From b5a84319a4343a0db753436fd8147e61eaafa7ea Mon Sep 17 00:00:00 2001 From: KAMEZAWA Hiroyuki Date: Wed, 7 Jan 2009 18:08:35 -0800 Subject: memcg: fix shmem's swap accounting Now, you can see following even when swap accounting is enabled. 1. Create Group 01, and 02. 2. allocate a "file" on tmpfs by a task under 01. 3. swap out the "file" (by memory pressure) 4. Read "file" from a task in group 02. 5. the charge of "file" is moved to group 02. This is not ideal behavior. This is because SwapCache which was loaded by read-ahead is not taken into account.. This is a patch to fix shmem's swapcache behavior. - remove mem_cgroup_cache_charge_swapin(). - Add SwapCache handler routine to mem_cgroup_cache_charge(). By this, shmem's file cache is charged at add_to_page_cache() with GFP_NOWAIT. - pass the page of swapcache to shrink_mem_cgroup. Signed-off-by: KAMEZAWA Hiroyuki Cc: Daisuke Nishimura Cc: Balbir Singh Cc: Paul Menage Cc: Li Zefan Cc: Hugh Dickins Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/shmem.c | 30 ++++++++++++------------------ 1 file changed, 12 insertions(+), 18 deletions(-) (limited to 'mm/shmem.c') diff --git a/mm/shmem.c b/mm/shmem.c index bbb7b04..5d0de96 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -929,11 +929,11 @@ found: if (!inode) goto out; /* - * Charge page using GFP_HIGHUSER_MOVABLE while we can wait. - * charged back to the user(not to caller) when swap account is used. + * Charge page using GFP_KERNEL while we can wait. + * Charged back to the user(not to caller) when swap account is used. + * add_to_page_cache() will be called with GFP_NOWAIT. */ - error = mem_cgroup_cache_charge_swapin(page, current->mm, GFP_KERNEL, - true); + error = mem_cgroup_cache_charge(page, current->mm, GFP_KERNEL); if (error) goto out; error = radix_tree_preload(GFP_KERNEL); @@ -1270,16 +1270,6 @@ repeat: goto repeat; } wait_on_page_locked(swappage); - /* - * We want to avoid charge at add_to_page_cache(). - * charge against this swap cache here. - */ - if (mem_cgroup_cache_charge_swapin(swappage, - current->mm, gfp & GFP_RECLAIM_MASK, false)) { - page_cache_release(swappage); - error = -ENOMEM; - goto failed; - } page_cache_release(swappage); goto repeat; } @@ -1334,15 +1324,19 @@ repeat: } else { shmem_swp_unmap(entry); spin_unlock(&info->lock); - unlock_page(swappage); - page_cache_release(swappage); if (error == -ENOMEM) { /* allow reclaim from this memory cgroup */ - error = mem_cgroup_shrink_usage(current->mm, + error = mem_cgroup_shrink_usage(swappage, + current->mm, gfp); - if (error) + if (error) { + unlock_page(swappage); + page_cache_release(swappage); goto failed; + } } + unlock_page(swappage); + page_cache_release(swappage); goto repeat; } } else if (sgp == SGP_READ && !filepage) { -- cgit v1.1