* Processor and Memory placement constraints for sets of tasks.
*
* Copyright (C) 2003 BULL SA.
- * Copyright (C) 2004 Silicon Graphics, Inc.
+ * Copyright (C) 2004-2007 Silicon Graphics, Inc.
+ * Copyright (C) 2006 Google, Inc
*
* Portions derived from Patrick Mochel's sysfs code.
* sysfs is Copyright (c) 2001-3 Patrick Mochel
- * Portions Copyright (c) 2004 Silicon Graphics, Inc.
*
- * 2003-10-10 Written by Simon Derr <simon.derr@bull.net>
+ * 2003-10-10 Written by Simon Derr.
* 2003-10-22 Updates by Stephen Hemminger.
- * 2004 May-July Rework by Paul Jackson <pj@sgi.com>
+ * 2004 May-July Rework by Paul Jackson.
+ * 2006 Rework by Paul Menage to use generic cgroups
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file COPYING in the main directory of the Linux
* distribution for more details.
*/
-#include <linux/config.h>
#include <linux/cpu.h>
#include <linux/cpumask.h>
#include <linux/cpuset.h>
#include <linux/namei.h>
#include <linux/pagemap.h>
#include <linux/proc_fs.h>
+#include <linux/rcupdate.h>
#include <linux/sched.h>
#include <linux/seq_file.h>
+#include <linux/security.h>
#include <linux/slab.h>
-#include <linux/smp_lock.h>
#include <linux/spinlock.h>
#include <linux/stat.h>
#include <linux/string.h>
#include <asm/uaccess.h>
#include <asm/atomic.h>
-#include <asm/semaphore.h>
+#include <linux/mutex.h>
+#include <linux/kfifo.h>
+#include <linux/workqueue.h>
+#include <linux/cgroup.h>
-#define CPUSET_SUPER_MAGIC 0x27e0eb
+/*
+ * Tracks how many cpusets are currently defined in system.
+ * When there is only one cpuset (the root cpuset) we can
+ * short circuit some hooks.
+ */
+int number_of_cpusets __read_mostly;
+
+/* Forward declare cgroup structures */
+struct cgroup_subsys cpuset_subsys;
+struct cpuset;
/* See "Frequency meter" comments, below. */
};
struct cpuset {
+ struct cgroup_subsys_state css;
+
unsigned long flags; /* "unsigned long" so bitops work */
cpumask_t cpus_allowed; /* CPUs allowed to tasks in cpuset */
nodemask_t mems_allowed; /* Memory Nodes allowed to tasks */
- /*
- * Count is atomic so can incr (fork) or decr (exit) without a lock.
- */
- atomic_t count; /* count tasks using this cpuset */
-
- /*
- * We link our 'sibling' struct into our parents 'children'.
- * Our children link their 'sibling' into our 'children'.
- */
- struct list_head sibling; /* my parents children */
- struct list_head children; /* my children */
-
struct cpuset *parent; /* my parent */
- struct dentry *dentry; /* cpuset fs entry */
/*
* Copy of global cpuset_mems_generation as of the most
int mems_generation;
struct fmeter fmeter; /* memory_pressure filter */
+
+ /* partition number for rebuild_sched_domains() */
+ int pn;
+
+ /* used for walking a cpuset heirarchy */
+ struct list_head stack_list;
+};
+
+/* Retrieve the cpuset for a cgroup */
+static inline struct cpuset *cgroup_cs(struct cgroup *cont)
+{
+ return container_of(cgroup_subsys_state(cont, cpuset_subsys_id),
+ struct cpuset, css);
+}
+
+/* Retrieve the cpuset for a task */
+static inline struct cpuset *task_cs(struct task_struct *task)
+{
+ return container_of(task_subsys_state(task, cpuset_subsys_id),
+ struct cpuset, css);
+}
+struct cpuset_hotplug_scanner {
+ struct cgroup_scanner scan;
+ struct cgroup *to;
};
/* bits in struct cpuset flags field */
CS_CPU_EXCLUSIVE,
CS_MEM_EXCLUSIVE,
CS_MEMORY_MIGRATE,
- CS_REMOVED,
- CS_NOTIFY_ON_RELEASE
+ CS_SCHED_LOAD_BALANCE,
+ CS_SPREAD_PAGE,
+ CS_SPREAD_SLAB,
} cpuset_flagbits_t;
/* convenient tests for these bits */
static inline int is_cpu_exclusive(const struct cpuset *cs)
{
- return !!test_bit(CS_CPU_EXCLUSIVE, &cs->flags);
+ return test_bit(CS_CPU_EXCLUSIVE, &cs->flags);
}
static inline int is_mem_exclusive(const struct cpuset *cs)
{
- return !!test_bit(CS_MEM_EXCLUSIVE, &cs->flags);
+ return test_bit(CS_MEM_EXCLUSIVE, &cs->flags);
}
-static inline int is_removed(const struct cpuset *cs)
+static inline int is_sched_load_balance(const struct cpuset *cs)
{
- return !!test_bit(CS_REMOVED, &cs->flags);
+ return test_bit(CS_SCHED_LOAD_BALANCE, &cs->flags);
}
-static inline int notify_on_release(const struct cpuset *cs)
+static inline int is_memory_migrate(const struct cpuset *cs)
{
- return !!test_bit(CS_NOTIFY_ON_RELEASE, &cs->flags);
+ return test_bit(CS_MEMORY_MIGRATE, &cs->flags);
}
-static inline int is_memory_migrate(const struct cpuset *cs)
+static inline int is_spread_page(const struct cpuset *cs)
+{
+ return test_bit(CS_SPREAD_PAGE, &cs->flags);
+}
+
+static inline int is_spread_slab(const struct cpuset *cs)
{
- return !!test_bit(CS_MEMORY_MIGRATE, &cs->flags);
+ return test_bit(CS_SPREAD_SLAB, &cs->flags);
}
/*
- * Increment this atomic integer everytime any cpuset changes its
+ * Increment this integer everytime any cpuset changes its
* mems_allowed value. Users of cpusets can track this generation
* number, and avoid having to lock and reload mems_allowed unless
* the cpuset they're using changes generation.
*
- * A single, global generation is needed because attach_task() could
+ * A single, global generation is needed because cpuset_attach_task() could
* reattach a task to a different cpuset, which must not have its
* generation numbers aliased with those of that tasks previous cpuset.
*
* Generations are needed for mems_allowed because one task cannot
- * modify anothers memory placement. So we must enable every task,
+ * modify another's memory placement. So we must enable every task,
* on every visit to __alloc_pages(), to efficiently check whether
* its current->cpuset->mems_allowed has changed, requiring an update
* of its current->mems_allowed.
+ *
+ * Since writes to cpuset_mems_generation are guarded by the cgroup lock
+ * there is no need to mark it atomic.
*/
-static atomic_t cpuset_mems_generation = ATOMIC_INIT(1);
+static int cpuset_mems_generation;
static struct cpuset top_cpuset = {
.flags = ((1 << CS_CPU_EXCLUSIVE) | (1 << CS_MEM_EXCLUSIVE)),
.cpus_allowed = CPU_MASK_ALL,
.mems_allowed = NODE_MASK_ALL,
- .count = ATOMIC_INIT(0),
- .sibling = LIST_HEAD_INIT(top_cpuset.sibling),
- .children = LIST_HEAD_INIT(top_cpuset.children),
};
-static struct vfsmount *cpuset_mount;
-static struct super_block *cpuset_sb;
-
/*
- * We have two global cpuset semaphores below. They can nest.
- * It is ok to first take manage_sem, then nest callback_sem. We also
- * require taking task_lock() when dereferencing a tasks cpuset pointer.
- * See "The task_lock() exception", at the end of this comment.
- *
- * A task must hold both semaphores to modify cpusets. If a task
- * holds manage_sem, then it blocks others wanting that semaphore,
- * ensuring that it is the only task able to also acquire callback_sem
+ * There are two global mutexes guarding cpuset structures. The first
+ * is the main control groups cgroup_mutex, accessed via
+ * cgroup_lock()/cgroup_unlock(). The second is the cpuset-specific
+ * callback_mutex, below. They can nest. It is ok to first take
+ * cgroup_mutex, then nest callback_mutex. We also require taking
+ * task_lock() when dereferencing a task's cpuset pointer. See "The
+ * task_lock() exception", at the end of this comment.
+ *
+ * A task must hold both mutexes to modify cpusets. If a task
+ * holds cgroup_mutex, then it blocks others wanting that mutex,
+ * ensuring that it is the only task able to also acquire callback_mutex
* and be able to modify cpusets. It can perform various checks on
* the cpuset structure first, knowing nothing will change. It can
- * also allocate memory while just holding manage_sem. While it is
+ * also allocate memory while just holding cgroup_mutex. While it is
* performing these checks, various callback routines can briefly
- * acquire callback_sem to query cpusets. Once it is ready to make
- * the changes, it takes callback_sem, blocking everyone else.
+ * acquire callback_mutex to query cpusets. Once it is ready to make
+ * the changes, it takes callback_mutex, blocking everyone else.
*
* Calls to the kernel memory allocator can not be made while holding
- * callback_sem, as that would risk double tripping on callback_sem
+ * callback_mutex, as that would risk double tripping on callback_mutex
* from one of the callbacks into the cpuset code from within
* __alloc_pages().
*
- * If a task is only holding callback_sem, then it has read-only
+ * If a task is only holding callback_mutex, then it has read-only
* access to cpusets.
*
* The task_struct fields mems_allowed and mems_generation may only
* be accessed in the context of that task, so require no locks.
*
- * Any task can increment and decrement the count field without lock.
- * So in general, code holding manage_sem or callback_sem can't rely
- * on the count field not changing. However, if the count goes to
- * zero, then only attach_task(), which holds both semaphores, can
- * increment it again. Because a count of zero means that no tasks
- * are currently attached, therefore there is no way a task attached
- * to that cpuset can fork (the other way to increment the count).
- * So code holding manage_sem or callback_sem can safely assume that
- * if the count is zero, it will stay zero. Similarly, if a task
- * holds manage_sem or callback_sem on a cpuset with zero count, it
- * knows that the cpuset won't be removed, as cpuset_rmdir() needs
- * both of those semaphores.
- *
- * A possible optimization to improve parallelism would be to make
- * callback_sem a R/W semaphore (rwsem), allowing the callback routines
- * to proceed in parallel, with read access, until the holder of
- * manage_sem needed to take this rwsem for exclusive write access
- * and modify some cpusets.
- *
* The cpuset_common_file_write handler for operations that modify
- * the cpuset hierarchy holds manage_sem across the entire operation,
+ * the cpuset hierarchy holds cgroup_mutex across the entire operation,
* single threading all such cpuset modifications across the system.
*
- * The cpuset_common_file_read() handlers only hold callback_sem across
+ * The cpuset_common_file_read() handlers only hold callback_mutex across
* small pieces of code, such as when reading out possibly multi-word
* cpumasks and nodemasks.
*
- * The fork and exit callbacks cpuset_fork() and cpuset_exit(), don't
- * (usually) take either semaphore. These are the two most performance
- * critical pieces of code here. The exception occurs on cpuset_exit(),
- * when a task in a notify_on_release cpuset exits. Then manage_sem
- * is taken, and if the cpuset count is zero, a usermode call made
- * to /sbin/cpuset_release_agent with the name of the cpuset (path
- * relative to the root of cpuset file system) as the argument.
- *
- * A cpuset can only be deleted if both its 'count' of using tasks
- * is zero, and its list of 'children' cpusets is empty. Since all
- * tasks in the system use _some_ cpuset, and since there is always at
- * least one task in the system (init, pid == 1), therefore, top_cpuset
- * always has either children cpusets and/or using tasks. So we don't
- * need a special hack to ensure that top_cpuset cannot be deleted.
- *
- * The above "Tale of Two Semaphores" would be complete, but for:
- *
- * The task_lock() exception
- *
- * The need for this exception arises from the action of attach_task(),
- * which overwrites one tasks cpuset pointer with another. It does
- * so using both semaphores, however there are several performance
- * critical places that need to reference task->cpuset without the
- * expense of grabbing a system global semaphore. Therefore except as
- * noted below, when dereferencing or, as in attach_task(), modifying
- * a tasks cpuset pointer we use task_lock(), which acts on a spinlock
- * (task->alloc_lock) already in the task_struct routinely used for
- * such matters.
- */
-
-static DECLARE_MUTEX(manage_sem);
-static DECLARE_MUTEX(callback_sem);
-
-/*
- * A couple of forward declarations required, due to cyclic reference loop:
- * cpuset_mkdir -> cpuset_create -> cpuset_populate_dir -> cpuset_add_file
- * -> cpuset_create_file -> cpuset_dir_inode_operations -> cpuset_mkdir.
