diff mbox series

[mm,v2,4/9] memcg: enable accounting for struct simple_xattr

Message ID b69d2389-3a1f-d0bb-6a14-83473fe2d815@openvz.org (mailing list archive)
State New
Headers show
Series memcg: accounting for objects allocated by mkdir cgroup | expand

Commit Message

Vasily Averin May 21, 2022, 4:38 p.m. UTC 
kernfs nodes are quite small kernel objects, however there are few
scenarios where it consumes significant piece of all allocated memory:

1) creating a new netdevice allocates ~50Kb of memory, where ~10Kb
   was allocated for 80+ kernfs nodes.

2) cgroupv2 mkdir allocates ~60Kb of memory, ~10Kb of them are kernfs
   structures.

3) Shakeel Butt reports that Google has workloads which create 100s
   of subcontainers and they have observed high system overhead
   without memcg accounting of kernfs.

Usually new kernfs node creates few other objects:

Allocs  Alloc   Allocation
number  size
--------------------------------------------
1   +  128      (__kernfs_new_node+0x4d)        kernfs node
1   +   88      (__kernfs_iattrs+0x57)          kernfs iattrs
1   +   96      (simple_xattr_alloc+0x28)       simple_xattr
1       32      (simple_xattr_set+0x59)
1       8       (__kernfs_new_node+0x30)

'+' -- to be accounted

This patch enables accounting for struct simple_xattr. Size of this
structure depends on userspace and can grow over 4Kb.

Signed-off-by: Vasily Averin <vvs@openvz.org>
Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>
Reviewed-by: Michal Koutný <mkoutny@suse.com>
Acked-by: Shakeel Butt <shakeelb@google.com>
---
 fs/xattr.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Muchun Song May 22, 2022, 6:38 a.m. UTC | #1 
On Sat, May 21, 2022 at 07:38:11PM +0300, Vasily Averin wrote:
> kernfs nodes are quite small kernel objects, however there are few
> scenarios where it consumes significant piece of all allocated memory:
> 
> 1) creating a new netdevice allocates ~50Kb of memory, where ~10Kb
>    was allocated for 80+ kernfs nodes.
> 
> 2) cgroupv2 mkdir allocates ~60Kb of memory, ~10Kb of them are kernfs
>    structures.
> 
> 3) Shakeel Butt reports that Google has workloads which create 100s
>    of subcontainers and they have observed high system overhead
>    without memcg accounting of kernfs.
> 
> Usually new kernfs node creates few other objects:
> 
> Allocs  Alloc   Allocation
> number  size
> --------------------------------------------
> 1   +  128      (__kernfs_new_node+0x4d)        kernfs node
> 1   +   88      (__kernfs_iattrs+0x57)          kernfs iattrs
> 1   +   96      (simple_xattr_alloc+0x28)       simple_xattr
> 1       32      (simple_xattr_set+0x59)
> 1       8       (__kernfs_new_node+0x30)
> 
> '+' -- to be accounted
> 
> This patch enables accounting for struct simple_xattr. Size of this
> structure depends on userspace and can grow over 4Kb.
> 
> Signed-off-by: Vasily Averin <vvs@openvz.org>

Reviewed-by: Muchun Song <songmuchun@bytedance.com>
diff mbox series

Patch

diff --git a/fs/xattr.c b/fs/xattr.c
index 998045165916..31305b941756 100644
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -950,7 +950,7 @@  struct simple_xattr *simple_xattr_alloc(const void *value, size_t size)
 	if (len < sizeof(*new_xattr))
 		return NULL;
 
-	new_xattr = kvmalloc(len, GFP_KERNEL);
+	new_xattr = kvmalloc(len, GFP_KERNEL_ACCOUNT);
 	if (!new_xattr)
 		return NULL;