +#define RAMSTER_SYSFS_RO(_name) \
 +      static ssize_t ramster_##_name##_show(struct kobject *kobj, \
 +                              struct kobj_attribute *attr, char *buf) \
 +      { \
 +              return sprintf(buf, "%lu\n", ramster_##_name); \
 +      } \
 +      static struct kobj_attribute ramster_##_name##_attr = { \
 +              .attr = { .name = __stringify(_name), .mode = 0444 }, \
 +              .show = ramster_##_name##_show, \
 +      }
 +
 +#define RAMSTER_SYSFS_RW(_name) \
 +      static ssize_t ramster_##_name##_show(struct kobject *kobj, \
 +                              struct kobj_attribute *attr, char *buf) \
 +      { \
 +              return sprintf(buf, "%lu\n", ramster_##_name); \
 +      } \
 +      static ssize_t ramster_##_name##_store(struct kobject *kobj, \
 +              struct kobj_attribute *attr, const char *buf, size_t count) \
 +      { \
 +              int err; \
 +              unsigned long enable; \
 +              err = kstrtoul(buf, 10, &enable); \
 +              if (err) \
 +                      return -EINVAL; \
 +              ramster_##_name = enable; \
 +              return count; \
 +      } \
 +      static struct kobj_attribute ramster_##_name##_attr = { \
 +              .attr = { .name = __stringify(_name), .mode = 0644 }, \
 +              .show = ramster_##_name##_show, \
 +              .store = ramster_##_name##_store, \
 +      }
 +
 +#define RAMSTER_SYSFS_RO_ATOMIC(_name) \
 +      static ssize_t ramster_##_name##_show(struct kobject *kobj, \
 +                              struct kobj_attribute *attr, char *buf) \
 +      { \
 +          return sprintf(buf, "%d\n", atomic_read(&ramster_##_name)); \
 +      } \
 +      static struct kobj_attribute ramster_##_name##_attr = { \
 +              .attr = { .name = __stringify(_name), .mode = 0444 }, \
 +              .show = ramster_##_name##_show, \
 +      }
 +
 +RAMSTER_SYSFS_RO(interface_revision);
 +RAMSTER_SYSFS_RO_ATOMIC(remote_pers_pages);
 +RAMSTER_SYSFS_RW(pers_remotify_enable);
 +RAMSTER_SYSFS_RW(eph_remotify_enable);
 +RAMSTER_SYSFS_RO(eph_pages_remoted);
 +RAMSTER_SYSFS_RO(eph_pages_remote_failed);
 +RAMSTER_SYSFS_RO(pers_pages_remoted);
 +RAMSTER_SYSFS_RO(pers_pages_remote_failed);
 +RAMSTER_SYSFS_RO(pers_pages_remote_nomem);
 +RAMSTER_SYSFS_RO(remote_pages_flushed);
 +RAMSTER_SYSFS_RO(remote_page_flushes_failed);
 +RAMSTER_SYSFS_RO(remote_objects_flushed);
 +RAMSTER_SYSFS_RO(remote_object_flushes_failed);
 +RAMSTER_SYSFS_RO(remote_eph_pages_succ_get);
 +RAMSTER_SYSFS_RO(remote_eph_pages_unsucc_get);
 +RAMSTER_SYSFS_RO(remote_pers_pages_succ_get);
 +RAMSTER_SYSFS_RO(remote_pers_pages_unsucc_get);
 +RAMSTER_SYSFS_RO_ATOMIC(foreign_eph_pampd_count);
 +RAMSTER_SYSFS_RO(foreign_eph_pampd_count_max);
 +RAMSTER_SYSFS_RO_ATOMIC(foreign_pers_pampd_count);
 +RAMSTER_SYSFS_RO(foreign_pers_pampd_count_max);
 +RAMSTER_SYSFS_RO_ATOMIC(curr_flnode_count);
 +RAMSTER_SYSFS_RO(curr_flnode_count_max);
 +
 +#define MANUAL_NODES 8
 +static bool ramster_nodes_manual_up[MANUAL_NODES];
 +static ssize_t ramster_manual_node_up_show(struct kobject *kobj,
 +                              struct kobj_attribute *attr, char *buf)
 +{
 +      int i;
 +      char *p = buf;
 +      for (i = 0; i < MANUAL_NODES; i++)
 +              if (ramster_nodes_manual_up[i])
 +                      p += sprintf(p, "%d ", i);
 +      p += sprintf(p, "\n");
 +      return p - buf;
 +}
 +
 +static ssize_t ramster_manual_node_up_store(struct kobject *kobj,
 +              struct kobj_attribute *attr, const char *buf, size_t count)
 +{
 +      int err;
 +      unsigned long node_num;
 +
 +      err = kstrtoul(buf, 10, &node_num);
 +      if (err) {
 +              pr_err("ramster: bad strtoul?\n");
 +              return -EINVAL;
 +      }
 +      if (node_num >= MANUAL_NODES) {
 +              pr_err("ramster: bad node_num=%lu?\n", node_num);
 +              return -EINVAL;
 +      }
 +      if (ramster_nodes_manual_up[node_num]) {
 +              pr_err("ramster: node %d already up, ignoring\n",
 +                                                      (int)node_num);
 +      } else {
