From f3f7c09355784b02e49853dd1403d0e2d4f991c6 Mon Sep 17 00:00:00 2001 From: Shakeel Butt Date: Wed, 15 Nov 2017 17:35:44 -0800 Subject: [PATCH] fs, mm: account filp cache to kmemcg The allocations from filp cache can be directly triggered by userspace applications. A buggy application can consume a significant amount of unaccounted system memory. Though we have not noticed such buggy applications in our production but upon close inspection, we found that a lot of machines spend very significant amount of memory on these caches. One way to limit allocations from filp cache is to set system level limit of maximum number of open files. However this limit is shared between different users on the system and one user can hog this resource. To cater that, we can charge filp to kmemcg and set the maximum limit very high and let the memory limit of each user limit the number of files they can open and indirectly limiting their allocations from filp cache. One side effect of this change is that it will allow _sysctl() to return ENOMEM and the man page of _sysctl() does not specify that. However the man page also discourages to use _sysctl() at all. Link: http://lkml.kernel.org/r/20171011190359.34926-1-shakeelb@google.com Signed-off-by: Shakeel Butt Cc: Alexander Viro Cc: Vladimir Davydov Cc: Michal Hocko Cc: Greg Thelen Cc: Johannes Weiner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/file_table.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/file_table.c b/fs/file_table.c index 49e1f2f1a4cb..2dc9f38bd195 100644 --- a/fs/file_table.c +++ b/fs/file_table.c @@ -312,7 +312,7 @@ void put_filp(struct file *file) void __init files_init(void) { filp_cachep = kmem_cache_create("filp", sizeof(struct file), 0, - SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL); + SLAB_HWCACHE_ALIGN | SLAB_PANIC | SLAB_ACCOUNT, NULL); percpu_counter_init(&nr_files, 0, GFP_KERNEL); } -- 2.30.2