[Devel] [PATCH rh7 1/2] mm: memcontrol: add swapin/out stats

[Vladimir Davydov]

This patch adds pswpin and pswpout fields to memory.stat file. These
fields show the number of pages swapped in and out respectively for the
given memory cgroup. We assume a page was swapped in/out even if there
were no actual io (frontswap).

https://jira.sw.ru/browse/PSBM-46104

Signed-off-by: Vladimir Davydov <vdavydov at virtuozzo.com>
---
 mm/memcontrol.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index f617423a3ade..29716f465ffb 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -112,6 +112,8 @@ static const char * const mem_cgroup_stat_names[] = {
 enum mem_cgroup_events_index {
 	MEM_CGROUP_EVENTS_PGPGIN,	/* # of pages paged in */
 	MEM_CGROUP_EVENTS_PGPGOUT,	/* # of pages paged out */
+	MEM_CGROUP_EVENTS_PSWPIN,	/* # of pages swapped in */
+	MEM_CGROUP_EVENTS_PSWPOUT,	/* # of pages swapped out */
 	MEM_CGROUP_EVENTS_PGFAULT,	/* # of page-faults */
 	MEM_CGROUP_EVENTS_PGMAJFAULT,	/* # of major page-faults */
 	MEM_CGROUP_EVENTS_NSTATS,
@@ -120,6 +122,8 @@ enum mem_cgroup_events_index {
 static const char * const mem_cgroup_events_names[] = {
 	"pgpgin",
 	"pgpgout",
+	"pswpin",
+	"pswpout",
 	"pgfault",
 	"pgmajfault",
 };
@@ -3945,6 +3949,8 @@ __mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *memcg,
 		swp_entry_t ent = {.val = page_private(page)};
 		mem_cgroup_uncharge_swap(ent);
 	}
+
+	this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PSWPIN]);
 }
 
 void mem_cgroup_commit_charge_swapin(struct page *page,
@@ -4234,6 +4240,9 @@ mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout)
 	 */
 	if (do_swap_account && swapout && memcg)
 		swap_cgroup_record(ent, css_id(&memcg->css));
+
+	if (swapout && memcg)
+		this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PSWPOUT]);
 }
 #endif
 
-- 
2.1.4