From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vasily Averin Subject: [PATCH v6 07/16] memcg: enable accounting for mnt_cache entries Date: Mon, 26 Jul 2021 22:00:48 +0300 Message-ID: <8d06c97c-451f-474b-026f-b898e2566daf@virtuozzo.com> References: <9bf9d9bd-03b1-2adb-17b4-5d59a86a9394@virtuozzo.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=virtuozzo.com; s=relay; h=Content-Type:MIME-Version:Date:Message-ID:Subject :From; bh=bgm9OS9KolAL5uXELhf+0mY9tqnepOoZ0HrSZvp8ULM=; b=fJg7jHp0nLOCKiZRvSW shjBPrvwZFDautLw7asTY58rHCktPPFXvYpeUmXDGP4Llrjo6vcM76twwpiQCwRt4LzY/MYnhlRTp IfRU9n/mBlGXktU/RJIw05ivHFKfA+terzsuXL2OkgTq2FebvFmw+g3OU0PHQOXFWgFdo1gcbrU=; In-Reply-To: Content-Language: en-US List-ID: Content-Type: text/plain; charset="us-ascii" To: Andrew Morton Cc: cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Michal Hocko , Shakeel Butt , Johannes Weiner , Vladimir Davydov , Roman Gushchin , Alexander Viro , linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org The kernel allocates ~400 bytes of 'strcut mount' for any new mount. Creating a new mount namespace clones most of the parent mounts, and this can be repeated many times. Additionally, each mount allocates up to PATH_MAX=4096 bytes for mnt->mnt_devname. It makes sense to account for these allocations to restrict the host's memory consumption from inside the memcg-limited container. Signed-off-by: Vasily Averin --- fs/namespace.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/fs/namespace.c b/fs/namespace.c index ab4174a..c6a74e5 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -203,7 +203,8 @@ static struct mount *alloc_vfsmnt(const char *name) goto out_free_cache; if (name) { - mnt->mnt_devname = kstrdup_const(name, GFP_KERNEL); + mnt->mnt_devname = kstrdup_const(name, + GFP_KERNEL_ACCOUNT); if (!mnt->mnt_devname) goto out_free_id; } @@ -4222,7 +4223,7 @@ void __init mnt_init(void) int err; mnt_cache = kmem_cache_create("mnt_cache", sizeof(struct mount), - 0, SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL); + 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT, NULL); mount_hashtable = alloc_large_system_hash("Mount-cache", sizeof(struct hlist_head), -- 1.8.3.1