[PATCH] mm/vmscan: add pgstall to memcg

[zhouchuyi <zhouchuyi@bytedance.com>]

Add pgstall to indicate the times of entering direct reclaim of memcg, use
the item of ALLOCSTALL_NORMAL in vmevents to save the data.

Signed-off-by: zhouchuyi <zhouchuyi@bytedance.com>
---


Hi，

I notice memcg uses some items to indicate the situation of direct reclaim in memory.stat，such as pgsteal and pgscan. 
I think there is no harm in adding another item to show the times of entering direct reclaim.

Thanks,
zhouchuyi


 Documentation/admin-guide/cgroup-v2.rst | 7 +++++--
 mm/memcontrol.c                         | 2 ++
 mm/vmscan.c                             | 5 ++++-
 3 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst
index 176298f2f..44c5b15bd 100644
--- a/Documentation/admin-guide/cgroup-v2.rst
+++ b/Documentation/admin-guide/cgroup-v2.rst
@@ -1447,8 +1447,11 @@ PAGE_SIZE multiple when read back.
 
 	  pgsteal (npn)
 		Amount of reclaimed pages
-
-	  pgactivate (npn)
+          
+          pgstall (npn)
+	  	Number of entering direct reclaim
+	  
+          pgactivate (npn)
 		Amount of pages moved to the active LRU list
 
 	  pgdeactivate (npn)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index abec50f31..f407084b2 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1505,6 +1505,8 @@ static char *memory_stat_format(struct mem_cgroup *memcg)
 	seq_buf_printf(&s, "pgscan %lu\n",
 		       memcg_events(memcg, PGSCAN_KSWAPD) +
 		       memcg_events(memcg, PGSCAN_DIRECT));
+	seq_buf_printf(&s, "pgstall %lu\n", 
+			   memcg_events(memcg, ALLOCSTALL_NORMAL));
 	seq_buf_printf(&s, "pgsteal %lu\n",
 		       memcg_events(memcg, PGSTEAL_KSWAPD) +
 		       memcg_events(memcg, PGSTEAL_DIRECT));
diff --git a/mm/vmscan.c b/mm/vmscan.c
index f7d9a683e..107cec59a 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -3532,7 +3532,10 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist,
 
 	if (!cgroup_reclaim(sc))
 		__count_zid_vm_events(ALLOCSTALL, sc->reclaim_idx, 1);
-
+	else {
+		count_memcg_events(sc->target_mem_cgroup, 
+					ALLOCSTALL_NORMAL, 1);
+	}
 	do {
 		vmpressure_prio(sc->gfp_mask, sc->target_mem_cgroup,
 				sc->priority);
-- 
2.20.1