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page-types: add feature for walking process address space
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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>
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Wu Fengguang authored and Linus Torvalds committed Sep 24, 2009
1 parent ba36c44 commit 0b4b2ad
Showing 1 changed file with 180 additions and 20 deletions.
200 changes: 180 additions & 20 deletions Documentation/vm/page-types.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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>
Expand All @@ -13,11 +14,32 @@
#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
*/
Expand Down Expand Up @@ -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];
Expand All @@ -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)
Expand All @@ -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;
Expand Down Expand Up @@ -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)
Expand Down Expand Up @@ -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)
Expand All @@ -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;
Expand All @@ -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);
}
Expand Down Expand Up @@ -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"
Expand All @@ -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"
Expand Down Expand Up @@ -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)
Expand Down Expand Up @@ -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");

Expand Down

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