[Devel] [PATCH RHEL7 COMMIT] ms/mm: memcontrol: retry reclaim for oom-disabled and __GFP_NOFAIL charges

[Konstantin Khorenko]

The commit is pushed to "branch-rh7-3.10.0-514.vz7.27.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-514.vz7.27.10
------>
commit 0ea4b7d076839a3390f37ca9dd34aeb5dd395dcb
Author: Johannes Weiner <hannes at cmpxchg.org>
Date:   Mon Jan 16 20:27:10 2017 +0400

    ms/mm: memcontrol: retry reclaim for oom-disabled and __GFP_NOFAIL charges
    
    There is no reason why oom-disabled and __GFP_NOFAIL charges should try
    to reclaim only once when every other charge tries several times before
    giving up.  Make them all retry the same number of times.
    
    Signed-off-by: Johannes Weiner <hannes at cmpxchg.org>
    Acked-by: Michal Hocko <mhocko at suse.cz>
    Cc: Hugh Dickins <hughd at google.com>
    Cc: Tejun Heo <tj at kernel.org>
    Cc: Vladimir Davydov <vdavydov at parallels.com>
    Signed-off-by: Andrew Morton <akpm at linux-foundation.org>
    Signed-off-by: Linus Torvalds <torvalds at linux-foundation.org>
    
    https://jira.sw.ru/browse/PSBM-51558
    (cherry picked from commit 9b1306192d335759a6cf2f3b404c49e811e5f953)
    Signed-off-by: Andrey Ryabinin <aryabinin at virtuozzo.com>
---
 mm/memcontrol.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 3608d80..a53d55d 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2759,7 +2759,7 @@ static int mem_cgroup_try_charge(struct mem_cgroup *memcg,
 				 bool oom)
 {
 	unsigned int batch = max(CHARGE_BATCH, nr_pages);
-	int nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES;
+	int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
 	struct mem_cgroup *mem_over_limit;
 	struct page_counter *counter;
 	unsigned long nr_reclaimed;
@@ -2829,6 +2829,9 @@ retry:
 	if (mem_cgroup_wait_acct_move(mem_over_limit))
 		goto retry;
 
+	if (nr_retries--)
+		goto retry;
+
 	if (gfp_mask & __GFP_NOFAIL)
 		goto bypass;
 
@@ -2838,9 +2841,6 @@ retry:
 	if (!oom)
 		goto nomem;
 
-	if (nr_oom_retries--)
-		goto retry;
-
 	mem_cgroup_oom(mem_over_limit, gfp_mask, get_order(batch));
 	mem_cgroup_inc_failcnt(mem_over_limit, gfp_mask, nr_pages);