- */
-
-static int cpuset_mkdir(struct inode *dir, struct dentry *dentry, int mode);
-static int cpuset_rmdir(struct inode *unused_dir, struct dentry *dentry);
-
-static struct backing_dev_info cpuset_backing_dev_info = {
- .ra_pages = 0, /* No readahead */
- .capabilities = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK,
-};
-
-static struct inode *cpuset_new_inode(mode_t mode)
-{
- struct inode *inode = new_inode(cpuset_sb);
-
- if (inode) {
- inode->i_mode = mode;
- inode->i_uid = current->fsuid;
- inode->i_gid = current->fsgid;
- inode->i_blksize = PAGE_CACHE_SIZE;
- inode->i_blocks = 0;
- inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
- inode->i_mapping->backing_dev_info = &cpuset_backing_dev_info;
- }
- return inode;
-}
-
-static void cpuset_diput(struct dentry *dentry, struct inode *inode)
-{
- /* is dentry a directory ? if so, kfree() associated cpuset */
- if (S_ISDIR(inode->i_mode)) {
- struct cpuset *cs = dentry->d_fsdata;
- BUG_ON(!(is_removed(cs)));
- kfree(cs);
- }
- iput(inode);
-}
-
-static struct dentry_operations cpuset_dops = {
- .d_iput = cpuset_diput,
-};
-
-static struct dentry *cpuset_get_dentry(struct dentry *parent, const char *name)
-{
- struct dentry *d = lookup_one_len(name, parent, strlen(name));
- if (!IS_ERR(d))
- d->d_op = &cpuset_dops;
- return d;
-}
-
-static void remove_dir(struct dentry *d)
-{
- struct dentry *parent = dget(d->d_parent);
-
- d_delete(d);
- simple_rmdir(parent->d_inode, d);
- dput(parent);
-}
-
-/*
- * NOTE : the dentry must have been dget()'ed
+ * Accessing a task's cpuset should be done in accordance with the
+ * guidelines for accessing subsystem state in kernel/cgroup.c
*/
-static void cpuset_d_remove_dir(struct dentry *dentry)
-{
- struct list_head *node;
-
- spin_lock(&dcache_lock);
- node = dentry->d_subdirs.next;
- while (node != &dentry->d_subdirs) {
- struct dentry *d = list_entry(node, struct dentry, d_child);
- list_del_init(node);
- if (d->d_inode) {
- d = dget_locked(d);
- spin_unlock(&dcache_lock);
- d_delete(d);
- simple_unlink(dentry->d_inode, d);
- dput(d);
- spin_lock(&dcache_lock);
- }
- node = dentry->d_subdirs.next;
- }
- list_del_init(&dentry->d_child);
- spin_unlock(&dcache_lock);
- remove_dir(dentry);
-}
-
-static struct super_operations cpuset_ops = {
- .statfs = simple_statfs,
- .drop_inode = generic_delete_inode,
-};
-
-static int cpuset_fill_super(struct super_block *sb, void *unused_data,
- int unused_silent)
-{
- struct inode *inode;
- struct dentry *root;
-
- sb->s_blocksize = PAGE_CACHE_SIZE;
- sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
- sb->s_magic = CPUSET_SUPER_MAGIC;
- sb->s_op = &cpuset_ops;
- cpuset_sb = sb;
-
- inode = cpuset_new_inode(S_IFDIR | S_IRUGO | S_IXUGO | S_IWUSR);
- if (inode) {
- inode->i_op = &simple_dir_inode_operations;
- inode->i_fop = &simple_dir_operations;
- /* directories start off with i_nlink == 2 (for "." entry) */
- inode->i_nlink++;
- } else {
- return -ENOMEM;
- }
- root = d_alloc_root(inode);
- if (!root) {
- iput(inode);
- return -ENOMEM;
+static DEFINE_MUTEX(callback_mutex);
+
+/* This is ugly, but preserves the userspace API for existing cpuset
+ * users. If someone tries to mount the "cpuset" filesystem, we
+ * silently switch it to mount "cgroup" instead */
+static int cpuset_get_sb(struct file_system_type *fs_type,
+ int flags, const char *unused_dev_name,
+ void *data, struct vfsmount *mnt)
+{
+ struct file_system_type *cgroup_fs = get_fs_type("cgroup");
+ int ret = -ENODEV;
+ if (cgroup_fs) {
+ char mountopts[] =
+ "cpuset,noprefix,"
+ "release_agent=/sbin/cpuset_release_agent";
+ ret = cgroup_fs->get_sb(cgroup_fs, flags,
+ unused_dev_name, mountopts, mnt);
+ put_filesystem(cgroup_fs);
}
- sb->s_root = root;
- return 0;
-}
-
-static struct super_block *cpuset_get_sb(struct file_system_type *fs_type,
- int flags, const char *unused_dev_name,
- void *data)
-{
- return get_sb_single(fs_type, flags, data, cpuset_fill_super);
+ return ret;
}
static struct file_system_type cpuset_fs_type = {
.name = "cpuset",
.get_sb = cpuset_get_sb,
- .kill_sb = kill_litter_super,
-};
-
-/* struct cftype:
- *
- * The files in the cpuset filesystem mostly have a very simple read/write
- * handling, some common function will take care of it. Nevertheless some cases
- * (read tasks) are special and therefore I define this structure for every
- * kind of file.
- *
- *
- * When reading/writing to a file:
- * - the cpuset to use in file->f_dentry->d_parent->d_fsdata
- * - the 'cftype' of the file is file->f_dentry->d_fsdata
- */
-
-struct cftype {
- char *name;
- int private;
- int (*open) (struct inode *inode, struct file *file);
- ssize_t (*read) (struct file *file, char __user *buf, size_t nbytes,
- loff_t *ppos);
- int (*write) (struct file *file, const char __user *buf, size_t nbytes,
- loff_t *ppos);
- int (*release) (struct inode *inode, struct file *file);
};
-static inline struct cpuset *__d_cs(struct dentry *dentry)
-{
- return dentry->d_fsdata;
-}
-
-static inline struct cftype *__d_cft(struct dentry *dentry)
-{
- return dentry->d_fsdata;
-}
-
-/*
- * Call with manage_sem held. Writes path of cpuset into buf.
- * Returns 0 on success, -errno on error.
- */
-
-static int cpuset_path(const struct cpuset *cs, char *buf, int buflen)
-{
- char *start;
-
- start = buf + buflen;
-
- *--start = '\0';
- for (;;) {
- int len = cs->dentry->d_name.len;
- if ((start -= len) < buf)
- return -ENAMETOOLONG;
- memcpy(start, cs->dentry->d_name.name, len);
- cs = cs->parent;
- if (!cs)
- break;
- if (!cs->parent)
- continue;
- if (--start < buf)
- return -ENAMETOOLONG;
- *start = '/';
- }
- memmove(buf, start, buf + buflen - start);
- return 0;
-}
-
-/*
- * Notify userspace when a cpuset is released, by running
- * /sbin/cpuset_release_agent with the name of the cpuset (path
- * relative to the root of cpuset file system) as the argument.
- *
- * Most likely, this user command will try to rmdir this cpuset.
- *
- * This races with the possibility that some other task will be
- * attached to this cpuset before it is removed, or that some other
- * user task will 'mkdir' a child cpuset of this cpuset. That's ok.
- * The presumed 'rmdir' will fail quietly if this cpuset is no longer
- * unused, and this cpuset will be reprieved from its death sentence,
- * to continue to serve a useful existence. Next time it's released,
- * we will get notified again, if it still has 'notify_on_release' set.
- *
- * The final arg to call_usermodehelper() is 0, which means don't
- * wait. The separate /sbin/cpuset_release_agent task is forked by
- * call_usermodehelper(), then control in this thread returns here,
- * without waiting for the release agent task. We don't bother to
- * wait because the caller of this routine has no use for the exit
- * status of the /sbin/cpuset_release_agent task, so no sense holding
- * our caller up for that.
- *
- * When we had only one cpuset semaphore, we had to call this
- * without holding it, to avoid deadlock when call_usermodehelper()
- * allocated memory. With two locks, we could now call this while
- * holding manage_sem, but we still don't, so as to minimize
- * the time manage_sem is held.
- */
-
-static void cpuset_release_agent(const char *pathbuf)
-{
- char *argv[3], *envp[3];
- int i;
-
- if (!pathbuf)
- return;
-
- i = 0;
- argv[i++] = "/sbin/cpuset_release_agent";
- argv[i++] = (char *)pathbuf;
- argv[i] = NULL;
-
- i = 0;
- /* minimal command environment */
- envp[i++] = "HOME=/";
- envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
- envp[i] = NULL;
-
- call_usermodehelper(argv[0], argv, envp, 0);
- kfree(pathbuf);
-}
-
-/*
- * Either cs->count of using tasks transitioned to zero, or the
- * cs->children list of child cpusets just became empty. If this
- * cs is notify_on_release() and now both the user count is zero and
- * the list of children is empty, prepare cpuset path in a kmalloc'd
- * buffer, to be returned via ppathbuf, so that the caller can invoke
- * cpuset_release_agent() with it later on, once manage_sem is dropped.
- * Call here with manage_sem held.
- *
- * This check_for_release() routine is responsible for kmalloc'ing
- * pathbuf. The above cpuset_release_agent() is responsible for
- * kfree'ing pathbuf. The caller of these routines is responsible
- * for providing a pathbuf pointer, initialized to NULL, then
- * calling check_for_release() with manage_sem held and the address
- * of the pathbuf pointer, then dropping manage_sem, then calling
- * cpuset_release_agent() with pathbuf, as set by check_for_release().
- */
-
-static void check_for_release(struct cpuset *cs, char **ppathbuf)
-{
- if (notify_on_release(cs) && atomic_read(&cs->count) == 0 &&
- list_empty(&cs->children)) {
- char *buf;
-
- buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
- if (!buf)
- return;
- if (cpuset_path(cs, buf, PAGE_SIZE) < 0)
- kfree(buf);
- else
- *ppathbuf = buf;
- }
-}
-
/*
* Return in *pmask the portion of a cpusets's cpus_allowed that
* are online. If none are online, walk up the cpuset hierarchy
* One way or another, we guarantee to return some non-empty subset
* of cpu_online_map.
*
- * Call with callback_sem held.
+ * Call with callback_mutex held.
*/
static void guarantee_online_cpus(const struct cpuset *cs, cpumask_t *pmask)
/*
* Return in *pmask the portion of a cpusets's mems_allowed that
- * are online. If none are online, walk up the cpuset hierarchy
- * until we find one that does have some online mems. If we get
- * all the way to the top and still haven't found any online mems,
- * return node_online_map.
+ * are online, with memory. If none are online with memory, walk
+ * up the cpuset hierarchy until we find one that does have some
+ * online mems. If we get all the way to the top and still haven't
+ * found any online mems, return node_states[N_HIGH_MEMORY].
*
* One way or another, we guarantee to return some non-empty subset
- * of node_online_map.
+ * of node_states[N_HIGH_MEMORY].
*
- * Call with callback_sem held.
+ * Call with callback_mutex held.
*/
static void guarantee_online_mems(const struct cpuset *cs, nodemask_t *pmask)
{
- while (cs && !nodes_intersects(cs->mems_allowed, node_online_map))
+ while (cs && !nodes_intersects(cs->mems_allowed,
+ node_states[N_HIGH_MEMORY]))
cs = cs->parent;
if (cs)
- nodes_and(*pmask, cs->mems_allowed, node_online_map);
+ nodes_and(*pmask, cs->mems_allowed,
+ node_states[N_HIGH_MEMORY]);
else
- *pmask = node_online_map;
- BUG_ON(!nodes_intersects(*pmask, node_online_map));
+ *pmask = node_states[N_HIGH_MEMORY];
+ BUG_ON(!nodes_intersects(*pmask, node_states[N_HIGH_MEMORY]));
}
-/*
- * Refresh current tasks mems_allowed and mems_generation from current
- * tasks cpuset.
+/**
+ * cpuset_update_task_memory_state - update task memory placement
*
- * Call without callback_sem or task_lock() held. May be called with
- * or without manage_sem held. Will acquire task_lock() and might
- * acquire callback_sem during call.
+ * If the current tasks cpusets mems_allowed changed behind our
+ * backs, update current->mems_allowed, mems_generation and task NUMA
+ * mempolicy to the new value.
*
- * The task_lock() is required to dereference current->cpuset safely.
- * Without it, we could pick up the pointer value of current->cpuset
- * in one instruction, and then attach_task could give us a different
- * cpuset, and then the cpuset we had could be removed and freed,
- * and then on our next instruction, we could dereference a no longer
- * valid cpuset pointer to get its mems_generation field.
+ * Task mempolicy is updated by rebinding it relative to the
+ * current->cpuset if a task has its memory placement changed.
+ * Do not call this routine if in_interrupt().
+ *
+ * Call without callback_mutex or task_lock() held. May be
+ * called with or without cgroup_mutex held. Thanks in part to
+ * 'the_top_cpuset_hack', the task's cpuset pointer will never
+ * be NULL. This routine also might acquire callback_mutex during
+ * call.
+ *
+ * Reading current->cpuset->mems_generation doesn't need task_lock
+ * to guard the current->cpuset derefence, because it is guarded
+ * from concurrent freeing of current->cpuset using RCU.
+ *
+ * The rcu_dereference() is technically probably not needed,
+ * as I don't actually mind if I see a new cpuset pointer but
+ * an old value of mems_generation. However this really only
+ * matters on alpha systems using cpusets heavily. If I dropped
+ * that rcu_dereference(), it would save them a memory barrier.
+ * For all other arch's, rcu_dereference is a no-op anyway, and for
+ * alpha systems not using cpusets, another planned optimization,
+ * avoiding the rcu critical section for tasks in the root cpuset
+ * which is statically allocated, so can't vanish, will make this
+ * irrelevant. Better to use RCU as intended, than to engage in
+ * some cute trick to save a memory barrier that is impossible to
+ * test, for alpha systems using cpusets heavily, which might not
+ * even exist.
*
* This routine is needed to update the per-task mems_allowed data,
* within the tasks context, when it is trying to allocate memory
* task has been modifying its cpuset.
*/
-static void refresh_mems(void)
+void cpuset_update_task_memory_state(void)
{
int my_cpusets_mem_gen;
+ struct task_struct *tsk = current;
+ struct cpuset *cs;
- task_lock(current);
- my_cpusets_mem_gen = current->cpuset->mems_generation;
- task_unlock(current);
+ if (task_cs(tsk) == &top_cpuset) {
+ /* Don't need rcu for top_cpuset. It's never freed. */
+ my_cpusets_mem_gen = top_cpuset.mems_generation;
+ } else {
+ rcu_read_lock();
+ my_cpusets_mem_gen = task_cs(current)->mems_generation;
+ rcu_read_unlock();
+ }
- if (current->cpuset_mems_generation != my_cpusets_mem_gen) {
- struct cpuset *cs;
- nodemask_t oldmem = current->mems_allowed;
- int migrate;
-
- down(&callback_sem);
- task_lock(current);
- cs = current->cpuset;
- migrate = is_memory_migrate(cs);
- guarantee_online_mems(cs, ¤t->mems_allowed);
- current->cpuset_mems_generation = cs->mems_generation;
- task_unlock(current);
- up(&callback_sem);
- if (!nodes_equal(oldmem, current->mems_allowed)) {
- numa_policy_rebind(&oldmem, ¤t->mems_allowed);
- if (migrate) {
- do_migrate_pages(current->mm, &oldmem,
- ¤t->mems_allowed,
- MPOL_MF_MOVE_ALL);
- }
- }
+ if (my_cpusets_mem_gen != tsk->cpuset_mems_generation) {
+ mutex_lock(&callback_mutex);
+ task_lock(tsk);
+ cs = task_cs(tsk); /* Maybe changed when task not locked */
+ guarantee_online_mems(cs, &tsk->mems_allowed);
+ tsk->cpuset_mems_generation = cs->mems_generation;
+ if (is_spread_page(cs))
+ tsk->flags |= PF_SPREAD_PAGE;
+ else
+ tsk->flags &= ~PF_SPREAD_PAGE;
+ if (is_spread_slab(cs))
+ tsk->flags |= PF_SPREAD_SLAB;
+ else
+ tsk->flags &= ~PF_SPREAD_SLAB;
+ task_unlock(tsk);
+ mutex_unlock(&callback_mutex);
+ mpol_rebind_task(tsk, &tsk->mems_allowed);
}
}
*
* One cpuset is a subset of another if all its allowed CPUs and
* Memory Nodes are a subset of the other, and its exclusive flags
- * are only set if the other's are set. Call holding manage_sem.
+ * are only set if the other's are set. Call holding cgroup_mutex.
*/
static int is_cpuset_subset(const struct cpuset *p, const struct cpuset *q)
* If we replaced the flag and mask values of the current cpuset
* (cur) with those values in the trial cpuset (trial), would
* our various subset and exclusive rules still be valid? Presumes
- * manage_sem held.
+ * cgroup_mutex held.
