Messages in this thread Patch in this message | | | Date | Tue, 7 Oct 2008 19:03:31 +0900 | From | KAMEZAWA Hiroyuki <> | Subject | [PATCH 1/6] memcg: move charge swapin under lock |
| |
While page-cache's charge/uncharge is done under page_lock(), swap-cache isn't. (anonymous page is charged when it's newly allocated.)
This patch moves do_swap_page()'s charge() call under lock. I don't see any bad problem *now* but this fix will be good for future for avoiding unneccesary racy state.
Changelog: (v6) -> (v7) - no changes. Changelog: (v5) -> (v6) - mark_page_accessed() is moved before lock_page(). - fixed missing unlock_page() (no changes in previous version)
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
mm/memory.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-)
Index: mmotm-2.6.27-rc7+/mm/memory.c =================================================================== --- mmotm-2.6.27-rc7+.orig/mm/memory.c +++ mmotm-2.6.27-rc7+/mm/memory.c @@ -2326,16 +2326,17 @@ static int do_swap_page(struct mm_struct count_vm_event(PGMAJFAULT); } + mark_page_accessed(page); + + lock_page(page); + delayacct_clear_flag(DELAYACCT_PF_SWAPIN); + if (mem_cgroup_charge(page, mm, GFP_KERNEL)) { - delayacct_clear_flag(DELAYACCT_PF_SWAPIN); ret = VM_FAULT_OOM; + unlock_page(page); goto out; } - mark_page_accessed(page); - lock_page(page); - delayacct_clear_flag(DELAYACCT_PF_SWAPIN); - /* * Back out if somebody else already faulted in this pte. */
| |