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>

3 files changed, 6 insertions, 4 deletions

diff --git a/mm/nommu.c b/mm/nommu.c
index 92be862c859b..fbf6f0f1d6c9 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -560,7 +560,7 @@ void __init mmap_init(void)
 
 	ret = percpu_counter_init(&vm_committed_as, 0, GFP_KERNEL);
 	VM_BUG_ON(ret);
-	vm_region_jar = KMEM_CACHE(vm_region, SLAB_PANIC);
+	vm_region_jar = KMEM_CACHE(vm_region, SLAB_PANIC|SLAB_ACCOUNT);
 }
 
 /*
diff --git a/mm/rmap.c b/mm/rmap.c
index b577fbb98d4b..3c3f1d21f075 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -428,8 +428,10 @@ static void anon_vma_ctor(void *data)
 void __init anon_vma_init(void)
 {
 	anon_vma_cachep = kmem_cache_create("anon_vma", sizeof(struct anon_vma),
-			0, SLAB_DESTROY_BY_RCU|SLAB_PANIC, anon_vma_ctor);
-	anon_vma_chain_cachep = KMEM_CACHE(anon_vma_chain, SLAB_PANIC);
+			0, SLAB_DESTROY_BY_RCU|SLAB_PANIC|SLAB_ACCOUNT,
+			anon_vma_ctor);
+	anon_vma_chain_cachep = KMEM_CACHE(anon_vma_chain,
+			SLAB_PANIC|SLAB_ACCOUNT);
 }
 
 /*
diff --git a/mm/shmem.c b/mm/shmem.c
index 5813b7fa85b6..9e60093aca3f 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -3064,7 +3064,7 @@ static int shmem_init_inodecache(void)
 {
 	shmem_inode_cachep = kmem_cache_create("shmem_inode_cache",
 				sizeof(struct shmem_inode_info),
-				0, SLAB_PANIC, shmem_init_inode);
+				0, SLAB_PANIC|SLAB_ACCOUNT, shmem_init_inode);
 	return 0;
 }