*
* 'cur' is the address of an actual, in-use cpuset. Operations
* such as list traversal that depend on the actual address of the
static int validate_change(const struct cpuset *cur, const struct cpuset *trial)
{
+ struct cgroup *cont;
struct cpuset *c, *par;
/* Each of our child cpusets must be a subset of us */
- list_for_each_entry(c, &cur->children, sibling) {
- if (!is_cpuset_subset(c, trial))
+ list_for_each_entry(cont, &cur->css.cgroup->children, sibling) {
+ if (!is_cpuset_subset(cgroup_cs(cont), trial))
return -EBUSY;
}
/* Remaining checks don't apply to root cpuset */
- if ((par = cur->parent) == NULL)
+ if (cur == &top_cpuset)
return 0;
+ par = cur->parent;
+
/* We must be a subset of our parent cpuset */
if (!is_cpuset_subset(trial, par))
return -EACCES;
- /* If either I or some sibling (!= me) is exclusive, we can't overlap */
- list_for_each_entry(c, &par->children, sibling) {
+ /*
+ * If either I or some sibling (!= me) is exclusive, we can't
+ * overlap
+ */
+ list_for_each_entry(cont, &par->css.cgroup->children, sibling) {
+ c = cgroup_cs(cont);
if ((is_cpu_exclusive(trial) || is_cpu_exclusive(c)) &&
c != cur &&
cpus_intersects(trial->cpus_allowed, c->cpus_allowed))
return -EINVAL;
}
+ /* Cpusets with tasks can't have empty cpus_allowed or mems_allowed */
+ if (cgroup_task_count(cur->css.cgroup)) {
+ if (cpus_empty(trial->cpus_allowed) ||
+ nodes_empty(trial->mems_allowed)) {
+ return -ENOSPC;
+ }
+ }
+
return 0;
}
/*
- * For a given cpuset cur, partition the system as follows
- * a. All cpus in the parent cpuset's cpus_allowed that are not part of any
- * exclusive child cpusets
- * b. All cpus in the current cpuset's cpus_allowed that are not part of any
- * exclusive child cpusets
- * Build these two partitions by calling partition_sched_domains
- *
- * Call with manage_sem held. May nest a call to the
- * lock_cpu_hotplug()/unlock_cpu_hotplug() pair.
+ * Helper routine for rebuild_sched_domains().
+ * Do cpusets a, b have overlapping cpus_allowed masks?
*/
-static void update_cpu_domains(struct cpuset *cur)
+static int cpusets_overlap(struct cpuset *a, struct cpuset *b)
{
- struct cpuset *c, *par = cur->parent;
- cpumask_t pspan, cspan;
+ return cpus_intersects(a->cpus_allowed, b->cpus_allowed);
+}
- if (par == NULL || cpus_empty(cur->cpus_allowed))
- return;
+/*
+ * rebuild_sched_domains()
+ *
+ * If the flag 'sched_load_balance' of any cpuset with non-empty
+ * 'cpus' changes, or if the 'cpus' allowed changes in any cpuset
+ * which has that flag enabled, or if any cpuset with a non-empty
+ * 'cpus' is removed, then call this routine to rebuild the
+ * scheduler's dynamic sched domains.
+ *
+ * This routine builds a partial partition of the systems CPUs
+ * (the set of non-overlappping cpumask_t's in the array 'part'
+ * below), and passes that partial partition to the kernel/sched.c
+ * partition_sched_domains() routine, which will rebuild the
+ * schedulers load balancing domains (sched domains) as specified
+ * by that partial partition. A 'partial partition' is a set of
+ * non-overlapping subsets whose union is a subset of that set.
+ *
+ * See "What is sched_load_balance" in Documentation/cpusets.txt
+ * for a background explanation of this.
+ *
+ * Does not return errors, on the theory that the callers of this
+ * routine would rather not worry about failures to rebuild sched
+ * domains when operating in the severe memory shortage situations
+ * that could cause allocation failures below.
+ *
+ * Call with cgroup_mutex held. May take callback_mutex during
+ * call due to the kfifo_alloc() and kmalloc() calls. May nest
+ * a call to the get_online_cpus()/put_online_cpus() pair.
+ * Must not be called holding callback_mutex, because we must not
+ * call get_online_cpus() while holding callback_mutex. Elsewhere
+ * the kernel nests callback_mutex inside get_online_cpus() calls.
+ * So the reverse nesting would risk an ABBA deadlock.
+ *
+ * The three key local variables below are:
+ * q - a kfifo queue of cpuset pointers, used to implement a
+ * top-down scan of all cpusets. This scan loads a pointer
+ * to each cpuset marked is_sched_load_balance into the
+ * array 'csa'. For our purposes, rebuilding the schedulers
+ * sched domains, we can ignore !is_sched_load_balance cpusets.
+ * csa - (for CpuSet Array) Array of pointers to all the cpusets
+ * that need to be load balanced, for convenient iterative
+ * access by the subsequent code that finds the best partition,
+ * i.e the set of domains (subsets) of CPUs such that the
+ * cpus_allowed of every cpuset marked is_sched_load_balance
+ * is a subset of one of these domains, while there are as
+ * many such domains as possible, each as small as possible.
+ * doms - Conversion of 'csa' to an array of cpumasks, for passing to
+ * the kernel/sched.c routine partition_sched_domains() in a
+ * convenient format, that can be easily compared to the prior
+ * value to determine what partition elements (sched domains)
+ * were changed (added or removed.)
+ *
+ * Finding the best partition (set of domains):
+ * The triple nested loops below over i, j, k scan over the
+ * load balanced cpusets (using the array of cpuset pointers in
+ * csa[]) looking for pairs of cpusets that have overlapping
+ * cpus_allowed, but which don't have the same 'pn' partition
+ * number and gives them in the same partition number. It keeps
+ * looping on the 'restart' label until it can no longer find
+ * any such pairs.
+ *
+ * The union of the cpus_allowed masks from the set of
+ * all cpusets having the same 'pn' value then form the one
+ * element of the partition (one sched domain) to be passed to
+ * partition_sched_domains().
+ */
- /*
- * Get all cpus from parent's cpus_allowed not part of exclusive
- * children
- */
- pspan = par->cpus_allowed;
- list_for_each_entry(c, &par->children, sibling) {
- if (is_cpu_exclusive(c))
- cpus_andnot(pspan, pspan, c->cpus_allowed);
+static void rebuild_sched_domains(void)
+{
+ struct kfifo *q; /* queue of cpusets to be scanned */
+ struct cpuset *cp; /* scans q */
+ struct cpuset **csa; /* array of all cpuset ptrs */
+ int csn; /* how many cpuset ptrs in csa so far */
+ int i, j, k; /* indices for partition finding loops */
+ cpumask_t *doms; /* resulting partition; i.e. sched domains */
+ int ndoms; /* number of sched domains in result */
+ int nslot; /* next empty doms[] cpumask_t slot */
+
+ q = NULL;
+ csa = NULL;
+ doms = NULL;
+
+ /* Special case for the 99% of systems with one, full, sched domain */
+ if (is_sched_load_balance(&top_cpuset)) {
+ ndoms = 1;
+ doms = kmalloc(sizeof(cpumask_t), GFP_KERNEL);
+ if (!doms)
+ goto rebuild;
+ *doms = top_cpuset.cpus_allowed;
+ goto rebuild;
}
- if (is_removed(cur) || !is_cpu_exclusive(cur)) {
- cpus_or(pspan, pspan, cur->cpus_allowed);
- if (cpus_equal(pspan, cur->cpus_allowed))
- return;
- cspan = CPU_MASK_NONE;
+
+ q = kfifo_alloc(number_of_cpusets * sizeof(cp), GFP_KERNEL, NULL);
+ if (IS_ERR(q))
+ goto done;
+ csa = kmalloc(number_of_cpusets * sizeof(cp), GFP_KERNEL);
+ if (!csa)
+ goto done;
+ csn = 0;
+
+ cp = &top_cpuset;
+ __kfifo_put(q, (void *)&cp, sizeof(cp));
+ while (__kfifo_get(q, (void *)&cp, sizeof(cp))) {
+ struct cgroup *cont;
+ struct cpuset *child; /* scans child cpusets of cp */
+ if (is_sched_load_balance(cp))
+ csa[csn++] = cp;
+ list_for_each_entry(cont, &cp->css.cgroup->children, sibling) {
+ child = cgroup_cs(cont);
+ __kfifo_put(q, (void *)&child, sizeof(cp));
+ }
+ }
+
+ for (i = 0; i < csn; i++)
+ csa[i]->pn = i;
+ ndoms = csn;
+
+restart:
+ /* Find the best partition (set of sched domains) */
+ for (i = 0; i < csn; i++) {
+ struct cpuset *a = csa[i];
+ int apn = a->pn;
+
+ for (j = 0; j < csn; j++) {
+ struct cpuset *b = csa[j];
+ int bpn = b->pn;
+
+ if (apn != bpn && cpusets_overlap(a, b)) {
+ for (k = 0; k < csn; k++) {
+ struct cpuset *c = csa[k];
+
+ if (c->pn == bpn)
+ c->pn = apn;
+ }
+ ndoms--; /* one less element */
+ goto restart;
+ }
+ }
+ }
+
+ /* Convert <csn, csa> to <ndoms, doms> */
+ doms = kmalloc(ndoms * sizeof(cpumask_t), GFP_KERNEL);
+ if (!doms)
+ goto rebuild;
+
+ for (nslot = 0, i = 0; i < csn; i++) {
+ struct cpuset *a = csa[i];
+ int apn = a->pn;
+
+ if (apn >= 0) {
+ cpumask_t *dp = doms + nslot;
+
+ if (nslot == ndoms) {
+ static int warnings = 10;
+ if (warnings) {
+ printk(KERN_WARNING
+ "rebuild_sched_domains confused:"
+ " nslot %d, ndoms %d, csn %d, i %d,"
+ " apn %d\n",
+ nslot, ndoms, csn, i, apn);
+ warnings--;
+ }
+ continue;
+ }
+
+ cpus_clear(*dp);
+ for (j = i; j < csn; j++) {
+ struct cpuset *b = csa[j];
+
+ if (apn == b->pn) {
+ cpus_or(*dp, *dp, b->cpus_allowed);
+ b->pn = -1;
+ }
+ }
+ nslot++;
+ }
+ }
+ BUG_ON(nslot != ndoms);
+
+rebuild:
+ /* Have scheduler rebuild sched domains */
+ get_online_cpus();
+ partition_sched_domains(ndoms, doms);
+ put_online_cpus();
+
+done:
+ if (q && !IS_ERR(q))
+ kfifo_free(q);
+ kfree(csa);
+ /* Don't kfree(doms) -- partition_sched_domains() does that. */
+}
+
+static inline int started_after_time(struct task_struct *t1,
+ struct timespec *time,
+ struct task_struct *t2)
+{
+ int start_diff = timespec_compare(&t1->start_time, time);
+ if (start_diff > 0) {
+ return 1;
+ } else if (start_diff < 0) {
+ return 0;
} else {
- if (cpus_empty(pspan))
- return;
- cspan = cur->cpus_allowed;
/*
- * Get all cpus from current cpuset's cpus_allowed not part
- * of exclusive children
+ * Arbitrarily, if two processes started at the same
+ * time, we'll say that the lower pointer value
+ * started first. Note that t2 may have exited by now
+ * so this may not be a valid pointer any longer, but
+ * that's fine - it still serves to distinguish
+ * between two tasks started (effectively)
+ * simultaneously.
*/
- list_for_each_entry(c, &cur->children, sibling) {
- if (is_cpu_exclusive(c))
- cpus_andnot(cspan, cspan, c->cpus_allowed);
- }
+ return t1 > t2;
}
+}
- lock_cpu_hotplug();
- partition_sched_domains(&pspan, &cspan);
- unlock_cpu_hotplug();
+static inline int started_after(void *p1, void *p2)
+{
+ struct task_struct *t1 = p1;
+ struct task_struct *t2 = p2;
+ return started_after_time(t1, &t2->start_time, t2);
}
-/*
- * Call with manage_sem held. May take callback_sem during call.
+/**
+ * cpuset_test_cpumask - test a task's cpus_allowed versus its cpuset's
+ * @tsk: task to test
+ * @scan: struct cgroup_scanner contained in its struct cpuset_hotplug_scanner
+ *
+ * Call with cgroup_mutex held. May take callback_mutex during call.
+ * Called for each task in a cgroup by cgroup_scan_tasks().
+ * Return nonzero if this tasks's cpus_allowed mask should be changed (in other
+ * words, if its mask is not equal to its cpuset's mask).
+ */
+int cpuset_test_cpumask(struct task_struct *tsk, struct cgroup_scanner *scan)
+{
+ return !cpus_equal(tsk->cpus_allowed,
+ (cgroup_cs(scan->cg))->cpus_allowed);
+}
+
+/**
+ * cpuset_change_cpumask - make a task's cpus_allowed the same as its cpuset's
+ * @tsk: task to test
+ * @scan: struct cgroup_scanner containing the cgroup of the task
+ *
+ * Called by cgroup_scan_tasks() for each task in a cgroup whose
+ * cpus_allowed mask needs to be changed.
+ *
+ * We don't need to re-check for the cgroup/cpuset membership, since we're
+ * holding cgroup_lock() at this point.
*/
+void cpuset_change_cpumask(struct task_struct *tsk, struct cgroup_scanner *scan)
+{
+ set_cpus_allowed(tsk, (cgroup_cs(scan->cg))->cpus_allowed);
+}
+/**
+ * update_cpumask - update the cpus_allowed mask of a cpuset and all tasks in it
+ * @cs: the cpuset to consider
+ * @buf: buffer of cpu numbers written to this cpuset
+ */
static int update_cpumask(struct cpuset *cs, char *buf)
{
struct cpuset trialcs;
- int retval, cpus_unchanged;
+ struct cgroup_scanner scan;
+ struct ptr_heap heap;
+ int retval;
+ int is_load_balanced;
+
+ /* top_cpuset.cpus_allowed tracks cpu_online_map; it's read-only */
+ if (cs == &top_cpuset)
+ return -EACCES;
trialcs = *cs;
- retval = cpulist_parse(buf, trialcs.cpus_allowed);
- if (retval < 0)
- return retval;
+
+ /*
+ * An empty cpus_allowed is ok only if the cpuset has no tasks.
+ * Since cpulist_parse() fails on an empty mask, we special case
+ * that parsing. The validate_change() call ensures that cpusets
+ * with tasks have cpus.