 +              ramster_nodes_manual_up[node_num] = true;
 +              r2net_hb_node_up_manual((int)node_num);
 +      }
 +      return count;
 +}
 +
 +static struct kobj_attribute ramster_manual_node_up_attr = {
 +      .attr = { .name = "manual_node_up", .mode = 0644 },
 +      .show = ramster_manual_node_up_show,
 +      .store = ramster_manual_node_up_store,
 +};
 +
 +static ssize_t ramster_remote_target_nodenum_show(struct kobject *kobj,
 +                              struct kobj_attribute *attr, char *buf)
 +{
 +      if (ramster_remote_target_nodenum == -1UL)
 +              return sprintf(buf, "unset\n");
 +      else
 +              return sprintf(buf, "%d\n", ramster_remote_target_nodenum);
 +}
 +
 +static ssize_t ramster_remote_target_nodenum_store(struct kobject *kobj,
 +              struct kobj_attribute *attr, const char *buf, size_t count)
 +{
 +      int err;
 +      unsigned long node_num;
 +
 +      err = kstrtoul(buf, 10, &node_num);
 +      if (err) {
 +              pr_err("ramster: bad strtoul?\n");
 +              return -EINVAL;
 +      } else if (node_num == -1UL) {
 +              pr_err("ramster: disabling all remotification, "
 +                      "data may still reside on remote nodes however\n");
 +              return -EINVAL;
 +      } else if (node_num >= MANUAL_NODES) {
 +              pr_err("ramster: bad node_num=%lu?\n", node_num);
 +              return -EINVAL;
 +      } else if (!ramster_nodes_manual_up[node_num]) {
 +              pr_err("ramster: node %d not up, ignoring setting "
 +                      "of remotification target\n", (int)node_num);
 +      } else if (r2net_remote_target_node_set((int)node_num) >= 0) {
 +              pr_info("ramster: node %d set as remotification target\n",
 +                              (int)node_num);
 +              ramster_remote_target_nodenum = (int)node_num;
 +      } else {
 +              pr_err("ramster: bad num to node node_num=%d?\n",
 +                              (int)node_num);
 +              return -EINVAL;
 +      }
 +      return count;
 +}
 +
 +static struct kobj_attribute ramster_remote_target_nodenum_attr = {
 +      .attr = { .name = "remote_target_nodenum", .mode = 0644 },
 +      .show = ramster_remote_target_nodenum_show,
 +      .store = ramster_remote_target_nodenum_store,
 +};
 +
 +
 +static struct attribute *ramster_attrs[] = {
 +      &ramster_interface_revision_attr.attr,
 +      &ramster_pers_remotify_enable_attr.attr,
 +      &ramster_eph_remotify_enable_attr.attr,
 +      &ramster_remote_pers_pages_attr.attr,
 +      &ramster_eph_pages_remoted_attr.attr,
 +      &ramster_eph_pages_remote_failed_attr.attr,
 +      &ramster_pers_pages_remoted_attr.attr,
 +      &ramster_pers_pages_remote_failed_attr.attr,
 +      &ramster_pers_pages_remote_nomem_attr.attr,
 +      &ramster_remote_pages_flushed_attr.attr,
 +      &ramster_remote_page_flushes_failed_attr.attr,
 +      &ramster_remote_objects_flushed_attr.attr,
 +      &ramster_remote_object_flushes_failed_attr.attr,
 +      &ramster_remote_eph_pages_succ_get_attr.attr,
 +      &ramster_remote_eph_pages_unsucc_get_attr.attr,
 +      &ramster_remote_pers_pages_succ_get_attr.attr,
 +      &ramster_remote_pers_pages_unsucc_get_attr.attr,
 +      &ramster_foreign_eph_pampd_count_attr.attr,
 +      &ramster_foreign_eph_pampd_count_max_attr.attr,
 +      &ramster_foreign_pers_pampd_count_attr.attr,
 +      &ramster_foreign_pers_pampd_count_max_attr.attr,
 +      &ramster_curr_flnode_count_attr.attr,
 +      &ramster_curr_flnode_count_max_attr.attr,
 +      &ramster_manual_node_up_attr.attr,
 +      &ramster_remote_target_nodenum_attr.attr,
 +      NULL,
 +};
 +
 +static struct attribute_group ramster_attr_group = {
 +      .attrs = ramster_attrs,
 +      .name = "ramster",
 +};
 +
 +#endif /* CONFIG_SYSFS */
 +/*
 + * When zcache is disabled ("frozen"), pools can be created and destroyed,
 + * but all puts (and thus all other operations that require memory allocation)
 + * must fail.  If zcache is unfrozen, accepts puts, then frozen again,
 + * data consistency requires all puts while frozen to be converted into
 + * flushes.
