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Message-Id: <20180705181204.5529-1-chansen3@cisco.com>
Date: Thu, 5 Jul 2018 14:12:04 -0400
From: Christian Hansen <chansen3@...co.com>
To: linux-kernel@...r.kernel.org
Cc: akpm@...ux-foundation.org, Christian Hansen <chansen3@...co.com>
Subject: [PATCH] tools: modifying page-types to include shared map counts
Adding a new flag that will read kpagecount for each PFN
and print out the number of times the page is mapped along
with the flags in the listing view.
This information is useful in understanding and optimizing
memory usage. Identifying pages which are not shared allows
us to focus on adjusting the memory layout or access patterns
for the sole owning process. Knowing the number of processes
that share a page tells us how many other times we must make
the same adjustments or how many processes to potentially disable.
Truncated sample output:
voffset map-cnt offset len flags
561a3591e 1 15fe8 1 ___U_lA____Ma_b___________________________
561a3591f 1 2b103 1 ___U_lA____Ma_b___________________________
561a36ca4 1 2cc78 1 ___U_lA____Ma_b___________________________
7f588bb4e 14 2273c 1 __RU_lA____M______________________________
Signed-off-by: Christian Hansen <chansen3@...co.com>
---
Documentation/admin-guide/mm/pagemap.rst | 3 ++
tools/vm/page-types.c | 73 ++++++++++++++++++++++++++------
2 files changed, 62 insertions(+), 14 deletions(-)
diff --git a/Documentation/admin-guide/mm/pagemap.rst b/Documentation/admin-guide/mm/pagemap.rst
index 577af85..3f7bade 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 cce853d..7fe4797 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 @@ static void walk_file(const char *name, const struct stat *st)
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;
}
--
2.10.3.dirty
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