+ */
+ buf = strstrip(buf);
+ if (!*buf) {
+ cpus_clear(trialcs.cpus_allowed);
+ } else {
+ retval = cpulist_parse(buf, trialcs.cpus_allowed);
+ if (retval < 0)
+ return retval;
+ }
cpus_and(trialcs.cpus_allowed, trialcs.cpus_allowed, cpu_online_map);
- if (cpus_empty(trialcs.cpus_allowed))
- return -ENOSPC;
retval = validate_change(cs, &trialcs);
if (retval < 0)
return retval;
- cpus_unchanged = cpus_equal(cs->cpus_allowed, trialcs.cpus_allowed);
- down(&callback_sem);
+
+ /* Nothing to do if the cpus didn't change */
+ if (cpus_equal(cs->cpus_allowed, trialcs.cpus_allowed))
+ return 0;
+
+ retval = heap_init(&heap, PAGE_SIZE, GFP_KERNEL, &started_after);
+ if (retval)
+ return retval;
+
+ is_load_balanced = is_sched_load_balance(&trialcs);
+
+ mutex_lock(&callback_mutex);
cs->cpus_allowed = trialcs.cpus_allowed;
- up(&callback_sem);
- if (is_cpu_exclusive(cs) && !cpus_unchanged)
- update_cpu_domains(cs);
+ mutex_unlock(&callback_mutex);
+
+ /*
+ * Scan tasks in the cpuset, and update the cpumasks of any
+ * that need an update.
+ */
+ scan.cg = cs->css.cgroup;
+ scan.test_task = cpuset_test_cpumask;
+ scan.process_task = cpuset_change_cpumask;
+ scan.heap = &heap;
+ cgroup_scan_tasks(&scan);
+ heap_free(&heap);
+
+ if (is_load_balanced)
+ rebuild_sched_domains();
return 0;
}
/*
- * Call with manage_sem held. May take callback_sem during call.
+ * cpuset_migrate_mm
+ *
+ * Migrate memory region from one set of nodes to another.
+ *
+ * Temporarilly set tasks mems_allowed to target nodes of migration,
+ * so that the migration code can allocate pages on these nodes.
+ *
+ * Call holding cgroup_mutex, so current's cpuset won't change
+ * during this call, as manage_mutex holds off any cpuset_attach()
+ * calls. Therefore we don't need to take task_lock around the
+ * call to guarantee_online_mems(), as we know no one is changing
+ * our task's cpuset.
+ *
+ * Hold callback_mutex around the two modifications of our tasks
+ * mems_allowed to synchronize with cpuset_mems_allowed().
+ *
+ * While the mm_struct we are migrating is typically from some
+ * other task, the task_struct mems_allowed that we are hacking
+ * is for our current task, which must allocate new pages for that
+ * migrating memory region.
+ *
+ * We call cpuset_update_task_memory_state() before hacking
+ * our tasks mems_allowed, so that we are assured of being in
+ * sync with our tasks cpuset, and in particular, callbacks to
+ * cpuset_update_task_memory_state() from nested page allocations
+ * won't see any mismatch of our cpuset and task mems_generation
+ * values, so won't overwrite our hacked tasks mems_allowed
+ * nodemask.
*/
+static void cpuset_migrate_mm(struct mm_struct *mm, const nodemask_t *from,
+ const nodemask_t *to)
+{
+ struct task_struct *tsk = current;
+
+ cpuset_update_task_memory_state();
+
+ mutex_lock(&callback_mutex);
+ tsk->mems_allowed = *to;
+ mutex_unlock(&callback_mutex);
+
+ do_migrate_pages(mm, from, to, MPOL_MF_MOVE_ALL);
+
+ mutex_lock(&callback_mutex);
+ guarantee_online_mems(task_cs(tsk),&tsk->mems_allowed);
+ mutex_unlock(&callback_mutex);
+}
+
+/*
+ * Handle user request to change the 'mems' memory placement
+ * of a cpuset. Needs to validate the request, update the
+ * cpusets mems_allowed and mems_generation, and for each
+ * task in the cpuset, rebind any vma mempolicies and if
+ * the cpuset is marked 'memory_migrate', migrate the tasks
+ * pages to the new memory.
+ *
+ * Call with cgroup_mutex held. May take callback_mutex during call.
+ * Will take tasklist_lock, scan tasklist for tasks in cpuset cs,
+ * lock each such tasks mm->mmap_sem, scan its vma's and rebind
+ * their mempolicies to the cpusets new mems_allowed.
+ */
+
+static void *cpuset_being_rebound;
+
static int update_nodemask(struct cpuset *cs, char *buf)
{
struct cpuset trialcs;
+ nodemask_t oldmem;
+ struct task_struct *p;
+ struct mm_struct **mmarray;
+ int i, n, ntasks;
+ int migrate;
+ int fudge;
int retval;
+ struct cgroup_iter it;
+
+ /*
+ * top_cpuset.mems_allowed tracks node_stats[N_HIGH_MEMORY];
+ * it's read-only
+ */
+ if (cs == &top_cpuset)
+ return -EACCES;
trialcs = *cs;
- retval = nodelist_parse(buf, trialcs.mems_allowed);
- if (retval < 0)
- return retval;
- nodes_and(trialcs.mems_allowed, trialcs.mems_allowed, node_online_map);
- if (nodes_empty(trialcs.mems_allowed))
- return -ENOSPC;
+
+ /*
+ * An empty mems_allowed is ok iff there are no tasks in the cpuset.
+ * Since nodelist_parse() fails on an empty mask, we special case
+ * that parsing. The validate_change() call ensures that cpusets
+ * with tasks have memory.
+ */
+ buf = strstrip(buf);
+ if (!*buf) {
+ nodes_clear(trialcs.mems_allowed);
+ } else {
+ retval = nodelist_parse(buf, trialcs.mems_allowed);
+ if (retval < 0)
+ goto done;
+ }
+ nodes_and(trialcs.mems_allowed, trialcs.mems_allowed,
+ node_states[N_HIGH_MEMORY]);
+ oldmem = cs->mems_allowed;
+ if (nodes_equal(oldmem, trialcs.mems_allowed)) {
+ retval = 0; /* Too easy - nothing to do */
+ goto done;
+ }
retval = validate_change(cs, &trialcs);
- if (retval == 0) {
- down(&callback_sem);
- cs->mems_allowed = trialcs.mems_allowed;
- atomic_inc(&cpuset_mems_generation);
- cs->mems_generation = atomic_read(&cpuset_mems_generation);
- up(&callback_sem);
+ if (retval < 0)
+ goto done;
+
+ mutex_lock(&callback_mutex);
+ cs->mems_allowed = trialcs.mems_allowed;
+ cs->mems_generation = cpuset_mems_generation++;
+ mutex_unlock(&callback_mutex);
+
+ cpuset_being_rebound = cs; /* causes mpol_copy() rebind */
+
+ fudge = 10; /* spare mmarray[] slots */
+ fudge += cpus_weight(cs->cpus_allowed); /* imagine one fork-bomb/cpu */
+ retval = -ENOMEM;
+
+ /*
+ * Allocate mmarray[] to hold mm reference for each task
+ * in cpuset cs. Can't kmalloc GFP_KERNEL while holding
+ * tasklist_lock. We could use GFP_ATOMIC, but with a
+ * few more lines of code, we can retry until we get a big
+ * enough mmarray[] w/o using GFP_ATOMIC.
+ */
+ while (1) {
+ ntasks = cgroup_task_count(cs->css.cgroup); /* guess */
+ ntasks += fudge;
+ mmarray = kmalloc(ntasks * sizeof(*mmarray), GFP_KERNEL);
+ if (!mmarray)
+ goto done;
+ read_lock(&tasklist_lock); /* block fork */
+ if (cgroup_task_count(cs->css.cgroup) <= ntasks)
+ break; /* got enough */
+ read_unlock(&tasklist_lock); /* try again */
+ kfree(mmarray);
+ }
+
+ n = 0;
+
+ /* Load up mmarray[] with mm reference for each task in cpuset. */
+ cgroup_iter_start(cs->css.cgroup, &it);
+ while ((p = cgroup_iter_next(cs->css.cgroup, &it))) {
+ struct mm_struct *mm;
+
+ if (n >= ntasks) {
+ printk(KERN_WARNING
+ "Cpuset mempolicy rebind incomplete.\n");
+ break;
+ }
+ mm = get_task_mm(p);
+ if (!mm)
+ continue;
+ mmarray[n++] = mm;
}
+ cgroup_iter_end(cs->css.cgroup, &it);
+ read_unlock(&tasklist_lock);
+
+ /*
+ * Now that we've dropped the tasklist spinlock, we can
+ * rebind the vma mempolicies of each mm in mmarray[] to their
+ * new cpuset, and release that mm. The mpol_rebind_mm()
+ * call takes mmap_sem, which we couldn't take while holding
+ * tasklist_lock. Forks can happen again now - the mpol_copy()
+ * cpuset_being_rebound check will catch such forks, and rebind
+ * their vma mempolicies too. Because we still hold the global
+ * cgroup_mutex, we know that no other rebind effort will
+ * be contending for the global variable cpuset_being_rebound.
+ * It's ok if we rebind the same mm twice; mpol_rebind_mm()
+ * is idempotent. Also migrate pages in each mm to new nodes.
+ */
+ migrate = is_memory_migrate(cs);
+ for (i = 0; i < n; i++) {
+ struct mm_struct *mm = mmarray[i];
+
+ mpol_rebind_mm(mm, &cs->mems_allowed);
+ if (migrate)
+ cpuset_migrate_mm(mm, &oldmem, &cs->mems_allowed);
+ mmput(mm);
+ }
+
+ /* We're done rebinding vmas to this cpuset's new mems_allowed. */
+ kfree(mmarray);
+ cpuset_being_rebound = NULL;
+ retval = 0;
+done:
return retval;
}
+int current_cpuset_is_being_rebound(void)
+{
+ return task_cs(current) == cpuset_being_rebound;
+}
+
/*
- * Call with manage_sem held.
+ * Call with cgroup_mutex held.
*/
static int update_memory_pressure_enabled(struct cpuset *cs, char *buf)
/*
* update_flag - read a 0 or a 1 in a file and update associated flag
* bit: the bit to update (CS_CPU_EXCLUSIVE, CS_MEM_EXCLUSIVE,
- * CS_NOTIFY_ON_RELEASE, CS_MEMORY_MIGRATE)
+ * CS_SCHED_LOAD_BALANCE,
+ * CS_NOTIFY_ON_RELEASE, CS_MEMORY_MIGRATE,
+ * CS_SPREAD_PAGE, CS_SPREAD_SLAB)
* cs: the cpuset to update
* buf: the buffer where we read the 0 or 1
*
- * Call with manage_sem held.
+ * Call with cgroup_mutex held.
*/
static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs, char *buf)
{
int turning_on;
struct cpuset trialcs;
- int err, cpu_exclusive_changed;
+ int err;
+ int cpus_nonempty, balance_flag_changed;
turning_on = (simple_strtoul(buf, NULL, 10) != 0);
err = validate_change(cs, &trialcs);
if (err < 0)
return err;
- cpu_exclusive_changed =
- (is_cpu_exclusive(cs) != is_cpu_exclusive(&trialcs));
- down(&callback_sem);
- if (turning_on)
- set_bit(bit, &cs->flags);
- else
- clear_bit(bit, &cs->flags);
- up(&callback_sem);
- if (cpu_exclusive_changed)
- update_cpu_domains(cs);
+ cpus_nonempty = !cpus_empty(trialcs.cpus_allowed);
+ balance_flag_changed = (is_sched_load_balance(cs) !=
+ is_sched_load_balance(&trialcs));
+
+ mutex_lock(&callback_mutex);
+ cs->flags = trialcs.flags;
+ mutex_unlock(&callback_mutex);
+
+ if (cpus_nonempty && balance_flag_changed)
+ rebuild_sched_domains();
+
return 0;
}
/*
- * Frequency meter - How fast is some event occuring?
+ * Frequency meter - How fast is some event occurring?
*
* These routines manage a digitally filtered, constant time based,
* event frequency meter. There are four routines:
return val;
}
-/*
- * Attack task specified by pid in 'pidbuf' to cpuset 'cs', possibly
- * writing the path of the old cpuset in 'ppathbuf' if it needs to be
- * notified on release.
- *
- * Call holding manage_sem. May take callback_sem and task_lock of
- * the task 'pid' during call.