 + */
 +static bool zcache_freeze;
 +
 +/*
 + * zcache shrinker interface (only useful for ephemeral pages, so zbud only)
 + */
 +static int shrink_zcache_memory(struct shrinker *shrink,
 +                              struct shrink_control *sc)
 +{
 +      int ret = -1;
 +      int nr = sc->nr_to_scan;
 +      gfp_t gfp_mask = sc->gfp_mask;
 +
 +      if (nr >= 0) {
 +              if (!(gfp_mask & __GFP_FS))
 +                      /* does this case really need to be skipped? */
 +                      goto out;
 +              zbud_evict_pages(nr);
 +      }
 +      ret = (int)atomic_read(&zcache_zbud_curr_raw_pages);
 +out:
 +      return ret;
 +}
 +
 +static struct shrinker zcache_shrinker = {
 +      .shrink = shrink_zcache_memory,
 +      .seeks = DEFAULT_SEEKS,
 +};
 +
 +/*
 + * zcache shims between cleancache/frontswap ops and tmem
 + */
 +
 +int zcache_put(int cli_id, int pool_id, struct tmem_oid *oidp,
 +                      uint32_t index, char *data, size_t size,
 +                      bool raw, int ephemeral)
 +{
 +      struct tmem_pool *pool;
 +      int ret = -1;
 +
 +      BUG_ON(!irqs_disabled());
 +      pool = zcache_get_pool_by_id(cli_id, pool_id);
 +      if (unlikely(pool == NULL))
 +              goto out;
 +      if (!zcache_freeze && zcache_do_preload(pool) == 0) {
 +              /* preload does preempt_disable on success */
 +              ret = tmem_put(pool, oidp, index, data, size, raw, ephemeral);
 +              if (ret < 0) {
 +                      if (is_ephemeral(pool))
 +                              zcache_failed_eph_puts++;
 +                      else
 +                              zcache_failed_pers_puts++;
 +              }
 +              zcache_put_pool(pool);
 +              preempt_enable_no_resched();
 +      } else {
 +              zcache_put_to_flush++;
 +              if (atomic_read(&pool->obj_count) > 0)
 +                      /* the put fails whether the flush succeeds or not */
 +                      (void)tmem_flush_page(pool, oidp, index);
 +              zcache_put_pool(pool);
 +      }
 +out:
 +      return ret;
 +}
 +
 +int zcache_get(int cli_id, int pool_id, struct tmem_oid *oidp,
 +                      uint32_t index, char *data, size_t *sizep,
 +                      bool raw, int get_and_free)
 +{
 +      struct tmem_pool *pool;
 +      int ret = -1;
 +      bool eph;
 +
 +      if (!raw) {
 +              BUG_ON(irqs_disabled());
 +              BUG_ON(in_softirq());
 +      }
 +      pool = zcache_get_pool_by_id(cli_id, pool_id);
 +      eph = is_ephemeral(pool);
 +      if (likely(pool != NULL)) {
 +              if (atomic_read(&pool->obj_count) > 0)
 +                      ret = tmem_get(pool, oidp, index, data, sizep,
 +                                      raw, get_and_free);
 +              zcache_put_pool(pool);
 +      }
 +      WARN_ONCE((!eph && (ret != 0)), "zcache_get fails on persistent pool, "
 +                        "bad things are very likely to happen soon\n");
 +#ifdef RAMSTER_TESTING
 +      if (ret != 0 && ret != -1 && !(ret == -EINVAL && is_ephemeral(pool)))
 +              pr_err("TESTING zcache_get tmem_get returns ret=%d\n", ret);
 +#endif
 +      if (ret == -EAGAIN)
 +              BUG(); /* FIXME... don't need this anymore??? let's ensure */
 +      return ret;
 +}
 +
 +int zcache_flush(int cli_id, int pool_id,
 +                              struct tmem_oid *oidp, uint32_t index)
 +{
 +      struct tmem_pool *pool;
 +      int ret = -1;
 +      unsigned long flags;
 +
 +      local_irq_save(flags);
 +      zcache_flush_total++;
 +      pool = zcache_get_pool_by_id(cli_id, pool_id);
 +      ramster_do_preload_flnode_only(pool);
 +      if (likely(pool != NULL)) {
 +              if (atomic_read(&pool->obj_count) > 0)
 +                      ret = tmem_flush_page(pool, oidp, index);
 +              zcache_put_pool(pool);
 +      }
 +      if (ret >= 0)
 +              zcache_flush_found++;
 +      local_irq_restore(flags);
 +      return ret;
 +}
 +
 +int zcache_flush_object(int cli_id, int pool_id, struct tmem_oid *oidp)
 +{
 +      struct tmem_pool *pool;
 +      int ret = -1;
 +      unsigned long flags;
 +
 +      local_irq_save(flags);
 +      zcache_flobj_total++;
 +      pool = zcache_get_pool_by_id(cli_id, pool_id);
 +      ramster_do_preload_flnode_only(pool);
 +      if (likely(pool != NULL)) {
 +              if (atomic_read(&pool->obj_count) > 0)
 +                      ret = tmem_flush_object(pool, oidp);
 +              zcache_put_pool(pool);
 +      }
 +      if (ret >= 0)
 +              zcache_flobj_found++;
 +      local_irq_restore(flags);
 +      return ret;
 +}
 +
 +int zcache_client_destroy_pool(int cli_id, int pool_id)
 +{
 +      struct tmem_pool *pool = NULL;
 +      struct zcache_client *cli = NULL;
 +      int ret = -1;
 +
 +      if (pool_id < 0)
 +              goto out;
 +      if (cli_id == LOCAL_CLIENT)
 +              cli = &zcache_host;
 +      else if ((unsigned int)cli_id < MAX_CLIENTS)
