From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail172.messagelabs.com (mail172.messagelabs.com [216.82.254.3]) by kanga.kvack.org (Postfix) with ESMTP id 2D12A8D003A for ; Sun, 20 Feb 2011 10:17:38 -0500 (EST) Received: by mail-iy0-f169.google.com with SMTP id 13so1913106iyf.14 for ; Sun, 20 Feb 2011 07:17:36 -0800 (PST) From: Minchan Kim Subject: [PATCH v2 2/2] memcg: remove charge variable in unmap_and_move Date: Mon, 21 Feb 2011 00:17:18 +0900 Message-Id: In-Reply-To: References: In-Reply-To: References: Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: linux-mm , LKML , Johannes Weiner , Balbir Singh , KAMEZAWA Hiroyuki , Daisuke Nishimura , Minchan Kim memcg charge/uncharge could be handled by mem_cgroup_[prepare/end] migration itself so charge local variable in unmap_and_move lost the role since we introduced 01b1ae63c2. In addition, the variable name is not good like below. int unmap_and_move() { charge = mem_cgroup_prepare_migration(xxx); .. BUG_ON(charge); <-- BUG if it is charged? .. uncharge: if (!charge) <-- why do we have to uncharge !charge? mem_group_end_migration(xxx); .. } So let's remove unnecessary and confusing variable. Cc: Johannes Weiner Cc: Balbir Singh Suggested-by: Daisuke Nishimura Acked-by: Daisuke Nishimura Acked-by: KAMEZAWA Hiroyuki Signed-off-by: Minchan Kim --- mm/memcontrol.c | 1 + mm/migrate.c | 9 +++------ 2 files changed, 4 insertions(+), 6 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 8a97571..3c91d5c 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -2873,6 +2873,7 @@ static inline int mem_cgroup_move_swap_account(swp_entry_t entry, /* * Before starting migration, account PAGE_SIZE to mem_cgroup that the old * page belongs to. + * Note: Should not return -EAGAIN. unmap_and_move depens on it. */ int mem_cgroup_prepare_migration(struct page *page, struct page *newpage, struct mem_cgroup **ptr, gfp_t gfp_mask) diff --git a/mm/migrate.c b/mm/migrate.c index 2abc9c9..37055d0 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -622,7 +622,6 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private, int *result = NULL; struct page *newpage = get_new_page(page, private, &result); int remap_swapcache = 1; - int charge = 0; struct mem_cgroup *mem; struct anon_vma *anon_vma = NULL; @@ -637,7 +636,7 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private, if (unlikely(split_huge_page(page))) goto move_newpage; - /* prepare cgroup just returns 0 or -ENOMEM */ + /* mem_cgroup_prepage_migration never returns -EAGAIN */ rc = -EAGAIN; if (!trylock_page(page)) { @@ -678,8 +677,7 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private, } /* charge against new page */ - charge = mem_cgroup_prepare_migration(page, newpage, &mem, GFP_KERNEL); - if (charge == -ENOMEM) { + if (mem_cgroup_prepare_migration(page, newpage, &mem, GFP_KERNEL)) { rc = -ENOMEM; goto unlock; } @@ -766,8 +764,7 @@ skip_unmap: drop_anon_vma(anon_vma); uncharge: - if (!charge) - mem_cgroup_end_migration(mem, page, newpage, rc == 0); + mem_cgroup_end_migration(mem, page, newpage, rc == 0); unlock: unlock_page(page); -- 1.7.1 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org