From: Shakeel Butt <[email protected]> A userspace application can directly trigger the allocations from eventpoll_epi and eventpoll_pwq slabs. A buggy or malicious application can consume a significant amount of system memory by triggering such allocations. Indeed we have seen in production where a buggy application was leaking the epoll references and causing a burst of eventpoll_epi and eventpoll_pwq slab allocations. This patch opt-in the charging of eventpoll_epi and eventpoll_pwq slabs.
There is a per-user limit (~4% of total memory if no highmem) on these caches. I think it is too generous particularly in the scenario where jobs of multiple users are running on the system and the administrator is reducing cost by overcomitting the memory. This is unaccounted kernel memory and will not be considered by the oom-killer. I think by accounting it to kmemcg, for systems with kmem accounting enabled, we can provide better isolation between jobs of different users. Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Shakeel Butt <[email protected]> Acked-by: Michal Hocko <[email protected]> Cc: Alexander Viro <[email protected]> Cc: Vladimir Davydov <[email protected]> Cc: Johannes Weiner <[email protected]> Cc: Greg Thelen <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]> (cherry-picked upstream commit 2ae928a9441a3b5f13952e1e8a97d03cb23ea603) https://jira.sw.ru/browse/PSBM-108292 Signed-off-by: Vasily Averin <[email protected]> --- fs/eventpoll.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/eventpoll.c b/fs/eventpoll.c index 760459c510ec..b72b32c0d78f 100644 --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -2226,11 +2226,11 @@ static int __init eventpoll_init(void) /* Allocates slab cache used to allocate "struct epitem" items */ epi_cache = kmem_cache_create("eventpoll_epi", sizeof(struct epitem), - 0, SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL); + 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT, NULL); /* Allocates slab cache used to allocate "struct eppoll_entry" */ pwq_cache = kmem_cache_create("eventpoll_pwq", - sizeof(struct eppoll_entry), 0, SLAB_PANIC, NULL); + sizeof(struct eppoll_entry), 0, SLAB_PANIC|SLAB_ACCOUNT, NULL); return 0; } -- 2.17.1 _______________________________________________ Devel mailing list [email protected] https://lists.openvz.org/mailman/listinfo/devel