 +              cli = &zcache_clients[cli_id];
 +      if (cli == NULL)
 +              goto out;
 +      atomic_inc(&cli->refcount);
 +      pool = cli->tmem_pools[pool_id];
 +      if (pool == NULL)
 +              goto out;
 +      cli->tmem_pools[pool_id] = NULL;
 +      /* wait for pool activity on other cpus to quiesce */
 +      while (atomic_read(&pool->refcount) != 0)
 +              ;
 +      atomic_dec(&cli->refcount);
 +      local_bh_disable();
 +      ret = tmem_destroy_pool(pool);
 +      local_bh_enable();
 +      kfree(pool);
 +      pr_info("ramster: destroyed pool id=%d cli_id=%d\n", pool_id, cli_id);
 +out:
 +      return ret;
 +}
 +
 +static int zcache_destroy_pool(int pool_id)
 +{
 +      return zcache_client_destroy_pool(LOCAL_CLIENT, pool_id);
 +}
 +
 +int zcache_new_pool(uint16_t cli_id, uint32_t flags)
 +{
 +      int poolid = -1;
 +      struct tmem_pool *pool;
 +      struct zcache_client *cli = NULL;
 +
 +      if (cli_id == LOCAL_CLIENT)
 +              cli = &zcache_host;
 +      else if ((unsigned int)cli_id < MAX_CLIENTS)
 +              cli = &zcache_clients[cli_id];
 +      if (cli == NULL)
 +              goto out;
 +      atomic_inc(&cli->refcount);
 +      pool = kmalloc(sizeof(struct tmem_pool), GFP_ATOMIC);
 +      if (pool == NULL) {
 +              pr_info("ramster: pool creation failed: out of memory\n");
 +              goto out;
 +      }
 +
 +      for (poolid = 0; poolid < MAX_POOLS_PER_CLIENT; poolid++)
 +              if (cli->tmem_pools[poolid] == NULL)
 +                      break;
 +      if (poolid >= MAX_POOLS_PER_CLIENT) {
 +              pr_info("ramster: pool creation failed: max exceeded\n");
 +              kfree(pool);
 +              poolid = -1;
 +              goto out;
 +      }
 +      atomic_set(&pool->refcount, 0);
 +      pool->client = cli;
 +      pool->pool_id = poolid;
 +      tmem_new_pool(pool, flags);
 +      cli->tmem_pools[poolid] = pool;
 +      if (cli_id == LOCAL_CLIENT)
 +              pr_info("ramster: created %s tmem pool, id=%d, local client\n",
 +                      flags & TMEM_POOL_PERSIST ? "persistent" : "ephemeral",
 +                      poolid);
 +      else
 +              pr_info("ramster: created %s tmem pool, id=%d, client=%d\n",
 +                      flags & TMEM_POOL_PERSIST ? "persistent" : "ephemeral",
 +                      poolid, cli_id);
 +out:
 +      if (cli != NULL)
 +              atomic_dec(&cli->refcount);
 +      return poolid;
 +}
 +
 +static int zcache_local_new_pool(uint32_t flags)
 +{
 +      return zcache_new_pool(LOCAL_CLIENT, flags);
 +}
 +
 +int zcache_autocreate_pool(int cli_id, int pool_id, bool ephemeral)
 +{
 +      struct tmem_pool *pool;
 +      struct zcache_client *cli = NULL;
 +      uint32_t flags = ephemeral ? 0 : TMEM_POOL_PERSIST;
 +      int ret = -1;
 +
 +      if (cli_id == LOCAL_CLIENT)
 +              goto out;
 +      if (pool_id >= MAX_POOLS_PER_CLIENT)
 +              goto out;
 +      else if ((unsigned int)cli_id < MAX_CLIENTS)
 +              cli = &zcache_clients[cli_id];
 +      if ((ephemeral && !use_cleancache) || (!ephemeral && !use_frontswap))
 +              BUG(); /* FIXME, handle more gracefully later */
 +      if (!cli->allocated) {
 +              if (zcache_new_client(cli_id))
 +                      BUG(); /* FIXME, handle more gracefully later */
 +              cli = &zcache_clients[cli_id];
 +      }
 +      atomic_inc(&cli->refcount);
 +      pool = cli->tmem_pools[pool_id];
 +      if (pool != NULL) {
 +              if (pool->persistent && ephemeral) {
 +                      pr_err("zcache_autocreate_pool: type mismatch\n");
 +                      goto out;
 +              }
 +              ret = 0;
 +              goto out;
 +      }
 +      pool = kmalloc(sizeof(struct tmem_pool), GFP_KERNEL);
 +      if (pool == NULL) {
 +              pr_info("ramster: pool creation failed: out of memory\n");
 +              goto out;
 +      }
 +      atomic_set(&pool->refcount, 0);
 +      pool->client = cli;
 +      pool->pool_id = pool_id;
 +      tmem_new_pool(pool, flags);
 +      cli->tmem_pools[pool_id] = pool;
 +      pr_info("ramster: AUTOcreated %s tmem poolid=%d, for remote client=%d\n",
 +              flags & TMEM_POOL_PERSIST ? "persistent" : "ephemeral",
 +              pool_id, cli_id);
 +      ret = 0;
 +out:
 +      if (cli == NULL)
 +              BUG(); /* FIXME, handle more gracefully later */
 +              /* pr_err("zcache_autocreate_pool: failed\n"); */
 +      if (cli != NULL)
 +              atomic_dec(&cli->refcount);
 +      return ret;
 +}
 +
 +/**********
 + * Two kernel functionalities currently can be layered on top of tmem.
 + * These are "cleancache" which is used as a second-chance cache for clean
 + * page cache pages; and "frontswap" which is used for swap pages
 + * to avoid writes to disk.  A generic "shim" is provided here for each
 + * to translate in-kernel semantics to zcache semantics.
