epoll-account-epitem-and-eppoll_entry-to-kmemcg.patch removed from -mm tree

The patch titled
Subject: epoll: account epitem and eppoll_entry to kmemcg
has been removed from the -mm tree. Its filename was
epoll-account-epitem-and-eppoll_entry-to-kmemcg.patch

This patch was dropped because it was merged into mainline or a subsystem tree

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From: Shakeel Butt <[email protected]>
Subject: epoll: account epitem and eppoll_entry to kmemcg

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.

---

 fs/eventpoll.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff -puN fs/eventpoll.c~epoll-account-epitem-and-eppoll_entry-to-kmemcg fs/eventpoll.c
@@ -2329,11 +2329,11 @@ 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;
 }

_

Patches currently in -mm which might be from [email protected] are