- */
-
-static int attach_task(struct cpuset *cs, char *pidbuf, char **ppathbuf)
+/* Called by cgroups to determine if a cpuset is usable; cgroup_mutex held */
+static int cpuset_can_attach(struct cgroup_subsys *ss,
+ struct cgroup *cont, struct task_struct *tsk)
{
- pid_t pid;
- struct task_struct *tsk;
- struct cpuset *oldcs;
- cpumask_t cpus;
- nodemask_t from, to;
+ struct cpuset *cs = cgroup_cs(cont);
- if (sscanf(pidbuf, "%d", &pid) != 1)
- return -EIO;
if (cpus_empty(cs->cpus_allowed) || nodes_empty(cs->mems_allowed))
return -ENOSPC;
- if (pid) {
- read_lock(&tasklist_lock);
-
- tsk = find_task_by_pid(pid);
- if (!tsk || tsk->flags & PF_EXITING) {
- read_unlock(&tasklist_lock);
- return -ESRCH;
- }
-
- get_task_struct(tsk);
- read_unlock(&tasklist_lock);
-
- if ((current->euid) && (current->euid != tsk->uid)
- && (current->euid != tsk->suid)) {
- put_task_struct(tsk);
- return -EACCES;
- }
- } else {
- tsk = current;
- get_task_struct(tsk);
- }
-
- down(&callback_sem);
+ return security_task_setscheduler(tsk, 0, NULL);
+}
- task_lock(tsk);
- oldcs = tsk->cpuset;
- if (!oldcs) {
- task_unlock(tsk);
- up(&callback_sem);
- put_task_struct(tsk);
- return -ESRCH;
- }
- atomic_inc(&cs->count);
- tsk->cpuset = cs;
- task_unlock(tsk);
+static void cpuset_attach(struct cgroup_subsys *ss,
+ struct cgroup *cont, struct cgroup *oldcont,
+ struct task_struct *tsk)
+{
+ cpumask_t cpus;
+ nodemask_t from, to;
+ struct mm_struct *mm;
+ struct cpuset *cs = cgroup_cs(cont);
+ struct cpuset *oldcs = cgroup_cs(oldcont);
+ mutex_lock(&callback_mutex);
guarantee_online_cpus(cs, &cpus);
set_cpus_allowed(tsk, cpus);
+ mutex_unlock(&callback_mutex);
from = oldcs->mems_allowed;
to = cs->mems_allowed;
+ mm = get_task_mm(tsk);
+ if (mm) {
+ mpol_rebind_mm(mm, &to);
+ if (is_memory_migrate(cs))
+ cpuset_migrate_mm(mm, &from, &to);
+ mmput(mm);
+ }
- up(&callback_sem);
- if (is_memory_migrate(cs))
- do_migrate_pages(tsk->mm, &from, &to, MPOL_MF_MOVE_ALL);
- put_task_struct(tsk);
- if (atomic_dec_and_test(&oldcs->count))
- check_for_release(oldcs, ppathbuf);
- return 0;
}
/* The various types of files and directories in a cpuset file system */
typedef enum {
- FILE_ROOT,
- FILE_DIR,
FILE_MEMORY_MIGRATE,
FILE_CPULIST,
FILE_MEMLIST,
FILE_CPU_EXCLUSIVE,
FILE_MEM_EXCLUSIVE,
- FILE_NOTIFY_ON_RELEASE,
+ FILE_SCHED_LOAD_BALANCE,
FILE_MEMORY_PRESSURE_ENABLED,
FILE_MEMORY_PRESSURE,
- FILE_TASKLIST,
+ FILE_SPREAD_PAGE,
+ FILE_SPREAD_SLAB,
} cpuset_filetype_t;
-static ssize_t cpuset_common_file_write(struct file *file, const char __user *userbuf,
+static ssize_t cpuset_common_file_write(struct cgroup *cont,
+ struct cftype *cft,
+ struct file *file,
+ const char __user *userbuf,
size_t nbytes, loff_t *unused_ppos)
{
- struct cpuset *cs = __d_cs(file->f_dentry->d_parent);
- struct cftype *cft = __d_cft(file->f_dentry);
+ struct cpuset *cs = cgroup_cs(cont);
cpuset_filetype_t type = cft->private;
char *buffer;
- char *pathbuf = NULL;
int retval = 0;
/* Crude upper limit on largest legitimate cpulist user might write. */
- if (nbytes > 100 + 6 * NR_CPUS)
+ if (nbytes > 100U + 6 * max(NR_CPUS, MAX_NUMNODES))
return -E2BIG;
/* +1 for nul-terminator */
}
buffer[nbytes] = 0; /* nul-terminate */
- down(&manage_sem);
+ cgroup_lock();
- if (is_removed(cs)) {
+ if (cgroup_is_removed(cont)) {
retval = -ENODEV;
goto out2;
}
case FILE_MEM_EXCLUSIVE:
retval = update_flag(CS_MEM_EXCLUSIVE, cs, buffer);
break;
- case FILE_NOTIFY_ON_RELEASE:
- retval = update_flag(CS_NOTIFY_ON_RELEASE, cs, buffer);
+ case FILE_SCHED_LOAD_BALANCE:
+ retval = update_flag(CS_SCHED_LOAD_BALANCE, cs, buffer);
break;
case FILE_MEMORY_MIGRATE:
retval = update_flag(CS_MEMORY_MIGRATE, cs, buffer);
case FILE_MEMORY_PRESSURE:
retval = -EACCES;
break;
- case FILE_TASKLIST:
- retval = attach_task(cs, buffer, &pathbuf);
+ case FILE_SPREAD_PAGE:
+ retval = update_flag(CS_SPREAD_PAGE, cs, buffer);
+ cs->mems_generation = cpuset_mems_generation++;
+ break;
+ case FILE_SPREAD_SLAB:
+ retval = update_flag(CS_SPREAD_SLAB, cs, buffer);
+ cs->mems_generation = cpuset_mems_generation++;
break;
default:
retval = -EINVAL;
if (retval == 0)
retval = nbytes;
out2:
- up(&manage_sem);
- cpuset_release_agent(pathbuf);
+ cgroup_unlock();
out1:
kfree(buffer);
return retval;
}
-static ssize_t cpuset_file_write(struct file *file, const char __user *buf,
- size_t nbytes, loff_t *ppos)
-{
- ssize_t retval = 0;
- struct cftype *cft = __d_cft(file->f_dentry);
- if (!cft)
- return -ENODEV;
-
- /* special function ? */
- if (cft->write)
- retval = cft->write(file, buf, nbytes, ppos);
- else
- retval = cpuset_common_file_write(file, buf, nbytes, ppos);
-
- return retval;
-}
-
/*
* These ascii lists should be read in a single call, by using a user
* buffer large enough to hold the entire map. If read in smaller
{
cpumask_t mask;
- down(&callback_sem);
+ mutex_lock(&callback_mutex);
mask = cs->cpus_allowed;
- up(&callback_sem);
+ mutex_unlock(&callback_mutex);
return cpulist_scnprintf(page, PAGE_SIZE, mask);
}
{
nodemask_t mask;
- down(&callback_sem);
+ mutex_lock(&callback_mutex);
mask = cs->mems_allowed;
- up(&callback_sem);
+ mutex_unlock(&callback_mutex);
return nodelist_scnprintf(page, PAGE_SIZE, mask);
}
-static ssize_t cpuset_common_file_read(struct file *file, char __user *buf,
- size_t nbytes, loff_t *ppos)
+static ssize_t cpuset_common_file_read(struct cgroup *cont,
+ struct cftype *cft,
+ struct file *file,
+ char __user *buf,
+ size_t nbytes, loff_t *ppos)
{
- struct cftype *cft = __d_cft(file->f_dentry);
- struct cpuset *cs = __d_cs(file->f_dentry->d_parent);
+ struct cpuset *cs = cgroup_cs(cont);
cpuset_filetype_t type = cft->private;
char *page;
ssize_t retval = 0;
char *s;
- if (!(page = (char *)__get_free_page(GFP_KERNEL)))
+ if (!(page = (char *)__get_free_page(GFP_TEMPORARY)))
return -ENOMEM;
s = page;
break;
case FILE_MEMLIST:
s += cpuset_sprintf_memlist(s, cs);
- break;
- case FILE_CPU_EXCLUSIVE:
- *s++ = is_cpu_exclusive(cs) ? '1' : '0';
- break;
- case FILE_MEM_EXCLUSIVE:
- *s++ = is_mem_exclusive(cs) ? '1' : '0';
- break;
- case FILE_NOTIFY_ON_RELEASE:
- *s++ = notify_on_release(cs) ? '1' : '0';
- break;
- case FILE_MEMORY_MIGRATE:
- *s++ = is_memory_migrate(cs) ? '1' : '0';
- break;
- case FILE_MEMORY_PRESSURE_ENABLED:
- *s++ = cpuset_memory_pressure_enabled ? '1' : '0';
- break;
- case FILE_MEMORY_PRESSURE:
- s += sprintf(s, "%d", fmeter_getrate(&cs->fmeter));
- break;
- default:
- retval = -EINVAL;
- goto out;
- }
- *s++ = '\n';
-
- retval = simple_read_from_buffer(buf, nbytes, ppos, page, s - page);
-out:
- free_page((unsigned long)page);
- return retval;
-}
-
-static ssize_t cpuset_file_read(struct file *file, char __user *buf, size_t nbytes,
- loff_t *ppos)
-{
- ssize_t retval = 0;
- struct cftype *cft = __d_cft(file->f_dentry);
- if (!cft)
- return -ENODEV;
-
- /* special function ? */
- if (cft->read)
- retval = cft->read(file, buf, nbytes, ppos);
- else
- retval = cpuset_common_file_read(file, buf, nbytes, ppos);
-
- return retval;
-}
-
-static int cpuset_file_open(struct inode *inode, struct file *file)
-{
- int err;
- struct cftype *cft;
-
- err = generic_file_open(inode, file);
- if (err)
- return err;
-
- cft = __d_cft(file->f_dentry);
- if (!cft)
- return -ENODEV;
- if (cft->open)
- err = cft->open(inode, file);
- else
- err = 0;
-
- return err;
-}
-
-static int cpuset_file_release(struct inode *inode, struct file *file)
-{
- struct cftype *cft = __d_cft(file->f_dentry);
- if (cft->release)
- return cft->release(inode, file);
- return 0;
-}
-
-/*
- * cpuset_rename - Only allow simple rename of directories in place.
- */
-static int cpuset_rename(struct inode *old_dir, struct dentry *old_dentry,
- struct inode *new_dir, struct dentry *new_dentry)
-{
- if (!S_ISDIR(old_dentry->d_inode->i_mode))
- return -ENOTDIR;
- if (new_dentry->d_inode)
- return -EEXIST;
- if (old_dir != new_dir)
- return -EIO;
- return simple_rename(old_dir, old_dentry, new_dir, new_dentry);
-}
-
-static struct file_operations cpuset_file_operations = {
- .read = cpuset_file_read,
- .write = cpuset_file_write,
- .llseek = generic_file_llseek,
- .open = cpuset_file_open,
- .release = cpuset_file_release,
-};
-
-static struct inode_operations cpuset_dir_inode_operations = {
- .lookup = simple_lookup,
- .mkdir = cpuset_mkdir,
- .rmdir = cpuset_rmdir,
- .rename = cpuset_rename,
-};
-
-static int cpuset_create_file(struct dentry *dentry, int mode)
-{
- struct inode *inode;
-
- if (!dentry)
- return -ENOENT;
- if (dentry->d_inode)
- return -EEXIST;
-
- inode = cpuset_new_inode(mode);
- if (!inode)
- return -ENOMEM;
-
- if (S_ISDIR(mode)) {
- inode->i_op = &cpuset_dir_inode_operations;
- inode->i_fop = &simple_dir_operations;
-
- /* start off with i_nlink == 2 (for "." entry) */
- inode->i_nlink++;
- } else if (S_ISREG(mode)) {
- inode->i_size = 0;
- inode->i_fop = &cpuset_file_operations;
- }
-
- d_instantiate(dentry, inode);
- dget(dentry); /* Extra count - pin the dentry in core */
- return 0;
-}
-
-/*
- * cpuset_create_dir - create a directory for an object.
- * cs: the cpuset we create the directory for.
- * It must have a valid ->parent field
- * And we are going to fill its ->dentry field.
- * name: The name to give to the cpuset directory. Will be copied.
- * mode: mode to set on new directory.
- */
-
-static int cpuset_create_dir(struct cpuset *cs, const char *name, int mode)
-{
- struct dentry *dentry = NULL;
- struct dentry *parent;
- int error = 0;
-
- parent = cs->parent->dentry;
- dentry = cpuset_get_dentry(parent, name);
- if (IS_ERR(dentry))
- return PTR_ERR(dentry);
- error = cpuset_create_file(dentry, S_IFDIR | mode);
- if (!error) {
- dentry->d_fsdata = cs;
- parent->d_inode->i_nlink++;
- cs->dentry = dentry;
- }
- dput(dentry);
-
- return error;
-}
-
-static int cpuset_add_file(struct dentry *dir, const struct cftype *cft)
-{
- struct dentry *dentry;
- int error;
-
- down(&dir->d_inode->i_sem);
- dentry = cpuset_get_dentry(dir, cft->name);
- if (!IS_ERR(dentry)) {
- error = cpuset_create_file(dentry, 0644 | S_IFREG);
- if (!error)
- dentry->d_fsdata = (void *)cft;
- dput(dentry);
- } else
- error = PTR_ERR(dentry);
- up(&dir->d_inode->i_sem);
- return error;
-}
-
-/*
- * Stuff for reading the 'tasks' file.
- *
- * Reading this file can return large amounts of data if a cpuset has
- * *lots* of attached tasks. So it may need several calls to read(),
- * but we cannot guarantee that the information we produce is correct
- * unless we produce it entirely atomically.
- *
- * Upon tasks file open(), a struct ctr_struct is allocated, that
- * will have a pointer to an array (also allocated here). The struct
- * ctr_struct * is stored in file->private_data. Its resources will
- * be freed by release() when the file is closed. The array is used
- * to sprintf the PIDs and then used by read().
- */
-
-/* cpusets_tasks_read array */
-
-struct ctr_struct {
- char *buf;
- int bufsz;
-};
-
-/*
- * Load into 'pidarray' up to 'npids' of the tasks using cpuset 'cs'.
- * Return actual number of pids loaded. No need to task_lock(p)
- * when reading out p->cpuset, as we don't really care if it changes
- * on the next cycle, and we are not going to try to dereference it.
- */
-static inline int pid_array_load(pid_t *pidarray, int npids, struct cpuset *cs)
-{
- int n = 0;
- struct task_struct *g, *p;
-
- read_lock(&tasklist_lock);
-
- do_each_thread(g, p) {
- if (p->cpuset == cs) {
- pidarray[n++] = p->pid;
- if (unlikely(n == npids))
- goto array_full;
- }
- } while_each_thread(g, p);
-
-array_full:
- read_unlock(&tasklist_lock);
- return n;
-}
-
-static int cmppid(const void *a, const void *b)
-{
- return *(pid_t *)a - *(pid_t *)b;
-}
-
-/*
- * Convert array 'a' of 'npids' pid_t's to a string of newline separated
- * decimal pids in 'buf'. Don't write more than 'sz' chars, but return
- * count 'cnt' of how many chars would be written if buf were large enough.
- */
-static int pid_array_to_buf(char *buf, int sz, pid_t *a, int npids)
-{
- int cnt = 0;
- int i;
-
- for (i = 0; i < npids; i++)
- cnt += snprintf(buf + cnt, max(sz - cnt, 0), "%d\n", a[i]);
- return cnt;
-}
-
-/*
- * Handle an open on 'tasks' file. Prepare a buffer listing the
- * process id's of tasks currently attached to the cpuset being opened.
- *
- * Does not require any specific cpuset semaphores, and does not take any.
- */
-static int cpuset_tasks_open(struct inode *unused, struct file *file)
-{
- struct cpuset *cs = __d_cs(file->f_dentry->d_parent);
- struct ctr_struct *ctr;
- pid_t *pidarray;
- int npids;
- char c;
-
- if (!(file->f_mode & FMODE_READ))
- return 0;
-
- ctr = kmalloc(sizeof(*ctr), GFP_KERNEL);
- if (!ctr)
- goto err0;
-
- /*
- * If cpuset gets more users after we read count, we won't have
- * enough space - tough. This race is indistinguishable to the
- * caller from the case that the additional cpuset users didn't
- * show up until sometime later on.