 + */
 +
 +#ifdef CONFIG_CLEANCACHE
 +static void zcache_cleancache_put_page(int pool_id,
 +                                      struct cleancache_filekey key,
 +                                      pgoff_t index, struct page *page)
 +{
 +      u32 ind = (u32) index;
 +      struct tmem_oid oid = *(struct tmem_oid *)&key;
 +
 +#ifdef __PG_WAS_ACTIVE
 +      if (!PageWasActive(page)) {
 +              zcache_nonactive_puts++;
 +              return;
 +      }
 +#endif
 +      if (likely(ind == index)) {
 +              char *kva = page_address(page);
 +
 +              (void)zcache_put(LOCAL_CLIENT, pool_id, &oid, index,
 +                      kva, PAGE_SIZE, 0, 1);
 +      }
 +}
 +
 +static int zcache_cleancache_get_page(int pool_id,
 +                                      struct cleancache_filekey key,
 +                                      pgoff_t index, struct page *page)
 +{
 +      u32 ind = (u32) index;
 +      struct tmem_oid oid = *(struct tmem_oid *)&key;
 +      int ret = -1;
 +
 +      preempt_disable();
 +      if (likely(ind == index)) {
 +              char *kva = page_address(page);
 +              size_t size = PAGE_SIZE;
 +
 +              ret = zcache_get(LOCAL_CLIENT, pool_id, &oid, index,
 +                      kva, &size, 0, 0);
 +#ifdef __PG_WAS_ACTIVE
 +              if (ret == 0)
 +                      SetPageWasActive(page);
 +#endif
 +      }
 +      preempt_enable();
 +      return ret;
 +}
 +
 +static void zcache_cleancache_flush_page(int pool_id,
 +                                      struct cleancache_filekey key,
 +                                      pgoff_t index)
 +{
 +      u32 ind = (u32) index;
 +      struct tmem_oid oid = *(struct tmem_oid *)&key;
 +
 +      if (likely(ind == index))
 +              (void)zcache_flush(LOCAL_CLIENT, pool_id, &oid, ind);
 +}
 +
 +static void zcache_cleancache_flush_inode(int pool_id,
 +                                      struct cleancache_filekey key)
 +{
 +      struct tmem_oid oid = *(struct tmem_oid *)&key;
 +
 +      (void)zcache_flush_object(LOCAL_CLIENT, pool_id, &oid);
 +}
 +
 +static void zcache_cleancache_flush_fs(int pool_id)
 +{
 +      if (pool_id >= 0)
 +              (void)zcache_destroy_pool(pool_id);
 +}
 +
 +static int zcache_cleancache_init_fs(size_t pagesize)
 +{
 +      BUG_ON(sizeof(struct cleancache_filekey) !=
 +                              sizeof(struct tmem_oid));
 +      BUG_ON(pagesize != PAGE_SIZE);
 +      return zcache_local_new_pool(0);
 +}
 +
 +static int zcache_cleancache_init_shared_fs(char *uuid, size_t pagesize)
 +{
 +      /* shared pools are unsupported and map to private */
 +      BUG_ON(sizeof(struct cleancache_filekey) !=
 +                              sizeof(struct tmem_oid));
 +      BUG_ON(pagesize != PAGE_SIZE);
 +      return zcache_local_new_pool(0);
 +}
 +
 +static struct cleancache_ops zcache_cleancache_ops = {
 +      .put_page = zcache_cleancache_put_page,
 +      .get_page = zcache_cleancache_get_page,
 +      .invalidate_page = zcache_cleancache_flush_page,
 +      .invalidate_inode = zcache_cleancache_flush_inode,
 +      .invalidate_fs = zcache_cleancache_flush_fs,
 +      .init_shared_fs = zcache_cleancache_init_shared_fs,
 +      .init_fs = zcache_cleancache_init_fs
 +};
 +
 +struct cleancache_ops zcache_cleancache_register_ops(void)
 +{
 +      struct cleancache_ops old_ops =
 +              cleancache_register_ops(&zcache_cleancache_ops);
 +
 +      return old_ops;
 +}
 +#endif
 +
 +#ifdef CONFIG_FRONTSWAP
 +/* a single tmem poolid is used for all frontswap "types" (swapfiles) */
 +static int zcache_frontswap_poolid = -1;
 +
 +/*
 + * Swizzling increases objects per swaptype, increasing tmem concurrency
 + * for heavy swaploads.  Later, larger nr_cpus -> larger SWIZ_BITS
 + */
 +#define SWIZ_BITS             8
 +#define SWIZ_MASK             ((1 << SWIZ_BITS) - 1)
 +#define _oswiz(_type, _ind)   ((_type << SWIZ_BITS) | (_ind & SWIZ_MASK))
 +#define iswiz(_ind)           (_ind >> SWIZ_BITS)
 +
 +static inline struct tmem_oid oswiz(unsigned type, u32 ind)
 +{
 +      struct tmem_oid oid = { .oid = { 0 } };
 +      oid.oid[0] = _oswiz(type, ind);
 +      return oid;
 +}
 +
 +static int zcache_frontswap_put_page(unsigned type, pgoff_t offset,
 +                                 struct page *page)
 +{
 +      u64 ind64 = (u64)offset;
 +      u32 ind = (u32)offset;
 +      struct tmem_oid oid = oswiz(type, ind);
 +      int ret = -1;
 +      unsigned long flags;
 +      char *kva;
 +
 +      BUG_ON(!PageLocked(page));
 +      if (likely(ind64 == ind)) {
 +              local_irq_save(flags);
 +              kva = page_address(page);
 +              ret = zcache_put(LOCAL_CLIENT, zcache_frontswap_poolid,
 +                              &oid, iswiz(ind), kva, PAGE_SIZE, 0, 0);
 +              local_irq_restore(flags);
 +      }
 +      return ret;
 +}
 +
 +/* returns 0 if the page was successfully gotten from frontswap, -1 if
 + * was not present (should never happen!) */
 +static int zcache_frontswap_get_page(unsigned type, pgoff_t offset,
 +                                 struct page *page)
 +{
 +      u64 ind64 = (u64)offset;
 +      u32 ind = (u32)offset;
 +      struct tmem_oid oid = oswiz(type, ind);
 +      int ret = -1;
 +
 +      preempt_disable(); /* FIXME, remove this? */
 +      BUG_ON(!PageLocked(page));
 +      if (likely(ind64 == ind)) {
 +              char *kva = page_address(page);
 +              size_t size = PAGE_SIZE;
 +
 +              ret = zcache_get(LOCAL_CLIENT, zcache_frontswap_poolid,
 +                                      &oid, iswiz(ind), kva, &size, 0, -1);
