page-types: add feature for walking process address space
Wu Fengguang [Wed, 23 Sep 2009 22:56:16 +0000 (15:56 -0700)]
Introduce "-p|--pid <pid>" for walking the process address space.  The
default action is to walk raw memory PFNs.

Both the virtual address and physical address of each present pages will
be listed:

# ./tools/vm/page-types -lp $$ | head -3
voffset offset  len     flags
400     11bebe  1       __RU_lA____M______________________
402     11bebc  1       __RU_lA____M______________________

Note that voffset/offset/len are now showed as hex numbers.

[akpm@linux-foundation.org: coding-style fixes]
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Documentation/vm/page-types.c

index 3eda8ea..fa1a30d 100644 (file)
@@ -5,6 +5,7 @@
  * Copyright (C) 2009 Wu Fengguang <fengguang.wu@intel.com>
  */
 
+#define _LARGEFILE64_SOURCE
 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
 #include <string.h>
 #include <getopt.h>
 #include <limits.h>
+#include <assert.h>
 #include <sys/types.h>
 #include <sys/errno.h>
 #include <sys/fcntl.h>
 
 
 /*
+ * pagemap kernel ABI bits
+ */
+
+#define PM_ENTRY_BYTES      sizeof(uint64_t)
+#define PM_STATUS_BITS      3
+#define PM_STATUS_OFFSET    (64 - PM_STATUS_BITS)
+#define PM_STATUS_MASK      (((1LL << PM_STATUS_BITS) - 1) << PM_STATUS_OFFSET)
+#define PM_STATUS(nr)       (((nr) << PM_STATUS_OFFSET) & PM_STATUS_MASK)
+#define PM_PSHIFT_BITS      6
+#define PM_PSHIFT_OFFSET    (PM_STATUS_OFFSET - PM_PSHIFT_BITS)
+#define PM_PSHIFT_MASK      (((1LL << PM_PSHIFT_BITS) - 1) << PM_PSHIFT_OFFSET)
+#define PM_PSHIFT(x)        (((u64) (x) << PM_PSHIFT_OFFSET) & PM_PSHIFT_MASK)
+#define PM_PFRAME_MASK      ((1LL << PM_PSHIFT_OFFSET) - 1)
+#define PM_PFRAME(x)        ((x) & PM_PFRAME_MASK)
+
+#define PM_PRESENT          PM_STATUS(4LL)
+#define PM_SWAP             PM_STATUS(2LL)
+
+
+/*
  * kernel page flags
  */
 
@@ -126,6 +148,14 @@ static int         nr_addr_ranges;
 static unsigned long   opt_offset[MAX_ADDR_RANGES];
 static unsigned long   opt_size[MAX_ADDR_RANGES];
 
+#define MAX_VMAS       10240
+static int             nr_vmas;
+static unsigned long   pg_start[MAX_VMAS];
+static unsigned long   pg_end[MAX_VMAS];
+static unsigned long   voffset;
+
+static int             pagemap_fd;
+
 #define MAX_BIT_FILTERS        64
 static int             nr_bit_filters;
 static uint64_t                opt_mask[MAX_BIT_FILTERS];
@@ -135,7 +165,6 @@ static int          page_size;
 
 #define PAGES_BATCH    (64 << 10)      /* 64k pages */
 static int             kpageflags_fd;
-static uint64_t                kpageflags_buf[KPF_BYTES * PAGES_BATCH];
 
 #define HASH_SHIFT     13
 #define HASH_SIZE      (1 << HASH_SHIFT)
@@ -158,6 +187,11 @@ static uint64_t    page_flags[HASH_SIZE];
        type __min2 = (y);                      \
        __min1 < __min2 ? __min1 : __min2; })
 
+#define max_t(type, x, y) ({                   \
+       type __max1 = (x);                      \
+       type __max2 = (y);                      \
+       __max1 > __max2 ? __max1 : __max2; })
+
 static unsigned long pages2mb(unsigned long pages)
 {
        return (pages * page_size) >> 20;
@@ -224,26 +258,34 @@ static char *page_flag_longname(uint64_t flags)
 static void show_page_range(unsigned long offset, uint64_t flags)
 {
        static uint64_t      flags0;
+       static unsigned long voff;
        static unsigned long index;
        static unsigned long count;
 
