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-rw-r--r--Documentation/admin-guide/mm/pagemap.rst3
-rw-r--r--tools/vm/page-types.c73
2 files changed, 62 insertions, 14 deletions
diff --git a/Documentation/admin-guide/mm/pagemap.rst b/Documentation/admin-guide/mm/pagemap.rst
index 577af85beb41..3f7bade2c231 100644
--- a/Documentation/admin-guide/mm/pagemap.rst
+++ b/Documentation/admin-guide/mm/pagemap.rst
@@ -44,6 +44,9 @@ There are four components to pagemap:
* ``/proc/kpagecount``. This file contains a 64-bit count of the number of
times each page is mapped, indexed by PFN.
+The page-types tool in the tools/vm directory can be used to query the
+number of times a page is mapped.
+
* ``/proc/kpageflags``. This file contains a 64-bit set of flags for each
page, indexed by PFN.
diff --git a/tools/vm/page-types.c b/tools/vm/page-types.c
index cce853dca691..14ebd1695223 100644
--- a/tools/vm/page-types.c
+++ b/tools/vm/page-types.c
@@ -75,6 +75,7 @@
#define KPF_BYTES 8
#define PROC_KPAGEFLAGS "/proc/kpageflags"
+#define PROC_KPAGECOUNT "/proc/kpagecount"
#define PROC_KPAGECGROUP "/proc/kpagecgroup"
/* [32-] kernel hacking assistances */
@@ -173,6 +174,7 @@ static pid_t opt_pid; /* process to walk */
const char *opt_file; /* file or directory path */
static uint64_t opt_cgroup; /* cgroup inode */
static int opt_list_cgroup;/* list page cgroup */
+static int opt_list_mapcnt;/* list page map count */
static const char *opt_kpageflags;/* kpageflags file to parse */
#define MAX_ADDR_RANGES 1024
@@ -194,6 +196,7 @@ static int page_size;
static int pagemap_fd;
static int kpageflags_fd;
+static int kpagecount_fd = -1;
static int kpagecgroup_fd = -1;
static int opt_hwpoison;
@@ -298,6 +301,15 @@ static unsigned long kpagecgroup_read(uint64_t *buf,
return do_u64_read(kpagecgroup_fd, opt_kpageflags, buf, index, pages);
}
+static unsigned long kpagecount_read(uint64_t *buf,
+ unsigned long index,
+ unsigned long pages)
+{
+ return kpagecount_fd < 0 ? pages :
+ do_u64_read(kpagecount_fd, PROC_KPAGECOUNT,
+ buf, index, pages);
+}
+
static unsigned long pagemap_read(uint64_t *buf,
unsigned long index,
unsigned long pages)
@@ -370,16 +382,18 @@ static char *page_flag_longname(uint64_t flags)
*/
static void show_page_range(unsigned long voffset, unsigned long offset,
- unsigned long size, uint64_t flags, uint64_t cgroup)
+ unsigned long size, uint64_t flags,
+ uint64_t cgroup, uint64_t mapcnt)
{
static uint64_t flags0;
static uint64_t cgroup0;
+ static uint64_t mapcnt0;
static unsigned long voff;
static unsigned long index;
static unsigned long count;
- if (flags == flags0 && cgroup == cgroup0 && offset == index + count &&
- size && voffset == voff + count) {
+ if (flags == flags0 && cgroup == cgroup0 && mapcnt == mapcnt0 &&
+ offset == index + count && size && voffset == voff + count) {
count += size;
return;
}
@@ -391,12 +405,15 @@ static void show_page_range(unsigned long voffset, unsigned long offset,
printf("%lu\t", voff);
if (opt_list_cgroup)
printf("@%llu\t", (unsigned long long)cgroup0);
+ if (opt_list_mapcnt)
+ printf("%lu\t", mapcnt0);
printf("%lx\t%lx\t%s\n",
index, count, page_flag_name(flags0));
}
flags0 = flags;
- cgroup0= cgroup;
+ cgroup0 = cgroup;
+ mapcnt0 = mapcnt;
index = offset;
voff = voffset;
count = size;
@@ -404,11 +421,11 @@ static void show_page_range(unsigned long voffset, unsigned long offset,
static void flush_page_range(void)
{
- show_page_range(0, 0, 0, 0, 0);
+ show_page_range(0, 0, 0, 0, 0, 0);
}
static void show_page(unsigned long voffset, unsigned long offset,
- uint64_t flags, uint64_t cgroup)
+ uint64_t flags, uint64_t cgroup, uint64_t mapcnt)
{
if (opt_pid)
printf("%lx\t", voffset);
@@ -416,6 +433,9 @@ static void show_page(unsigned long voffset, unsigned long offset,
printf("%lu\t", voffset);
if (opt_list_cgroup)
printf("@%llu\t", (unsigned long long)cgroup);
+ if (opt_list_mapcnt)
+ printf("%lu\t", mapcnt);
+
printf("%lx\t%s\n", offset, page_flag_name(flags));
}
@@ -599,7 +619,8 @@ static size_t hash_slot(uint64_t flags)
}
static void add_page(unsigned long voffset, unsigned long offset,