 +      }
 +      preempt_enable(); /* FIXME, remove this? */
 +      return ret;
 +}
 +
 +/* flush a single page from frontswap */
 +static void zcache_frontswap_flush_page(unsigned type, pgoff_t offset)
 +{
 +      u64 ind64 = (u64)offset;
 +      u32 ind = (u32)offset;
 +      struct tmem_oid oid = oswiz(type, ind);
 +
 +      if (likely(ind64 == ind))
 +              (void)zcache_flush(LOCAL_CLIENT, zcache_frontswap_poolid,
 +                                      &oid, iswiz(ind));
 +}
 +
 +/* flush all pages from the passed swaptype */
 +static void zcache_frontswap_flush_area(unsigned type)
 +{
 +      struct tmem_oid oid;
 +      int ind;
 +
 +      for (ind = SWIZ_MASK; ind >= 0; ind--) {
 +              oid = oswiz(type, ind);
 +              (void)zcache_flush_object(LOCAL_CLIENT,
 +                                              zcache_frontswap_poolid, &oid);
 +      }
 +}
 +
 +static void zcache_frontswap_init(unsigned ignored)
 +{
 +      /* a single tmem poolid is used for all frontswap "types" (swapfiles) */
 +      if (zcache_frontswap_poolid < 0)
 +              zcache_frontswap_poolid =
 +                              zcache_local_new_pool(TMEM_POOL_PERSIST);
 +}
 +
 +static struct frontswap_ops zcache_frontswap_ops = {
 +      .put_page = zcache_frontswap_put_page,
 +      .get_page = zcache_frontswap_get_page,
 +      .invalidate_page = zcache_frontswap_flush_page,
 +      .invalidate_area = zcache_frontswap_flush_area,
 +      .init = zcache_frontswap_init
 +};
 +
 +struct frontswap_ops zcache_frontswap_register_ops(void)
 +{
 +      struct frontswap_ops old_ops =
 +              frontswap_register_ops(&zcache_frontswap_ops);
 +
 +      return old_ops;
 +}
 +#endif
 +
 +/*
 + * frontswap selfshrinking
 + */
 +
 +#ifdef CONFIG_FRONTSWAP
 +/* In HZ, controls frequency of worker invocation. */
 +static unsigned int selfshrink_interval __read_mostly = 5;
 +
 +static void selfshrink_process(struct work_struct *work);
 +static DECLARE_DELAYED_WORK(selfshrink_worker, selfshrink_process);
 +
 +/* Enable/disable with sysfs. */
 +static bool frontswap_selfshrinking __read_mostly;
 +
 +/* Enable/disable with kernel boot option. */
 +static bool use_frontswap_selfshrink __initdata = true;
 +
 +/*
 + * The default values for the following parameters were deemed reasonable
 + * by experimentation, may be workload-dependent, and can all be
 + * adjusted via sysfs.
 + */
 +
 +/* Control rate for frontswap shrinking. Higher hysteresis is slower. */
 +static unsigned int frontswap_hysteresis __read_mostly = 20;
 +
 +/*
 + * Number of selfshrink worker invocations to wait before observing that
 + * frontswap selfshrinking should commence. Note that selfshrinking does
 + * not use a separate worker thread.
 + */
 +static unsigned int frontswap_inertia __read_mostly = 3;
 +
 +/* Countdown to next invocation of frontswap_shrink() */
 +static unsigned long frontswap_inertia_counter;
 +
 +/*
 + * Invoked by the selfshrink worker thread, uses current number of pages
 + * in frontswap (frontswap_curr_pages()), previous status, and control
 + * values (hysteresis and inertia) to determine if frontswap should be
 + * shrunk and what the new frontswap size should be.  Note that
 + * frontswap_shrink is essentially a partial swapoff that immediately
 + * transfers pages from the "swap device" (frontswap) back into kernel
 + * RAM; despite the name, frontswap "shrinking" is very different from
 + * the "shrinker" interface used by the kernel MM subsystem to reclaim
 + * memory.
 + */
 +static void frontswap_selfshrink(void)
 +{
 +      static unsigned long cur_frontswap_pages;
 +      static unsigned long last_frontswap_pages;
 +      static unsigned long tgt_frontswap_pages;
 +
 +      last_frontswap_pages = cur_frontswap_pages;
 +      cur_frontswap_pages = frontswap_curr_pages();
 +      if (!cur_frontswap_pages ||
 +                      (cur_frontswap_pages > last_frontswap_pages)) {
 +              frontswap_inertia_counter = frontswap_inertia;
 +              return;
 +      }
 +      if (frontswap_inertia_counter && --frontswap_inertia_counter)
 +              return;
 +      if (cur_frontswap_pages <= frontswap_hysteresis)
 +              tgt_frontswap_pages = 0;
 +      else
 +              tgt_frontswap_pages = cur_frontswap_pages -
 +                      (cur_frontswap_pages / frontswap_hysteresis);
 +      frontswap_shrink(tgt_frontswap_pages);
 +}
 +
 +static int __init ramster_nofrontswap_selfshrink_setup(char *s)
 +{
 +      use_frontswap_selfshrink = false;
 +      return 1;
 +}
 +
 +__setup("noselfshrink", ramster_nofrontswap_selfshrink_setup);
 +
 +static void selfshrink_process(struct work_struct *work)
 +{
 +      if (frontswap_selfshrinking && frontswap_enabled) {
 +              frontswap_selfshrink();
 +              schedule_delayed_work(&selfshrink_worker,
 +                      selfshrink_interval * HZ);
 +      }
 +}
 +
 +static int ramster_enabled;
 +
 +static int __init ramster_selfshrink_init(void)
 +{
 +      frontswap_selfshrinking = ramster_enabled && use_frontswap_selfshrink;
 +      if (frontswap_selfshrinking)
 +              pr_info("ramster: Initializing frontswap "
 +                                      "selfshrinking driver.\n");
 +      else
 +              return -ENODEV;
 +
 +      schedule_delayed_work(&selfshrink_worker, selfshrink_interval * HZ);
 +
 +      return 0;
 +}
 +
 +subsys_initcall(ramster_selfshrink_init);
 +#endif
 +
 +/*
 + * zcache initialization
 + * NOTE FOR NOW ramster MUST BE PROVIDED AS A KERNEL BOOT PARAMETER OR
 + * NOTHING HAPPENS!
