Cgroups currently don't report how much shmem they use, which can be
useful data to have, in particular since shmem is included in the
cache/file item while being reclaimed like anonymous memory.
Add a counter to track shmem pages during charging and uncharging.
Reported-by: Chris Down <cdown@xxxxxx>
Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>
---
Documentation/cgroup-v2.txt | 5 +++++
include/linux/memcontrol.h | 1 +
mm/memcontrol.c | 28 ++++++++++++++++++++--------
3 files changed, 26 insertions(+), 8 deletions(-)
diff --git a/Documentation/cgroup-v2.txt b/Documentation/cgroup-v2.txt
index 4cc07ce3b8dd..d99389ce7b01 100644
--- a/Documentation/cgroup-v2.txt
+++ b/Documentation/cgroup-v2.txt
@@ -867,6 +867,11 @@ PAGE_SIZE multiple when read back.
Amount of memory used in network transmission buffers
+ shmem
+
+ Amount of cached filesystem data that is swap-backed,
+ such as tmpfs, shm segments, shared anonymous mmap()s
+
file_mapped
Amount of cached filesystem data mapped with mmap()
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 61d20c17f3b7..47bdf727d1ad 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -46,6 +46,7 @@ enum mem_cgroup_stat_index {
MEM_CGROUP_STAT_CACHE, /* # of pages charged as cache */
MEM_CGROUP_STAT_RSS, /* # of pages charged as anon rss */
MEM_CGROUP_STAT_RSS_HUGE, /* # of pages charged as anon huge */
+ MEM_CGROUP_STAT_SHMEM, /* # of pages charged as shmem */
MEM_CGROUP_STAT_FILE_MAPPED, /* # of pages charged as file rss */
MEM_CGROUP_STAT_DIRTY, /* # of dirty pages in page cache */
MEM_CGROUP_STAT_WRITEBACK, /* # of pages under writeback */
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 9c9cde768d40..49409f5c0238 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -102,6 +102,7 @@ static const char * const mem_cgroup_stat_names[] = {
"cache",
"rss",
"rss_huge",
+ "shmem",
"mapped_file",
"dirty",
"writeback",
@@ -601,9 +602,13 @@ static void mem_cgroup_charge_statistics(struct mem_cgroup *memcg,
if (PageAnon(page))
__this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_RSS],
nr_pages);
- else
+ else {
__this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_CACHE],
nr_pages);
+ if (PageSwapBacked(page))
+ __this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_SHMEM],
+ nr_pages);
+ }
if (compound) {
VM_BUG_ON_PAGE(!PageTransHuge(page), page);
@@ -5200,6 +5205,8 @@ static int memory_stat_show(struct seq_file *m, void *v)
seq_printf(m, "sock %llu\n",
(u64)stat[MEMCG_SOCK] * PAGE_SIZE);
+ seq_printf(m, "shmem %llu\n",
+ (u64)stat[MEM_CGROUP_STAT_SHMEM] * PAGE_SIZE);
seq_printf(m, "file_mapped %llu\n",
(u64)stat[MEM_CGROUP_STAT_FILE_MAPPED] * PAGE_SIZE);
seq_printf(m, "file_dirty %llu\n",
@@ -5468,8 +5475,8 @@ void mem_cgroup_cancel_charge(struct page *page, struct mem_cgroup *memcg,
static void uncharge_batch(struct mem_cgroup *memcg, unsigned long pgpgout,
unsigned long nr_anon, unsigned long nr_file,
- unsigned long nr_huge, unsigned long nr_kmem,
- struct page *dummy_page)
+ unsigned long nr_kmem, unsigned long nr_huge,
+ unsigned long nr_shmem, struct page *dummy_page)
{
unsigned long nr_pages = nr_anon + nr_file + nr_kmem;
unsigned long flags;
@@ -5487,6 +5494,7 @@ static void uncharge_batch(struct mem_cgroup *memcg, unsigned long pgpgout,
__this_cpu_sub(memcg->stat->count[MEM_CGROUP_STAT_RSS], nr_anon);
__this_cpu_sub(memcg->stat->count[MEM_CGROUP_STAT_CACHE], nr_file);
__this_cpu_sub(memcg->stat->count[MEM_CGROUP_STAT_RSS_HUGE], nr_huge);
+ __this_cpu_sub(memcg->stat->count[MEM_CGROUP_STAT_SHMEM], nr_shmem);
__this_cpu_add(memcg->stat->events[MEM_CGROUP_EVENTS_PGPGOUT], pgpgout);
__this_cpu_add(memcg->stat->nr_page_events, nr_pages);
memcg_check_events(memcg, dummy_page);
@@ -5499,6 +5507,7 @@ static void uncharge_batch(struct mem_cgroup *memcg, unsigned long pgpgout,
static void uncharge_list(struct list_head *page_list)
{
struct mem_cgroup *memcg = NULL;
+ unsigned long nr_shmem = 0;
unsigned long nr_anon = 0;
unsigned long nr_file = 0;
unsigned long nr_huge = 0;
@@ -5531,9 +5540,9 @@ static void uncharge_list(struct list_head *page_list)
if (memcg != page->mem_cgroup) {
if (memcg) {
uncharge_batch(memcg, pgpgout, nr_anon, nr_file,
- nr_huge, nr_kmem, page);
- pgpgout = nr_anon = nr_file =
- nr_huge = nr_kmem = 0;
+ nr_kmem, nr_huge, nr_shmem, page);
+ pgpgout = nr_anon = nr_file = nr_kmem = 0;
+ nr_huge = nr_shmem = 0;
}
memcg = page->mem_cgroup;
}
@@ -5547,8 +5556,11 @@ static void uncharge_list(struct list_head *page_list)
}
if (PageAnon(page))
nr_anon += nr_pages;
- else
+ else {
nr_file += nr_pages;
+ if (PageSwapBacked(page))
+ nr_shmem += nr_pages;
+ }
pgpgout++;
} else {
nr_kmem += 1 << compound_order(page);
@@ -5560,7 +5572,7 @@ static void uncharge_list(struct list_head *page_list)
if (memcg)
uncharge_batch(memcg, pgpgout, nr_anon, nr_file,
- nr_huge, nr_kmem, page);
+ nr_kmem, nr_huge, nr_shmem, page);
}
/**
--
2.11.1
--
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