-       if (flags == flags0 && offset == index + count) {
+       if (flags == flags0 && offset == index + count &&
+           (!opt_pid || voffset == voff + count)) {
                count++;
                return;
        }
 
-       if (count)
-               printf("%lu\t%lu\t%s\n",
+       if (count) {
+               if (opt_pid)
+                       printf("%lx\t", voff);
+               printf("%lx\t%lx\t%s\n",
                                index, count, page_flag_name(flags0));
+       }
 
        flags0 = flags;
        index  = offset;
+       voff   = voffset;
        count  = 1;
 }
 
 static void show_page(unsigned long offset, uint64_t flags)
 {
-       printf("%lu\t%s\n", offset, page_flag_name(flags));
+       if (opt_pid)
+               printf("%lx\t", voffset);
+       printf("%lx\t%s\n", offset, page_flag_name(flags));
 }
 
 static void show_summary(void)
@@ -383,6 +425,8 @@ static void walk_pfn(unsigned long index, unsigned long count)
        lseek(kpageflags_fd, index * KPF_BYTES, SEEK_SET);
 
        while (count) {
+               uint64_t kpageflags_buf[KPF_BYTES * PAGES_BATCH];
+
                batch = min_t(unsigned long, count, PAGES_BATCH);
                n = read(kpageflags_fd, kpageflags_buf, batch * KPF_BYTES);
                if (n == 0)
@@ -404,6 +448,81 @@ static void walk_pfn(unsigned long index, unsigned long count)
        }
 }
 
+
+#define PAGEMAP_BATCH  4096
+static unsigned long task_pfn(unsigned long pgoff)
+{
+       static uint64_t buf[PAGEMAP_BATCH];
+       static unsigned long start;
+       static long count;
+       uint64_t pfn;
+
+       if (pgoff < start || pgoff >= start + count) {
+               if (lseek64(pagemap_fd,
+                           (uint64_t)pgoff * PM_ENTRY_BYTES,
+                           SEEK_SET) < 0) {
+                       perror("pagemap seek");
+                       exit(EXIT_FAILURE);
+               }
+               count = read(pagemap_fd, buf, sizeof(buf));
+               if (count == 0)
+                       return 0;
+               if (count < 0) {
+                       perror("pagemap read");
+                       exit(EXIT_FAILURE);
+               }
+               if (count % PM_ENTRY_BYTES) {
+                       fatal("pagemap read not aligned.\n");
+                       exit(EXIT_FAILURE);
+               }
+               count /= PM_ENTRY_BYTES;
+               start = pgoff;
+       }
+
+       pfn = buf[pgoff - start];
+       if (pfn & PM_PRESENT)
+               pfn = PM_PFRAME(pfn);
+       else
+               pfn = 0;
+
+       return pfn;
+}
+
+static void walk_task(unsigned long index, unsigned long count)
+{
+       int i = 0;
+       const unsigned long end = index + count;
+
+       while (index < end) {
+
+               while (pg_end[i] <= index)
+                       if (++i >= nr_vmas)
+                               return;
+               if (pg_start[i] >= end)
+                       return;
+
+               voffset = max_t(unsigned long, pg_start[i], index);
+               index   = min_t(unsigned long, pg_end[i], end);
+
+               assert(voffset < index);
+               for (; voffset < index; voffset++) {
+                       unsigned long pfn = task_pfn(voffset);
+                       if (pfn)
+                               walk_pfn(pfn, 1);
+               }
+       }
+}
+
+static void add_addr_range(unsigned long offset, unsigned long size)
+{
+       if (nr_addr_ranges >= MAX_ADDR_RANGES)
+               fatal("too many addr ranges\n");
+
+       opt_offset[nr_addr_ranges] = offset;
+       opt_size[nr_addr_ranges] = min_t(unsigned long, size, ULONG_MAX-offset);
+       nr_addr_ranges++;
+}
+
 static void walk_addr_ranges(void)
 {
        int i;
@@ -415,10 +534,13 @@ static void walk_addr_ranges(void)
        }
 