 + */
 +
 +static int ramster_enabled;
 +
 +static int __init enable_ramster(char *s)
 +{
 +      ramster_enabled = 1;
 +      return 1;
 +}
 +__setup("ramster", enable_ramster);
 +
 +/* allow independent dynamic disabling of cleancache and frontswap */
 +
 +static int use_cleancache = 1;
 +
 +static int __init no_cleancache(char *s)
 +{
 +      pr_info("INIT no_cleancache called\n");
 +      use_cleancache = 0;
 +      return 1;
 +}
 +
 +/*
 + * FIXME: need to guarantee this gets checked before zcache_init is called
 + * What is the correct way to achieve this?
 + */
 +early_param("nocleancache", no_cleancache);
 +
 +static int use_frontswap = 1;
 +
 +static int __init no_frontswap(char *s)
 +{
 +      pr_info("INIT no_frontswap called\n");
 +      use_frontswap = 0;
 +      return 1;
 +}
 +
 +__setup("nofrontswap", no_frontswap);
 +
 +static int __init zcache_init(void)
 +{
 +      int ret = 0;
 +
 +#ifdef CONFIG_SYSFS
 +      ret = sysfs_create_group(mm_kobj, &zcache_attr_group);
 +      ret = sysfs_create_group(mm_kobj, &ramster_attr_group);
 +      if (ret) {
 +              pr_err("ramster: can't create sysfs\n");
 +              goto out;
 +      }
 +#endif /* CONFIG_SYSFS */
 +#if defined(CONFIG_CLEANCACHE) || defined(CONFIG_FRONTSWAP)
 +      if (ramster_enabled) {
 +              unsigned int cpu;
 +
 +              (void)r2net_register_handlers();
 +              tmem_register_hostops(&zcache_hostops);
 +              tmem_register_pamops(&zcache_pamops);
 +              ret = register_cpu_notifier(&zcache_cpu_notifier_block);
 +              if (ret) {
 +                      pr_err("ramster: can't register cpu notifier\n");
 +                      goto out;
 +              }
 +              for_each_online_cpu(cpu) {
 +                      void *pcpu = (void *)(long)cpu;
 +                      zcache_cpu_notifier(&zcache_cpu_notifier_block,
 +                              CPU_UP_PREPARE, pcpu);
 +              }
 +      }
 +      zcache_objnode_cache = kmem_cache_create("zcache_objnode",
 +                              sizeof(struct tmem_objnode), 0, 0, NULL);
 +      zcache_obj_cache = kmem_cache_create("zcache_obj",
 +                              sizeof(struct tmem_obj), 0, 0, NULL);
 +      ramster_flnode_cache = kmem_cache_create("ramster_flnode",
 +                              sizeof(struct flushlist_node), 0, 0, NULL);
 +#endif
 +#ifdef CONFIG_CLEANCACHE
 +      pr_info("INIT ramster_enabled=%d use_cleancache=%d\n",
 +                                      ramster_enabled, use_cleancache);
 +      if (ramster_enabled && use_cleancache) {
 +              struct cleancache_ops old_ops;
 +
 +              zbud_init();
 +              register_shrinker(&zcache_shrinker);
 +              old_ops = zcache_cleancache_register_ops();
 +              pr_info("ramster: cleancache enabled using kernel "
 +                      "transcendent memory and compression buddies\n");
 +              if (old_ops.init_fs != NULL)
 +                      pr_warning("ramster: cleancache_ops overridden");
 +      }
 +#endif
 +#ifdef CONFIG_FRONTSWAP
 +      pr_info("INIT ramster_enabled=%d use_frontswap=%d\n",
 +                                      ramster_enabled, use_frontswap);
 +      if (ramster_enabled && use_frontswap) {
 +              struct frontswap_ops old_ops;
 +
 +              zcache_new_client(LOCAL_CLIENT);
 +              old_ops = zcache_frontswap_register_ops();
 +              pr_info("ramster: frontswap enabled using kernel "
 +                      "transcendent memory and xvmalloc\n");
 +              if (old_ops.init != NULL)
 +                      pr_warning("ramster: frontswap_ops overridden");
 +      }
 +      if (ramster_enabled && (use_frontswap || use_cleancache))
 +              ramster_remotify_init();
 +#endif
 +out:
 +      return ret;
 +}
 +
 +module_init(zcache_init)
@@@ -455,14 -421,13 +455,14 @@@ static int zbud_decompress(struct page 
        }
        ASSERT_SENTINEL(zh, ZBH);
        BUG_ON(zh->size == 0 || zh->size > zbud_max_buddy_size());
-       to_va = kmap_atomic(page, KM_USER0);
+       to_va = kmap_atomic(page);
        size = zh->size;
        from_va = zbud_data(zh, size);
 -      ret = lzo1x_decompress_safe(from_va, size, to_va, &out_len);
 -      BUG_ON(ret != LZO_E_OK);
 +      ret = zcache_comp_op(ZCACHE_COMPOP_DECOMPRESS, from_va, size,
 +                              to_va, &out_len);
 +      BUG_ON(ret);
        BUG_ON(out_len != PAGE_SIZE);
-       kunmap_atomic(to_va, KM_USER0);
+       kunmap_atomic(to_va);
