kmemcg: account certain kmem allocations to memcg

Mark those kmem allocations that are known to be easily triggered from
userspace as __GFP_ACCOUNT/SLAB_ACCOUNT, which makes them accounted to
memcg.  For the list, see below:

 - threadinfo
 - task_struct
 - task_delay_info
 - pid
 - cred
 - mm_struct
 - vm_area_struct and vm_region (nommu)
 - anon_vma and anon_vma_chain
 - signal_struct
 - sighand_struct
 - fs_struct
 - files_struct
 - fdtable and fdtable->full_fds_bits
 - dentry and external_name
 - inode for all filesystems. This is the most tedious part, because
   most filesystems overwrite the alloc_inode method.

The list is far from complete, so feel free to add more objects.
Nevertheless, it should be close to "account everything" approach and
keep most workloads within bounds.  Malevolent users will be able to
breach the limit, but this was possible even with the former "account
everything" approach (simply because it did not account everything in
fact).

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Vladimir Davydov <vdavydov@virtuozzo.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Greg Thelen <gthelen@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 4 insertions, 2 deletions

diff --git a/fs/ecryptfs/main.c b/fs/ecryptfs/main.c
index 4f4d0474bee9..e25b6b06bacf 100644
--- a/fs/ecryptfs/main.c
+++ b/fs/ecryptfs/main.c
@@ -663,6 +663,7 @@ static struct ecryptfs_cache_info {
 	struct kmem_cache **cache;
 	const char *name;
 	size_t size;
+	unsigned long flags;
 	void (*ctor)(void *obj);
 } ecryptfs_cache_infos[] = {
 	{
@@ -684,6 +685,7 @@ static struct ecryptfs_cache_info {
 		.cache = &ecryptfs_inode_info_cache,
 		.name = "ecryptfs_inode_cache",
 		.size = sizeof(struct ecryptfs_inode_info),
+		.flags = SLAB_ACCOUNT,
 		.ctor = inode_info_init_once,
 	},
 	{
@@ -755,8 +757,8 @@ static int ecryptfs_init_kmem_caches(void)
 		struct ecryptfs_cache_info *info;
 
 		info = &ecryptfs_cache_infos[i];
-		*(info->cache) = kmem_cache_create(info->name, info->size,
-				0, SLAB_HWCACHE_ALIGN, info->ctor);
+		*(info->cache) = kmem_cache_create(info->name, info->size, 0,
+				SLAB_HWCACHE_ALIGN | info->flags, info->ctor);
 		if (!*(info->cache)) {
 			ecryptfs_free_kmem_caches();
 			ecryptfs_printk(KERN_WARNING, "%s: "