memcg: mem_cgroup_charge never NULL
authorHugh Dickins <hugh@veritas.com>
Tue, 4 Mar 2008 22:29:08 +0000 (14:29 -0800)
committerLinus Torvalds <torvalds@woody.linux-foundation.org>
Wed, 5 Mar 2008 00:35:15 +0000 (16:35 -0800)
commit7e924aafa4b03ff71de34af8553d9a1ebc86c071
tree21735b7369ede27f34c41184b0a686020b80e2c6
parent9442ec9df40d952b0de185ae5638a74970388e01
memcg: mem_cgroup_charge never NULL

My memcgroup patch to fix hang with shmem/tmpfs added NULL page handling to
mem_cgroup_charge_common.  It seemed convenient at the time, but hard to
justify now: there's a perfectly appropriate swappage to charge and uncharge
instead, this is not on any hot path through shmem_getpage, and no performance
hit was observed from the slight extra overhead.

So revert that NULL page handling from mem_cgroup_charge_common; and make it
clearer by bringing page_cgroup_assign_new_page_cgroup into its body - that
was a helper I found more of a hindrance to understanding.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Cc: David Rientjes <rientjes@google.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hirokazu Takahashi <taka@valinux.co.jp>
Cc: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Cc: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/memcontrol.c
mm/shmem.c