  out:
        spin_unlock(&zbpg->lock);
        return ret;
@@@ -743,22 -708,21 +743,22 @@@ static void zv_free(struct zs_pool *poo
        local_irq_restore(flags);
  }
  
 -static void zv_decompress(struct page *page, struct zv_hdr *zv)
 +static void zv_decompress(struct page *page, void *handle)
  {
 -      size_t clen = PAGE_SIZE;
 +      unsigned int clen = PAGE_SIZE;
        char *to_va;
 -      unsigned size;
        int ret;
 +      struct zv_hdr *zv;
  
 +      zv = zs_map_object(zcache_host.zspool, handle);
 +      BUG_ON(zv->size == 0);
        ASSERT_SENTINEL(zv, ZVH);
-       to_va = kmap_atomic(page, KM_USER0);
 -      size = xv_get_object_size(zv) - sizeof(*zv);
 -      BUG_ON(size == 0);
+       to_va = kmap_atomic(page);
 -      ret = lzo1x_decompress_safe((char *)zv + sizeof(*zv),
 -                                      size, to_va, &clen);
 +      ret = zcache_comp_op(ZCACHE_COMPOP_DECOMPRESS, (char *)zv + sizeof(*zv),
 +                              zv->size, to_va, &clen);
-       kunmap_atomic(to_va, KM_USER0);
+       kunmap_atomic(to_va);
 -      BUG_ON(ret != LZO_E_OK);
 +      zs_unmap_object(zcache_host.zspool, handle);
 +      BUG_ON(ret);
        BUG_ON(clen != PAGE_SIZE);
  }
  
@@@ -1331,16 -1297,15 +1331,16 @@@ static int zcache_compress(struct page 
        char *from_va;
  
        BUG_ON(!irqs_disabled());
 -      if (unlikely(dmem == NULL || wmem == NULL))
 -              goto out;  /* no buffer, so can't compress */
 +      if (unlikely(dmem == NULL))
 +              goto out;  /* no buffer or no compressor so can't compress */
 +      *out_len = PAGE_SIZE << ZCACHE_DSTMEM_ORDER;
-       from_va = kmap_atomic(from, KM_USER0);
+       from_va = kmap_atomic(from);
        mb();
 -      ret = lzo1x_1_compress(from_va, PAGE_SIZE, dmem, out_len, wmem);
 -      BUG_ON(ret != LZO_E_OK);
 +      ret = zcache_comp_op(ZCACHE_COMPOP_COMPRESS, from_va, PAGE_SIZE, dmem,
 +                              out_len);
 +      BUG_ON(ret);
        *out_va = dmem;
-       kunmap_atomic(from_va, KM_USER0);
+       kunmap_atomic(from_va);
        ret = 1;
  out:
        return ret;
@@@ -188,12 -195,12 +188,12 @@@ static void handle_uncompressed_page(st
        struct page *page = bvec->bv_page;
        unsigned char *user_mem, *cmem;
  
-       user_mem = kmap_atomic(page, KM_USER0);
-       cmem = kmap_atomic(zram->table[index].handle, KM_USER1);
+       user_mem = kmap_atomic(page);
 -      cmem = kmap_atomic(zram->table[index].page);
++      cmem = kmap_atomic(zram->table[index].handle);
  
        memcpy(user_mem + bvec->bv_offset, cmem + offset, bvec->bv_len);
-       kunmap_atomic(cmem, KM_USER1);
-       kunmap_atomic(user_mem, KM_USER0);
+       kunmap_atomic(cmem);
+       kunmap_atomic(user_mem);
  
        flush_dcache_page(page);
  }
@@@ -259,8 -267,8 +259,8 @@@ static int zram_bvec_read(struct zram *
                kfree(uncmem);
        }
  
 -      kunmap_atomic(cmem);
 +      zs_unmap_object(zram->mem_pool, zram->table[index].handle);
-       kunmap_atomic(user_mem, KM_USER0);
+       kunmap_atomic(user_mem);
  
        /* Should NEVER happen. Return bio error if it does. */
        if (unlikely(ret != LZO_E_OK)) {
@@@ -399,9 -407,8 +399,9 @@@ static int zram_bvec_write(struct zram 
                store_offset = 0;
                zram_set_flag(zram, index, ZRAM_UNCOMPRESSED);
                zram_stat_inc(&zram->stats.pages_expand);
 -              zram->table[index].page = page_store;
 +              handle = page_store;
-               src = kmap_atomic(page, KM_USER0);
-               cmem = kmap_atomic(page_store, KM_USER1);
+               src = kmap_atomic(page);
++              cmem = kmap_atomic(page_store);
                goto memstore;
        }
  
@@@ -426,15 -438,9 +426,15 @@@ memstore
  
        memcpy(cmem, src, clen);
  
 -      kunmap_atomic(cmem);
 -      if (unlikely(zram_test_flag(zram, index, ZRAM_UNCOMPRESSED)))
 +      if (unlikely(zram_test_flag(zram, index, ZRAM_UNCOMPRESSED))) {
-               kunmap_atomic(cmem, KM_USER1);
-               kunmap_atomic(src, KM_USER0);
++              kunmap_atomic(cmem);
+               kunmap_atomic(src);
 +      } else {
 +              zs_unmap_object(zram->mem_pool, handle);
 +      }
 +
 +      zram->table[index].handle = handle;
 +      zram->table[index].size = clen;
  
        /* Update stats */
        zram_stat64_add(zram, &zram->stats.compr_size, clen);
diff --cc fs/exec.c
Simple merge
diff --cc fs/namei.c
Simple merge
Simple merge
Simple merge