- */
- npids = atomic_read(&cs->count);
- pidarray = kmalloc(npids * sizeof(pid_t), GFP_KERNEL);
- if (!pidarray)
- goto err1;
-
- npids = pid_array_load(pidarray, npids, cs);
- sort(pidarray, npids, sizeof(pid_t), cmppid, NULL);
-
- /* Call pid_array_to_buf() twice, first just to get bufsz */
- ctr->bufsz = pid_array_to_buf(&c, sizeof(c), pidarray, npids) + 1;
- ctr->buf = kmalloc(ctr->bufsz, GFP_KERNEL);
- if (!ctr->buf)
- goto err2;
- ctr->bufsz = pid_array_to_buf(ctr->buf, ctr->bufsz, pidarray, npids);
-
- kfree(pidarray);
- file->private_data = ctr;
- return 0;
+ break;
+ case FILE_CPU_EXCLUSIVE:
+ *s++ = is_cpu_exclusive(cs) ? '1' : '0';
+ break;
+ case FILE_MEM_EXCLUSIVE:
+ *s++ = is_mem_exclusive(cs) ? '1' : '0';
+ break;
+ case FILE_SCHED_LOAD_BALANCE:
+ *s++ = is_sched_load_balance(cs) ? '1' : '0';
+ break;
+ case FILE_MEMORY_MIGRATE:
+ *s++ = is_memory_migrate(cs) ? '1' : '0';
+ break;
+ case FILE_MEMORY_PRESSURE_ENABLED:
+ *s++ = cpuset_memory_pressure_enabled ? '1' : '0';
+ break;
+ case FILE_MEMORY_PRESSURE:
+ s += sprintf(s, "%d", fmeter_getrate(&cs->fmeter));
+ break;
+ case FILE_SPREAD_PAGE:
+ *s++ = is_spread_page(cs) ? '1' : '0';
+ break;
+ case FILE_SPREAD_SLAB:
+ *s++ = is_spread_slab(cs) ? '1' : '0';
+ break;
+ default:
+ retval = -EINVAL;
+ goto out;
+ }
+ *s++ = '\n';
-err2:
- kfree(pidarray);
-err1:
- kfree(ctr);
-err0:
- return -ENOMEM;
+ retval = simple_read_from_buffer(buf, nbytes, ppos, page, s - page);
+out:
+ free_page((unsigned long)page);
+ return retval;
}
-static ssize_t cpuset_tasks_read(struct file *file, char __user *buf,
- size_t nbytes, loff_t *ppos)
-{
- struct ctr_struct *ctr = file->private_data;
- if (*ppos + nbytes > ctr->bufsz)
- nbytes = ctr->bufsz - *ppos;
- if (copy_to_user(buf, ctr->buf + *ppos, nbytes))
- return -EFAULT;
- *ppos += nbytes;
- return nbytes;
-}
-static int cpuset_tasks_release(struct inode *unused_inode, struct file *file)
-{
- struct ctr_struct *ctr;
- if (file->f_mode & FMODE_READ) {
- ctr = file->private_data;
- kfree(ctr->buf);
- kfree(ctr);
- }
- return 0;
-}
/*
* for the common functions, 'private' gives the type of file
*/
-static struct cftype cft_tasks = {
- .name = "tasks",
- .open = cpuset_tasks_open,
- .read = cpuset_tasks_read,
- .release = cpuset_tasks_release,
- .private = FILE_TASKLIST,
-};
-
static struct cftype cft_cpus = {
.name = "cpus",
+ .read = cpuset_common_file_read,
+ .write = cpuset_common_file_write,
.private = FILE_CPULIST,
};
static struct cftype cft_mems = {
.name = "mems",
+ .read = cpuset_common_file_read,
+ .write = cpuset_common_file_write,
.private = FILE_MEMLIST,
};
static struct cftype cft_cpu_exclusive = {
.name = "cpu_exclusive",
+ .read = cpuset_common_file_read,
+ .write = cpuset_common_file_write,
.private = FILE_CPU_EXCLUSIVE,
};
static struct cftype cft_mem_exclusive = {
.name = "mem_exclusive",
+ .read = cpuset_common_file_read,
+ .write = cpuset_common_file_write,
.private = FILE_MEM_EXCLUSIVE,
};
-static struct cftype cft_notify_on_release = {
- .name = "notify_on_release",
- .private = FILE_NOTIFY_ON_RELEASE,
+static struct cftype cft_sched_load_balance = {
+ .name = "sched_load_balance",
+ .read = cpuset_common_file_read,
+ .write = cpuset_common_file_write,
+ .private = FILE_SCHED_LOAD_BALANCE,
};
static struct cftype cft_memory_migrate = {
.name = "memory_migrate",
+ .read = cpuset_common_file_read,
+ .write = cpuset_common_file_write,
.private = FILE_MEMORY_MIGRATE,
};
static struct cftype cft_memory_pressure_enabled = {
.name = "memory_pressure_enabled",
+ .read = cpuset_common_file_read,
+ .write = cpuset_common_file_write,
.private = FILE_MEMORY_PRESSURE_ENABLED,
};
static struct cftype cft_memory_pressure = {
.name = "memory_pressure",
+ .read = cpuset_common_file_read,
+ .write = cpuset_common_file_write,
.private = FILE_MEMORY_PRESSURE,
};
-static int cpuset_populate_dir(struct dentry *cs_dentry)
+static struct cftype cft_spread_page = {
+ .name = "memory_spread_page",
+ .read = cpuset_common_file_read,
+ .write = cpuset_common_file_write,
+ .private = FILE_SPREAD_PAGE,
+};
+
+static struct cftype cft_spread_slab = {
+ .name = "memory_spread_slab",
+ .read = cpuset_common_file_read,
+ .write = cpuset_common_file_write,
+ .private = FILE_SPREAD_SLAB,
+};
+
+static int cpuset_populate(struct cgroup_subsys *ss, struct cgroup *cont)
{
int err;
- if ((err = cpuset_add_file(cs_dentry, &cft_cpus)) < 0)
+ if ((err = cgroup_add_file(cont, ss, &cft_cpus)) < 0)
return err;
- if ((err = cpuset_add_file(cs_dentry, &cft_mems)) < 0)
+ if ((err = cgroup_add_file(cont, ss, &cft_mems)) < 0)
return err;
- if ((err = cpuset_add_file(cs_dentry, &cft_cpu_exclusive)) < 0)
+ if ((err = cgroup_add_file(cont, ss, &cft_cpu_exclusive)) < 0)
return err;
- if ((err = cpuset_add_file(cs_dentry, &cft_mem_exclusive)) < 0)
+ if ((err = cgroup_add_file(cont, ss, &cft_mem_exclusive)) < 0)
return err;
- if ((err = cpuset_add_file(cs_dentry, &cft_notify_on_release)) < 0)
+ if ((err = cgroup_add_file(cont, ss, &cft_memory_migrate)) < 0)
return err;
- if ((err = cpuset_add_file(cs_dentry, &cft_memory_migrate)) < 0)
+ if ((err = cgroup_add_file(cont, ss, &cft_sched_load_balance)) < 0)
return err;
- if ((err = cpuset_add_file(cs_dentry, &cft_memory_pressure)) < 0)
+ if ((err = cgroup_add_file(cont, ss, &cft_memory_pressure)) < 0)
return err;
- if ((err = cpuset_add_file(cs_dentry, &cft_tasks)) < 0)
+ if ((err = cgroup_add_file(cont, ss, &cft_spread_page)) < 0)
return err;
+ if ((err = cgroup_add_file(cont, ss, &cft_spread_slab)) < 0)
+ return err;
+ /* memory_pressure_enabled is in root cpuset only */
+ if (err == 0 && !cont->parent)
+ err = cgroup_add_file(cont, ss,
+ &cft_memory_pressure_enabled);
return 0;
}
+/*
+ * post_clone() is called at the end of cgroup_clone().
+ * 'cgroup' was just created automatically as a result of
+ * a cgroup_clone(), and the current task is about to
+ * be moved into 'cgroup'.
+ *
+ * Currently we refuse to set up the cgroup - thereby
+ * refusing the task to be entered, and as a result refusing
+ * the sys_unshare() or clone() which initiated it - if any
+ * sibling cpusets have exclusive cpus or mem.
+ *
+ * If this becomes a problem for some users who wish to
+ * allow that scenario, then cpuset_post_clone() could be
+ * changed to grant parent->cpus_allowed-sibling_cpus_exclusive
+ * (and likewise for mems) to the new cgroup. Called with cgroup_mutex
+ * held.
+ */
+static void cpuset_post_clone(struct cgroup_subsys *ss,
+ struct cgroup *cgroup)
+{
+ struct cgroup *parent, *child;
+ struct cpuset *cs, *parent_cs;
+
+ parent = cgroup->parent;
+ list_for_each_entry(child, &parent->children, sibling) {
+ cs = cgroup_cs(child);
+ if (is_mem_exclusive(cs) || is_cpu_exclusive(cs))
+ return;
+ }
+ cs = cgroup_cs(cgroup);
+ parent_cs = cgroup_cs(parent);
+
+ cs->mems_allowed = parent_cs->mems_allowed;
+ cs->cpus_allowed = parent_cs->cpus_allowed;
+ return;
+}
+
/*
* cpuset_create - create a cpuset
- * parent: cpuset that will be parent of the new cpuset.
- * name: name of the new cpuset. Will be strcpy'ed.
- * mode: mode to set on new inode
- *
- * Must be called with the semaphore on the parent inode held
+ * ss: cpuset cgroup subsystem
+ * cont: control group that the new cpuset will be part of
*/
-static long cpuset_create(struct cpuset *parent, const char *name, int mode)
+static struct cgroup_subsys_state *cpuset_create(
+ struct cgroup_subsys *ss,
+ struct cgroup *cont)
{
struct cpuset *cs;
- int err;
+ struct cpuset *parent;
+ if (!cont->parent) {
+ /* This is early initialization for the top cgroup */
+ top_cpuset.mems_generation = cpuset_mems_generation++;
+ return &top_cpuset.css;
+ }
+ parent = cgroup_cs(cont->parent);
cs = kmalloc(sizeof(*cs), GFP_KERNEL);
if (!cs)
- return -ENOMEM;
+ return ERR_PTR(-ENOMEM);
- down(&manage_sem);
- refresh_mems();
+ cpuset_update_task_memory_state();
cs->flags = 0;
- if (notify_on_release(parent))
- set_bit(CS_NOTIFY_ON_RELEASE, &cs->flags);
+ if (is_spread_page(parent))
+ set_bit(CS_SPREAD_PAGE, &cs->flags);
+ if (is_spread_slab(parent))
+ set_bit(CS_SPREAD_SLAB, &cs->flags);
+ set_bit(CS_SCHED_LOAD_BALANCE, &cs->flags);
cs->cpus_allowed = CPU_MASK_NONE;
cs->mems_allowed = NODE_MASK_NONE;
- atomic_set(&cs->count, 0);
- INIT_LIST_HEAD(&cs->sibling);
- INIT_LIST_HEAD(&cs->children);
- atomic_inc(&cpuset_mems_generation);
- cs->mems_generation = atomic_read(&cpuset_mems_generation);
+ cs->mems_generation = cpuset_mems_generation++;
fmeter_init(&cs->fmeter);
cs->parent = parent;
+ number_of_cpusets++;
+ return &cs->css ;
+}
- down(&callback_sem);
- list_add(&cs->sibling, &cs->parent->children);
- up(&callback_sem);
+/*
+ * Locking note on the strange update_flag() call below:
+ *
+ * If the cpuset being removed has its flag 'sched_load_balance'
+ * enabled, then simulate turning sched_load_balance off, which
+ * will call rebuild_sched_domains(). The get_online_cpus()
+ * call in rebuild_sched_domains() must not be made while holding
+ * callback_mutex. Elsewhere the kernel nests callback_mutex inside
+ * get_online_cpus() calls. So the reverse nesting would risk an
+ * ABBA deadlock.
+ */
- err = cpuset_create_dir(cs, name, mode);
- if (err < 0)
- goto err;
+static void cpuset_destroy(struct cgroup_subsys *ss, struct cgroup *cont)
+{
+ struct cpuset *cs = cgroup_cs(cont);
- /*
- * Release manage_sem before cpuset_populate_dir() because it
- * will down() this new directory's i_sem and if we race with
- * another mkdir, we might deadlock.
- */
- up(&manage_sem);
+ cpuset_update_task_memory_state();
- err = cpuset_populate_dir(cs->dentry);
- /* If err < 0, we have a half-filled directory - oh well ;) */
- return 0;
-err:
- list_del(&cs->sibling);
- up(&manage_sem);
+ if (is_sched_load_balance(cs))
+ update_flag(CS_SCHED_LOAD_BALANCE, cs, "0");
+
+ number_of_cpusets--;
kfree(cs);
- return err;
}
-static int cpuset_mkdir(struct inode *dir, struct dentry *dentry, int mode)
-{
- struct cpuset *c_parent = dentry->d_parent->d_fsdata;
+struct cgroup_subsys cpuset_subsys = {
+ .name = "cpuset",
+ .create = cpuset_create,
+ .destroy = cpuset_destroy,
+ .can_attach = cpuset_can_attach,
+ .attach = cpuset_attach,
+ .populate = cpuset_populate,
+ .post_clone = cpuset_post_clone,
+ .subsys_id = cpuset_subsys_id,
+ .early_init = 1,
+};
- /* the vfs holds inode->i_sem already */
- return cpuset_create(c_parent, dentry->d_name.name, mode | S_IFDIR);
-}
+/*
+ * cpuset_init_early - just enough so that the calls to
+ * cpuset_update_task_memory_state() in early init code
+ * are harmless.
+ */
-static int cpuset_rmdir(struct inode *unused_dir, struct dentry *dentry)
+int __init cpuset_init_early(void)
{
- struct cpuset *cs = dentry->d_fsdata;
- struct dentry *d;
- struct cpuset *parent;
- char *pathbuf = NULL;
-
- /* the vfs holds both inode->i_sem already */
-
- down(&manage_sem);
- refresh_mems();
- if (atomic_read(&cs->count) > 0) {
- up(&manage_sem);
- return -EBUSY;
- }
- if (!list_empty(&cs->children)) {
- up(&manage_sem);
- return -EBUSY;
- }
- parent = cs->parent;
- down(&callback_sem);
- set_bit(CS_REMOVED, &cs->flags);
- if (is_cpu_exclusive(cs))
- update_cpu_domains(cs);
- list_del(&cs->sibling); /* delete my sibling from parent->children */
- spin_lock(&cs->dentry->d_lock);
- d = dget(cs->dentry);
- cs->dentry = NULL;
- spin_unlock(&d->d_lock);
- cpuset_d_remove_dir(d);
- dput(d);
- up(&callback_sem);
- if (list_empty(&parent->children))
- check_for_release(parent, &pathbuf);
- up(&manage_sem);
- cpuset_release_agent(pathbuf);
+ top_cpuset.mems_generation = cpuset_mems_generation++;
return 0;
}
+
/**
* cpuset_init - initialize cpusets at system boot
*
int __init cpuset_init(void)
{
- struct dentry *root;
- int err;
+ int err = 0;
top_cpuset.cpus_allowed = CPU_MASK_ALL;
top_cpuset.mems_allowed = NODE_MASK_ALL;
fmeter_init(&top_cpuset.fmeter);
- atomic_inc(&cpuset_mems_generation);
- top_cpuset.mems_generation = atomic_read(&cpuset_mems_generation);
-
- init_task.cpuset = &top_cpuset;
+ top_cpuset.mems_generation = cpuset_mems_generation++;
+ set_bit(CS_SCHED_LOAD_BALANCE, &top_cpuset.flags);
err = register_filesystem(&cpuset_fs_type);
if (err < 0)
- goto out;
- cpuset_mount = kern_mount(&cpuset_fs_type);
- if (IS_ERR(cpuset_mount)) {
- printk(KERN_ERR "cpuset: could not mount!\n");
- err = PTR_ERR(cpuset_mount);
- cpuset_mount = NULL;
- goto out;
- }
- root = cpuset_mount->mnt_sb->s_root;
- root->d_fsdata = &top_cpuset;
- root->d_inode->i_nlink++;
- top_cpuset.dentry = root;
- root->d_inode->i_op = &cpuset_dir_inode_operations;
- err = cpuset_populate_dir(root);
- /* memory_pressure_enabled is in root cpuset only */
- if (err == 0)
- err = cpuset_add_file(root, &cft_memory_pressure_enabled);
-out:
- return err;
+ return err;
+
+ number_of_cpusets = 1;
+ return 0;
}
/**
- * cpuset_init_smp - initialize cpus_allowed
+ * cpuset_do_move_task - move a given task to another cpuset
+ * @tsk: pointer to task_struct the task to move
+ * @scan: struct cgroup_scanner contained in its struct cpuset_hotplug_scanner
*
- * Description: Finish top cpuset after cpu, node maps are initialized
- **/
-
-void __init cpuset_init_smp(void)
+ * Called by cgroup_scan_tasks() for each task in a cgroup.