- uint64_t flags, uint64_t cgroup, uint64_t pme)
+ uint64_t flags, uint64_t cgroup, uint64_t mapcnt,
+ uint64_t pme)
{
flags = kpageflags_flags(flags, pme);
@@ -615,9 +636,9 @@ static void add_page(unsigned long voffset, unsigned long offset,
unpoison_page(offset);
if (opt_list == 1)
- show_page_range(voffset, offset, 1, flags, cgroup);
+ show_page_range(voffset, offset, 1, flags, cgroup, mapcnt);
else if (opt_list == 2)
- show_page(voffset, offset, flags, cgroup);
+ show_page(voffset, offset, flags, cgroup, mapcnt);
nr_pages[hash_slot(flags)]++;
total_pages++;
@@ -631,6 +652,7 @@ static void walk_pfn(unsigned long voffset,
{
uint64_t buf[KPAGEFLAGS_BATCH];
uint64_t cgi[KPAGEFLAGS_BATCH];
+ uint64_t cnt[KPAGEFLAGS_BATCH];
unsigned long batch;
unsigned long pages;
unsigned long i;
@@ -654,8 +676,12 @@ static void walk_pfn(unsigned long voffset,
if (kpagecgroup_read(cgi, index, pages) != pages)
fatal("kpagecgroup returned fewer pages than expected");
+ if (kpagecount_read(cnt, index, batch) != pages)
+ fatal("kpagecount returned fewer pages than expected");
+
for (i = 0; i < pages; i++)
- add_page(voffset + i, index + i, buf[i], cgi[i], pme);
+ add_page(voffset + i, index + i,
+ buf[i], cgi[i], cnt[i], pme);
index += pages;
count -= pages;
@@ -673,9 +699,10 @@ static void walk_swap(unsigned long voffset, uint64_t pme)
return;
if (opt_list == 1)
- show_page_range(voffset, pagemap_swap_offset(pme), 1, flags, 0);
+ show_page_range(voffset, pagemap_swap_offset(pme),
+ 1, flags, 0, 0);
else if (opt_list == 2)
- show_page(voffset, pagemap_swap_offset(pme), flags, 0);
+ show_page(voffset, pagemap_swap_offset(pme), flags, 0, 0);
nr_pages[hash_slot(flags)]++;
total_pages++;
@@ -789,6 +816,7 @@ static void usage(void)
" -l|--list Show page details in ranges\n"
" -L|--list-each Show page details one by one\n"
" -C|--list-cgroup Show cgroup inode for pages\n"
+" -M|--list-mapcnt Show page map count\n"
" -N|--no-summary Don't show summary info\n"
" -X|--hwpoison hwpoison pages\n"
" -x|--unpoison unpoison pages\n"
@@ -925,6 +953,7 @@ static void walk_file(const char *name, const struct stat *st)
uint8_t vec[PAGEMAP_BATCH];
uint64_t buf[PAGEMAP_BATCH], flags;
uint64_t cgroup = 0;
+ uint64_t mapcnt = 0;
unsigned long nr_pages, pfn, i;
off_t off, end = st->st_size;
int fd;
@@ -984,13 +1013,15 @@ got_sigbus:
continue;
if (!kpagecgroup_read(&cgroup, pfn, 1))
fatal("kpagecgroup_read failed");
+ if (!kpagecount_read(&mapcnt, pfn, 1))
+ fatal("kpagecount_read failed");
if (first && opt_list) {
first = 0;
flush_page_range();
show_file(name, st);
}
add_page(off / page_size + i, pfn,
- flags, cgroup, buf[i]);
+ flags, cgroup, mapcnt, buf[i]);
}
}
@@ -1193,6 +1224,7 @@ static const struct option opts[] = {
{ "list" , 0, NULL, 'l' },
{ "list-each" , 0, NULL, 'L' },
{ "list-cgroup", 0, NULL, 'C' },
+ { "list-mapcnt", 0, NULL, 'M' },
{ "no-summary", 0, NULL, 'N' },
{ "hwpoison" , 0, NULL, 'X' },
{ "unpoison" , 0, NULL, 'x' },
@@ -1208,7 +1240,8 @@ int main(int argc, char *argv[])
page_size = getpagesize();
while ((c = getopt_long(argc, argv,
- "rp:f:a:b:d:c:ClLNXxF:h", opts, NULL)) != -1) {
+ "rp:f:a:b:d:c:ClLMNXxF:h",
+ opts, NULL)) != -1) {
switch (c) {
case 'r':
opt_raw = 1;
@@ -1240,6 +1273,9 @@ int main(int argc, char *argv[])
case 'L':
opt_list = 2;
break;
+ case 'M':
+ opt_list_mapcnt = 1;
+ break;
case 'N':
opt_no_summary = 1;
break;
@@ -1269,12 +1305,18 @@ int main(int argc, char *argv[])
if (opt_cgroup || opt_list_cgroup)
kpagecgroup_fd = checked_open(PROC_KPAGECGROUP, O_RDONLY);
+ if (opt_list && opt_list_mapcnt)
+ kpagecount_fd = checked_open(PROC_KPAGECOUNT, O_RDONLY);
+
if (opt_list && opt_pid)
printf("voffset\t");
if (opt_list && opt_file)
printf("foffset\t");
if (opt_list && opt_list_cgroup)
printf("cgroup\t");
+ if (opt_list && opt_list_mapcnt)
+ printf("map-cnt\t");
+
if (opt_list == 1)
printf("offset\tlen\tflags\n");
if (opt_list == 2)
@@ -1296,5 +1338,8 @@ int main(int argc, char *argv[])
show_summary();
+ if (opt_list_mapcnt)
+ close(kpagecount_fd);
+
return 0;
}
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.