The commit is pushed to "branch-rh8-4.18.0-240.1.1.vz8.5.x-ovz" and will appear
at https://src.openvz.org/scm/ovz/vzkernel.git
after rh8-4.18.0-240.1.1.vz8.5.41
------>
commit f79da6e8f0f06cf17a4bf10bd160feebbb526c74
Author: Andrey Ryabinin <[email protected]>
Date: Fri Jun 11 20:22:47 2021 +0300
mm, memcg, oom_gurantee: change memcg oom overdraft formula
Currently our oom killer kill tasks from cgroup with max overdraft.
Overdraft formula looks like this "usage/(gurantee + 1)". Which makes
all cgroups without gurantee (default) to be a first candidates for oom
kill since "usage_cgrp1"/"hundreds of megabytes" always < usage_cgrp2/1.
Change overdraft formula to simple "usage > guarantee ? usage - guarantee :
0".
Unrelated note: oom_guarantee is 0 by default and not inherited from parent
cgroup. Not going to change it since currently ther is no necessity for it.
Also this would require from userspace to make sure that oom_guarantee set
for all sub cgroups of cgroups like machine.slice wich has unreacheable high
oom_guarantee and we don't want this high guarantee on sub groups.
https://pmc.acronis.com/browse/VSTOR-22575
Signed-off-by: Andrey Ryabinin <[email protected]>
Reviewed-by: Konstantin Khorenko <[email protected]>
https://jira.sw.ru/browse/PSBM-127846
(cherry-picked from vz7 commit 0996bb7c7837 ("mm, memcg, oom_gurantee:
change memcg oom overdraft formula"))
Fixes: 02ccefe3c24f ("memcg: add oom_guarantee")
Signed-off-by: Pavel Tikhomirov <[email protected]>
---
mm/memcontrol.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 18f90e5467bb..74bad9ff98b9 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1364,7 +1364,7 @@ unsigned long mem_cgroup_overdraft(struct mem_cgroup
*memcg)
guarantee = READ_ONCE(memcg->oom_guarantee);
usage = page_counter_read(&memcg->memsw);
- return div64_u64(1000 * usage, guarantee + 1);
+ return usage > guarantee ? (usage - guarantee) : 0;
}
bool mem_cgroup_dcache_is_low(struct mem_cgroup *memcg, int
vfs_cache_min_ratio)
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