+ * Return nonzero to stop the walk through the tasks.
+ */
+void cpuset_do_move_task(struct task_struct *tsk, struct cgroup_scanner *scan)
{
- top_cpuset.cpus_allowed = cpu_online_map;
- top_cpuset.mems_allowed = node_online_map;
+ struct cpuset_hotplug_scanner *chsp;
+
+ chsp = container_of(scan, struct cpuset_hotplug_scanner, scan);
+ cgroup_attach_task(chsp->to, tsk);
}
/**
- * cpuset_fork - attach newly forked task to its parents cpuset.
- * @tsk: pointer to task_struct of forking parent process.
+ * move_member_tasks_to_cpuset - move tasks from one cpuset to another
+ * @from: cpuset in which the tasks currently reside
+ * @to: cpuset to which the tasks will be moved
*
- * Description: A task inherits its parent's cpuset at fork().
+ * Called with cgroup_mutex held
+ * callback_mutex must not be held, as cpuset_attach() will take it.
*
- * A pointer to the shared cpuset was automatically copied in fork.c
- * by dup_task_struct(). However, we ignore that copy, since it was
- * not made under the protection of task_lock(), so might no longer be
- * a valid cpuset pointer. attach_task() might have already changed
- * current->cpuset, allowing the previously referenced cpuset to
- * be removed and freed. Instead, we task_lock(current) and copy
- * its present value of current->cpuset for our freshly forked child.
- *
- * At the point that cpuset_fork() is called, 'current' is the parent
- * task, and the passed argument 'child' points to the child task.
- **/
+ * The cgroup_scan_tasks() function will scan all the tasks in a cgroup,
+ * calling callback functions for each.
+ */
+static void move_member_tasks_to_cpuset(struct cpuset *from, struct cpuset *to)
+{
+ struct cpuset_hotplug_scanner scan;
-void cpuset_fork(struct task_struct *child)
+ scan.scan.cg = from->css.cgroup;
+ scan.scan.test_task = NULL; /* select all tasks in cgroup */
+ scan.scan.process_task = cpuset_do_move_task;
+ scan.scan.heap = NULL;
+ scan.to = to->css.cgroup;
+
+ if (cgroup_scan_tasks((struct cgroup_scanner *)&scan))
+ printk(KERN_ERR "move_member_tasks_to_cpuset: "
+ "cgroup_scan_tasks failed\n");
+}
+
+/*
+ * If common_cpu_mem_hotplug_unplug(), below, unplugs any CPUs
+ * or memory nodes, we need to walk over the cpuset hierarchy,
+ * removing that CPU or node from all cpusets. If this removes the
+ * last CPU or node from a cpuset, then move the tasks in the empty
+ * cpuset to its next-highest non-empty parent.
+ *
+ * Called with cgroup_mutex held
+ * callback_mutex must not be held, as cpuset_attach() will take it.
+ */
+static void remove_tasks_in_empty_cpuset(struct cpuset *cs)
{
- task_lock(current);
- child->cpuset = current->cpuset;
- atomic_inc(&child->cpuset->count);
- task_unlock(current);
+ struct cpuset *parent;
+
+ /*
+ * The cgroup's css_sets list is in use if there are tasks
+ * in the cpuset; the list is empty if there are none;
+ * the cs->css.refcnt seems always 0.
+ */
+ if (list_empty(&cs->css.cgroup->css_sets))
+ return;
+
+ /*
+ * Find its next-highest non-empty parent, (top cpuset
+ * has online cpus, so can't be empty).
+ */
+ parent = cs->parent;
+ while (cpus_empty(parent->cpus_allowed) ||
+ nodes_empty(parent->mems_allowed))
+ parent = parent->parent;
+
+ move_member_tasks_to_cpuset(cs, parent);
}
-/**
- * cpuset_exit - detach cpuset from exiting task
- * @tsk: pointer to task_struct of exiting process
- *
- * Description: Detach cpuset from @tsk and release it.
+/*
+ * Walk the specified cpuset subtree and look for empty cpusets.
+ * The tasks of such cpuset must be moved to a parent cpuset.
*
- * Note that cpusets marked notify_on_release force every task in
- * them to take the global manage_sem semaphore when exiting.
- * This could impact scaling on very large systems. Be reluctant to
- * use notify_on_release cpusets where very high task exit scaling
- * is required on large systems.
+ * Called with cgroup_mutex held. We take callback_mutex to modify
+ * cpus_allowed and mems_allowed.
*
- * Don't even think about derefencing 'cs' after the cpuset use count
- * goes to zero, except inside a critical section guarded by manage_sem
- * or callback_sem. Otherwise a zero cpuset use count is a license to
- * any other task to nuke the cpuset immediately, via cpuset_rmdir().
+ * This walk processes the tree from top to bottom, completing one layer
+ * before dropping down to the next. It always processes a node before
+ * any of its children.
*
- * This routine has to take manage_sem, not callback_sem, because
- * it is holding that semaphore while calling check_for_release(),
- * which calls kmalloc(), so can't be called holding callback__sem().
+ * For now, since we lack memory hot unplug, we'll never see a cpuset
+ * that has tasks along with an empty 'mems'. But if we did see such
+ * a cpuset, we'd handle it just like we do if its 'cpus' was empty.
+ */
+static void scan_for_empty_cpusets(const struct cpuset *root)
+{
+ struct cpuset *cp; /* scans cpusets being updated */
+ struct cpuset *child; /* scans child cpusets of cp */
+ struct list_head queue;
+ struct cgroup *cont;
+
+ INIT_LIST_HEAD(&queue);
+
+ list_add_tail((struct list_head *)&root->stack_list, &queue);
+
+ while (!list_empty(&queue)) {
+ cp = container_of(queue.next, struct cpuset, stack_list);
+ list_del(queue.next);
+ list_for_each_entry(cont, &cp->css.cgroup->children, sibling) {
+ child = cgroup_cs(cont);
+ list_add_tail(&child->stack_list, &queue);
+ }
+ cont = cp->css.cgroup;
+
+ /* Continue past cpusets with all cpus, mems online */
+ if (cpus_subset(cp->cpus_allowed, cpu_online_map) &&
+ nodes_subset(cp->mems_allowed, node_states[N_HIGH_MEMORY]))
+ continue;
+
+ /* Remove offline cpus and mems from this cpuset. */
+ mutex_lock(&callback_mutex);
+ cpus_and(cp->cpus_allowed, cp->cpus_allowed, cpu_online_map);
+ nodes_and(cp->mems_allowed, cp->mems_allowed,
+ node_states[N_HIGH_MEMORY]);
+ mutex_unlock(&callback_mutex);
+
+ /* Move tasks from the empty cpuset to a parent */
+ if (cpus_empty(cp->cpus_allowed) ||
+ nodes_empty(cp->mems_allowed))
+ remove_tasks_in_empty_cpuset(cp);
+ }
+}
+
+/*
+ * The cpus_allowed and mems_allowed nodemasks in the top_cpuset track
+ * cpu_online_map and node_states[N_HIGH_MEMORY]. Force the top cpuset to
+ * track what's online after any CPU or memory node hotplug or unplug event.
+ *
+ * Since there are two callers of this routine, one for CPU hotplug
+ * events and one for memory node hotplug events, we could have coded
+ * two separate routines here. We code it as a single common routine
+ * in order to minimize text size.
+ */
+
+static void common_cpu_mem_hotplug_unplug(void)
+{
+ cgroup_lock();
+
+ top_cpuset.cpus_allowed = cpu_online_map;
+ top_cpuset.mems_allowed = node_states[N_HIGH_MEMORY];
+ scan_for_empty_cpusets(&top_cpuset);
+
+ cgroup_unlock();
+}
+
+/*
+ * The top_cpuset tracks what CPUs and Memory Nodes are online,
+ * period. This is necessary in order to make cpusets transparent
+ * (of no affect) on systems that are actively using CPU hotplug
+ * but making no active use of cpusets.
*
- * We don't need to task_lock() this reference to tsk->cpuset,
- * because tsk is already marked PF_EXITING, so attach_task() won't
- * mess with it.
- **/
+ * This routine ensures that top_cpuset.cpus_allowed tracks
+ * cpu_online_map on each CPU hotplug (cpuhp) event.
+ */
-void cpuset_exit(struct task_struct *tsk)
+static int cpuset_handle_cpuhp(struct notifier_block *unused_nb,
+ unsigned long phase, void *unused_cpu)
{
- struct cpuset *cs;
+ if (phase == CPU_DYING || phase == CPU_DYING_FROZEN)
+ return NOTIFY_DONE;
- BUG_ON(!(tsk->flags & PF_EXITING));
+ common_cpu_mem_hotplug_unplug();
+ return 0;
+}
- cs = tsk->cpuset;
- tsk->cpuset = NULL;
+#ifdef CONFIG_MEMORY_HOTPLUG
+/*
+ * Keep top_cpuset.mems_allowed tracking node_states[N_HIGH_MEMORY].
+ * Call this routine anytime after you change
+ * node_states[N_HIGH_MEMORY].
+ * See also the previous routine cpuset_handle_cpuhp().
+ */
- if (notify_on_release(cs)) {
- char *pathbuf = NULL;
+void cpuset_track_online_nodes(void)
+{
+ common_cpu_mem_hotplug_unplug();
+}
+#endif
- down(&manage_sem);
- if (atomic_dec_and_test(&cs->count))
- check_for_release(cs, &pathbuf);
- up(&manage_sem);
- cpuset_release_agent(pathbuf);
- } else {
- atomic_dec(&cs->count);
- }
+/**
+ * cpuset_init_smp - initialize cpus_allowed
+ *
+ * Description: Finish top cpuset after cpu, node maps are initialized
+ **/
+
+void __init cpuset_init_smp(void)
+{
+ top_cpuset.cpus_allowed = cpu_online_map;
+ top_cpuset.mems_allowed = node_states[N_HIGH_MEMORY];
+
+ hotcpu_notifier(cpuset_handle_cpuhp, 0);
}
/**
+
* cpuset_cpus_allowed - return cpus_allowed mask from a tasks cpuset.
* @tsk: pointer to task_struct from which to obtain cpuset->cpus_allowed.
*
* tasks cpuset.
**/
-cpumask_t cpuset_cpus_allowed(const struct task_struct *tsk)
+cpumask_t cpuset_cpus_allowed(struct task_struct *tsk)
+{
+ cpumask_t mask;
+
+ mutex_lock(&callback_mutex);
+ mask = cpuset_cpus_allowed_locked(tsk);
+ mutex_unlock(&callback_mutex);
+
+ return mask;
+}
+
+/**
+ * cpuset_cpus_allowed_locked - return cpus_allowed mask from a tasks cpuset.
+ * Must be called with callback_mutex held.
+ **/
+cpumask_t cpuset_cpus_allowed_locked(struct task_struct *tsk)
{
cpumask_t mask;
- down(&callback_sem);
- task_lock((struct task_struct *)tsk);
- guarantee_online_cpus(tsk->cpuset, &mask);
- task_unlock((struct task_struct *)tsk);
- up(&callback_sem);
+ task_lock(tsk);
+ guarantee_online_cpus(task_cs(tsk), &mask);
+ task_unlock(tsk);
return mask;
}
}
/**
- * cpuset_update_current_mems_allowed - update mems parameters to new values
- *
- * If the current tasks cpusets mems_allowed changed behind our backs,
- * update current->mems_allowed and mems_generation to the new value.
- * Do not call this routine if in_interrupt().
+ * cpuset_mems_allowed - return mems_allowed mask from a tasks cpuset.
+ * @tsk: pointer to task_struct from which to obtain cpuset->mems_allowed.
*
- * Call without callback_sem or task_lock() held. May be called
- * with or without manage_sem held. Unless exiting, it will acquire
- * task_lock(). Also might acquire callback_sem during call to
- * refresh_mems().
- */
+ * Description: Returns the nodemask_t mems_allowed of the cpuset
+ * attached to the specified @tsk. Guaranteed to return some non-empty
+ * subset of node_states[N_HIGH_MEMORY], even if this means going outside the
+ * tasks cpuset.
+ **/
-void cpuset_update_current_mems_allowed(void)
+nodemask_t cpuset_mems_allowed(struct task_struct *tsk)
{
- struct cpuset *cs;
- int need_to_refresh = 0;
+ nodemask_t mask;
- task_lock(current);
- cs = current->cpuset;
- if (!cs)
- goto done;
- if (current->cpuset_mems_generation != cs->mems_generation)
- need_to_refresh = 1;
-done:
- task_unlock(current);
- if (need_to_refresh)
- refresh_mems();
+ mutex_lock(&callback_mutex);
+ task_lock(tsk);
+ guarantee_online_mems(task_cs(tsk), &mask);
+ task_unlock(tsk);
+ mutex_unlock(&callback_mutex);
+
+ return mask;
}
/**
int i;
for (i = 0; zl->zones[i]; i++) {
- int nid = zl->zones[i]->zone_pgdat->node_id;
+ int nid = zone_to_nid(zl->zones[i]);
if (node_isset(nid, current->mems_allowed))
return 1;
/*
* nearest_exclusive_ancestor() - Returns the nearest mem_exclusive
- * ancestor to the specified cpuset. Call holding callback_sem.
+ * ancestor to the specified cpuset. Call holding callback_mutex.
* If no ancestor is mem_exclusive (an unusual configuration), then
* returns the root cpuset.
*/
}
/**
- * cpuset_zone_allowed - Can we allocate memory on zone z's memory node?
+ * cpuset_zone_allowed_softwall - Can we allocate on zone z's memory node?
* @z: is this zone on an allowed node?
- * @gfp_mask: memory allocation flags (we use __GFP_HARDWALL)
+ * @gfp_mask: memory allocation flags
*
- * If we're in interrupt, yes, we can always allocate. If zone
+ * If we're in interrupt, yes, we can always allocate. If
+ * __GFP_THISNODE is set, yes, we can always allocate. If zone
* z's node is in our tasks mems_allowed, yes. If it's not a
* __GFP_HARDWALL request and this zone's nodes is in the nearest
* mem_exclusive cpuset ancestor to this tasks cpuset, yes.
+ * If the task has been OOM killed and has access to memory reserves
+ * as specified by the TIF_MEMDIE flag, yes.
* Otherwise, no.