        if (!nr_addr_ranges)
-               walk_pfn(0, ULONG_MAX);
+               add_addr_range(0, ULONG_MAX);
 
        for (i = 0; i < nr_addr_ranges; i++)
-               walk_pfn(opt_offset[i], opt_size[i]);
+               if (!opt_pid)
+                       walk_pfn(opt_offset[i], opt_size[i]);
+               else
+                       walk_task(opt_offset[i], opt_size[i]);
 
        close(kpageflags_fd);
 }
@@ -446,8 +568,8 @@ static void usage(void)
 "            -r|--raw                  Raw mode, for kernel developers\n"
 "            -a|--addr    addr-spec    Walk a range of pages\n"
 "            -b|--bits    bits-spec    Walk pages with specified bits\n"
-#if 0 /* planned features */
 "            -p|--pid     pid          Walk process address space\n"
+#if 0 /* planned features */
 "            -f|--file    filename     Walk file address space\n"
 #endif
 "            -l|--list                 Show page details in ranges\n"
@@ -459,7 +581,7 @@ static void usage(void)
 "            N+M                       pages range from N to N+M-1\n"
 "            N,M                       pages range from N to M-1\n"
 "            N,                        pages range from N to end\n"
-"            ,M                        pages range from 0 to M\n"
+"            ,M                        pages range from 0 to M-1\n"
 "bits-spec:\n"
 "            bit1,bit2                 (flags & (bit1|bit2)) != 0\n"
 "            bit1,bit2=bit1            (flags & (bit1|bit2)) == bit1\n"
@@ -496,21 +618,57 @@ static unsigned long long parse_number(const char *str)
 
 static void parse_pid(const char *str)
 {
+       FILE *file;
+       char buf[5000];
+
        opt_pid = parse_number(str);
-}
 
-static void parse_file(const char *name)
-{
+       sprintf(buf, "/proc/%d/pagemap", opt_pid);
+       pagemap_fd = open(buf, O_RDONLY);
+       if (pagemap_fd < 0) {
+               perror(buf);
+               exit(EXIT_FAILURE);
+       }
+
+       sprintf(buf, "/proc/%d/maps", opt_pid);
+       file = fopen(buf, "r");
+       if (!file) {
+               perror(buf);
+               exit(EXIT_FAILURE);
+       }
+
+       while (fgets(buf, sizeof(buf), file) != NULL) {
+               unsigned long vm_start;
+               unsigned long vm_end;
+               unsigned long long pgoff;
+               int major, minor;
+               char r, w, x, s;
+               unsigned long ino;
+               int n;
+
+               n = sscanf(buf, "%lx-%lx %c%c%c%c %llx %x:%x %lu",
+                          &vm_start,
+                          &vm_end,
+                          &r, &w, &x, &s,
+                          &pgoff,
+                          &major, &minor,
+                          &ino);
+               if (n < 10) {
+                       fprintf(stderr, "unexpected line: %s\n", buf);
+                       continue;
+               }
+               pg_start[nr_vmas] = vm_start / page_size;
+               pg_end[nr_vmas] = vm_end / page_size;
+               if (++nr_vmas >= MAX_VMAS) {
+                       fprintf(stderr, "too many VMAs\n");
+                       break;
+               }
+       }
+       fclose(file);
 }
 
-static void add_addr_range(unsigned long offset, unsigned long size)
+static void parse_file(const char *name)
 {
-       if (nr_addr_ranges >= MAX_ADDR_RANGES)
-               fatal("too much addr ranges\n");
-
-       opt_offset[nr_addr_ranges] = offset;
-       opt_size[nr_addr_ranges] = size;
-       nr_addr_ranges++;
 }
 
 static void parse_addr_range(const char *optarg)
@@ -676,8 +834,10 @@ int main(int argc, char *argv[])
                }
        }
 
+       if (opt_list && opt_pid)
+               printf("voffset\t");
        if (opt_list == 1)
-               printf("offset\tcount\tflags\n");
+               printf("offset\tlen\tflags\n");
        if (opt_list == 2)
                printf("offset\tflags\n");