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@xxxxxxxxxx> Reviewed-by: Roman Gushchin <roman.gushchin@xxxxxxxxx> Reviewed-by: Michal Koutný <mkoutny@xxxxxxxx> Acked-by: Shakeel Butt <shakeelb@xxxxxxxxxx> Reviewed-by: Muchun Song <songmuchun@xxxxxxxxxxxxx> --- fs/xattr.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/xattr.c b/fs/xattr.c index e8dd03e4561e..98dcf6600bd9 100644 --- a/fs/xattr.c +++ b/fs/xattr.c @@ -1001,7 +1001,7 @@ 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; -- 2.36.1