*
+ * If __GFP_HARDWALL is set, cpuset_zone_allowed_softwall()
+ * reduces to cpuset_zone_allowed_hardwall(). Otherwise,
+ * cpuset_zone_allowed_softwall() might sleep, and might allow a zone
+ * from an enclosing cpuset.
+ *
+ * cpuset_zone_allowed_hardwall() only handles the simpler case of
+ * hardwall cpusets, and never sleeps.
+ *
+ * The __GFP_THISNODE placement logic is really handled elsewhere,
+ * by forcibly using a zonelist starting at a specified node, and by
+ * (in get_page_from_freelist()) refusing to consider the zones for
+ * any node on the zonelist except the first. By the time any such
+ * calls get to this routine, we should just shut up and say 'yes'.
+ *
* GFP_USER allocations are marked with the __GFP_HARDWALL bit,
- * and do not allow allocations outside the current tasks cpuset.
+ * and do not allow allocations outside the current tasks cpuset
+ * unless the task has been OOM killed as is marked TIF_MEMDIE.
* GFP_KERNEL allocations are not so marked, so can escape to the
- * nearest mem_exclusive ancestor cpuset.
- *
- * Scanning up parent cpusets requires callback_sem. The __alloc_pages()
- * routine only calls here with __GFP_HARDWALL bit _not_ set if
- * it's a GFP_KERNEL allocation, and all nodes in the current tasks
- * mems_allowed came up empty on the first pass over the zonelist.
- * So only GFP_KERNEL allocations, if all nodes in the cpuset are
- * short of memory, might require taking the callback_sem semaphore.
- *
- * The first loop over the zonelist in mm/page_alloc.c:__alloc_pages()
- * calls here with __GFP_HARDWALL always set in gfp_mask, enforcing
- * hardwall cpusets - no allocation on a node outside the cpuset is
- * allowed (unless in interrupt, of course).
- *
- * The second loop doesn't even call here for GFP_ATOMIC requests
- * (if the __alloc_pages() local variable 'wait' is set). That check
- * and the checks below have the combined affect in the second loop of
- * the __alloc_pages() routine that:
+ * nearest enclosing mem_exclusive ancestor cpuset.
+ *
+ * Scanning up parent cpusets requires callback_mutex. The
+ * __alloc_pages() routine only calls here with __GFP_HARDWALL bit
+ * _not_ set if it's a GFP_KERNEL allocation, and all nodes in the
+ * current tasks mems_allowed came up empty on the first pass over
+ * the zonelist. So only GFP_KERNEL allocations, if all nodes in the
+ * cpuset are short of memory, might require taking the callback_mutex
+ * mutex.
+ *
+ * The first call here from mm/page_alloc:get_page_from_freelist()
+ * has __GFP_HARDWALL set in gfp_mask, enforcing hardwall cpusets,
+ * so no allocation on a node outside the cpuset is allowed (unless
+ * in interrupt, of course).
+ *
+ * The second pass through get_page_from_freelist() doesn't even call
+ * here for GFP_ATOMIC calls. For those calls, the __alloc_pages()
+ * variable 'wait' is not set, and the bit ALLOC_CPUSET is not set
+ * in alloc_flags. That logic and the checks below have the combined
+ * affect that:
* in_interrupt - any node ok (current task context irrelevant)
* GFP_ATOMIC - any node ok
+ * TIF_MEMDIE - any node ok
* GFP_KERNEL - any node in enclosing mem_exclusive cpuset ok
* GFP_USER - only nodes in current tasks mems allowed ok.
- **/
+ *
+ * Rule:
+ * Don't call cpuset_zone_allowed_softwall if you can't sleep, unless you
+ * pass in the __GFP_HARDWALL flag set in gfp_flag, which disables
+ * the code that might scan up ancestor cpusets and sleep.
+ */
-int cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask)
+int __cpuset_zone_allowed_softwall(struct zone *z, gfp_t gfp_mask)
{
int node; /* node that zone z is on */
const struct cpuset *cs; /* current cpuset ancestors */
- int allowed = 1; /* is allocation in zone z allowed? */
+ int allowed; /* is allocation in zone z allowed? */
- if (in_interrupt())
+ if (in_interrupt() || (gfp_mask & __GFP_THISNODE))
return 1;
- node = z->zone_pgdat->node_id;
+ node = zone_to_nid(z);
+ might_sleep_if(!(gfp_mask & __GFP_HARDWALL));
if (node_isset(node, current->mems_allowed))
return 1;
+ /*
+ * Allow tasks that have access to memory reserves because they have
+ * been OOM killed to get memory anywhere.
+ */
+ if (unlikely(test_thread_flag(TIF_MEMDIE)))
+ return 1;
if (gfp_mask & __GFP_HARDWALL) /* If hardwall request, stop here */
return 0;
return 1;
/* Not hardwall and node outside mems_allowed: scan up cpusets */
- down(&callback_sem);
+ mutex_lock(&callback_mutex);
task_lock(current);
- cs = nearest_exclusive_ancestor(current->cpuset);
+ cs = nearest_exclusive_ancestor(task_cs(current));
task_unlock(current);
allowed = node_isset(node, cs->mems_allowed);
- up(&callback_sem);
+ mutex_unlock(&callback_mutex);
return allowed;
}
+/*
+ * cpuset_zone_allowed_hardwall - Can we allocate on zone z's memory node?
+ * @z: is this zone on an allowed node?
+ * @gfp_mask: memory allocation flags
+ *
+ * If we're in interrupt, yes, we can always allocate.
+ * If __GFP_THISNODE is set, yes, we can always allocate. If zone
+ * z's node is in our tasks mems_allowed, yes. If the task has been
+ * OOM killed and has access to memory reserves as specified by the
+ * TIF_MEMDIE flag, yes. Otherwise, no.
+ *
+ * The __GFP_THISNODE placement logic is really handled elsewhere,
+ * by forcibly using a zonelist starting at a specified node, and by
+ * (in get_page_from_freelist()) refusing to consider the zones for
+ * any node on the zonelist except the first. By the time any such
+ * calls get to this routine, we should just shut up and say 'yes'.
+ *
+ * Unlike the cpuset_zone_allowed_softwall() variant, above,
+ * this variant requires that the zone be in the current tasks
+ * mems_allowed or that we're in interrupt. It does not scan up the
+ * cpuset hierarchy for the nearest enclosing mem_exclusive cpuset.
+ * It never sleeps.
+ */
+
+int __cpuset_zone_allowed_hardwall(struct zone *z, gfp_t gfp_mask)
+{
+ int node; /* node that zone z is on */
+
+ if (in_interrupt() || (gfp_mask & __GFP_THISNODE))
+ return 1;
+ node = zone_to_nid(z);
+ if (node_isset(node, current->mems_allowed))
+ return 1;
+ /*
+ * Allow tasks that have access to memory reserves because they have
+ * been OOM killed to get memory anywhere.
+ */
+ if (unlikely(test_thread_flag(TIF_MEMDIE)))
+ return 1;
+ return 0;
+}
+
/**
- * cpuset_excl_nodes_overlap - Do we overlap @p's mem_exclusive ancestors?
- * @p: pointer to task_struct of some other task.
- *
- * Description: Return true if the nearest mem_exclusive ancestor
- * cpusets of tasks @p and current overlap. Used by oom killer to
- * determine if task @p's memory usage might impact the memory
- * available to the current task.
+ * cpuset_lock - lock out any changes to cpuset structures
+ *
+ * The out of memory (oom) code needs to mutex_lock cpusets
+ * from being changed while it scans the tasklist looking for a
+ * task in an overlapping cpuset. Expose callback_mutex via this
+ * cpuset_lock() routine, so the oom code can lock it, before
+ * locking the task list. The tasklist_lock is a spinlock, so
+ * must be taken inside callback_mutex.
+ */
+
+void cpuset_lock(void)
+{
+ mutex_lock(&callback_mutex);
+}
+
+/**
+ * cpuset_unlock - release lock on cpuset changes
*
- * Acquires callback_sem - not suitable for calling from a fast path.
- **/
+ * Undo the lock taken in a previous cpuset_lock() call.
+ */
-int cpuset_excl_nodes_overlap(const struct task_struct *p)
+void cpuset_unlock(void)
{
- const struct cpuset *cs1, *cs2; /* my and p's cpuset ancestors */
- int overlap = 0; /* do cpusets overlap? */
+ mutex_unlock(&callback_mutex);
+}
- down(&callback_sem);
+/**
+ * cpuset_mem_spread_node() - On which node to begin search for a page
+ *
+ * If a task is marked PF_SPREAD_PAGE or PF_SPREAD_SLAB (as for
+ * tasks in a cpuset with is_spread_page or is_spread_slab set),
+ * and if the memory allocation used cpuset_mem_spread_node()
+ * to determine on which node to start looking, as it will for
+ * certain page cache or slab cache pages such as used for file
+ * system buffers and inode caches, then instead of starting on the
+ * local node to look for a free page, rather spread the starting
+ * node around the tasks mems_allowed nodes.
+ *
+ * We don't have to worry about the returned node being offline
+ * because "it can't happen", and even if it did, it would be ok.
+ *
+ * The routines calling guarantee_online_mems() are careful to
+ * only set nodes in task->mems_allowed that are online. So it
+ * should not be possible for the following code to return an
+ * offline node. But if it did, that would be ok, as this routine
+ * is not returning the node where the allocation must be, only
+ * the node where the search should start. The zonelist passed to
+ * __alloc_pages() will include all nodes. If the slab allocator
+ * is passed an offline node, it will fall back to the local node.
+ * See kmem_cache_alloc_node().
+ */
- task_lock(current);
- if (current->flags & PF_EXITING) {
- task_unlock(current);
- goto done;
- }
- cs1 = nearest_exclusive_ancestor(current->cpuset);
- task_unlock(current);
+int cpuset_mem_spread_node(void)
+{
+ int node;
- task_lock((struct task_struct *)p);
- if (p->flags & PF_EXITING) {
- task_unlock((struct task_struct *)p);
- goto done;
- }
- cs2 = nearest_exclusive_ancestor(p->cpuset);
- task_unlock((struct task_struct *)p);
+ node = next_node(current->cpuset_mem_spread_rotor, current->mems_allowed);
+ if (node == MAX_NUMNODES)
+ node = first_node(current->mems_allowed);
+ current->cpuset_mem_spread_rotor = node;
+ return node;
+}
+EXPORT_SYMBOL_GPL(cpuset_mem_spread_node);
- overlap = nodes_intersects(cs1->mems_allowed, cs2->mems_allowed);
-done:
- up(&callback_sem);
+/**
+ * cpuset_mems_allowed_intersects - Does @tsk1's mems_allowed intersect @tsk2's?
+ * @tsk1: pointer to task_struct of some task.
+ * @tsk2: pointer to task_struct of some other task.
+ *
+ * Description: Return true if @tsk1's mems_allowed intersects the
+ * mems_allowed of @tsk2. Used by the OOM killer to determine if
+ * one of the task's memory usage might impact the memory available
+ * to the other.
+ **/
- return overlap;
+int cpuset_mems_allowed_intersects(const struct task_struct *tsk1,
+ const struct task_struct *tsk2)
+{
+ return nodes_intersects(tsk1->mems_allowed, tsk2->mems_allowed);
}
/*
void __cpuset_memory_pressure_bump(void)
{
- struct cpuset *cs;
-
task_lock(current);
- cs = current->cpuset;
- fmeter_markevent(&cs->fmeter);
+ fmeter_markevent(&task_cs(current)->fmeter);
task_unlock(current);
}
+#ifdef CONFIG_PROC_PID_CPUSET
/*
* proc_cpuset_show()
* - Print tasks cpuset path into seq_file.
* - Used for /proc/<pid>/cpuset.
* - No need to task_lock(tsk) on this tsk->cpuset reference, as it
* doesn't really matter if tsk->cpuset changes after we read it,
- * and we take manage_sem, keeping attach_task() from changing it
+ * and we take cgroup_mutex, keeping cpuset_attach() from changing it
* anyway.
*/
-
-static int proc_cpuset_show(struct seq_file *m, void *v)
+static int proc_cpuset_show(struct seq_file *m, void *unused_v)
{
- struct cpuset *cs;
+ struct pid *pid;
struct task_struct *tsk;
char *buf;
- int retval = 0;
+ struct cgroup_subsys_state *css;
+ int retval;
+ retval = -ENOMEM;
buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
if (!buf)
- return -ENOMEM;
-
- tsk = m->private;
- down(&manage_sem);
- cs = tsk->cpuset;
- if (!cs) {
- retval = -EINVAL;
goto out;
- }
- retval = cpuset_path(cs, buf, PAGE_SIZE);
+ retval = -ESRCH;
+ pid = m->private;
+ tsk = get_pid_task(pid, PIDTYPE_PID);
+ if (!tsk)
+ goto out_free;
+
+ retval = -EINVAL;
+ cgroup_lock();
+ css = task_subsys_state(tsk, cpuset_subsys_id);
+ retval = cgroup_path(css->cgroup, buf, PAGE_SIZE);
if (retval < 0)
- goto out;
+ goto out_unlock;
seq_puts(m, buf);
seq_putc(m, '\n');
-out:
- up(&manage_sem);
+out_unlock:
+ cgroup_unlock();
+ put_task_struct(tsk);
+out_free:
kfree(buf);
+out:
return retval;
}
static int cpuset_open(struct inode *inode, struct file *file)
{
- struct task_struct *tsk = PROC_I(inode)->task;
- return single_open(file, proc_cpuset_show, tsk);
+ struct pid *pid = PROC_I(inode)->pid;
+ return single_open(file, proc_cpuset_show, pid);
}
-struct file_operations proc_cpuset_operations = {
+const struct file_operations proc_cpuset_operations = {
.open = cpuset_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
+#endif /* CONFIG_PROC_PID_CPUSET */
/* Display task cpus_allowed, mems_allowed in /proc/<pid>/status file. */
-char *cpuset_task_status_allowed(struct task_struct *task, char *buffer)
-{
- buffer += sprintf(buffer, "Cpus_allowed:\t");
- buffer += cpumask_scnprintf(buffer, PAGE_SIZE, task->cpus_allowed);
- buffer += sprintf(buffer, "\n");
- buffer += sprintf(buffer, "Mems_allowed:\t");
- buffer += nodemask_scnprintf(buffer, PAGE_SIZE, task->mems_allowed);
- buffer += sprintf(buffer, "\n");
- return buffer;
+void cpuset_task_status_allowed(struct seq_file *m, struct task_struct *task)
+{
+ seq_printf(m, "Cpus_allowed:\t");
+ m->count += cpumask_scnprintf(m->buf + m->count, m->size - m->count,
+ task->cpus_allowed);
+ seq_printf(m, "\n");
+ seq_printf(m, "Mems_allowed:\t");
+ m->count += nodemask_scnprintf(m->buf + m->count, m->size - m->count,
+ task->mems_allowed);
+ seq_printf(m, "\n");
}
Code Review / linux-2.6.git / blobdiff