From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail191.messagelabs.com (mail191.messagelabs.com [216.82.242.19]) by kanga.kvack.org (Postfix) with SMTP id 96DB26B00EA for ; Tue, 11 Jan 2011 03:51:26 -0500 (EST) Received: by gxk28 with SMTP id 28so3202878gxk.2 for ; Tue, 11 Jan 2011 00:51:25 -0800 (PST) From: Minchan Kim Subject: [PATCH 2/2] memcg: remove charge variable in unmap_and_move Date: Tue, 11 Jan 2011 17:51:12 +0900 Message-Id: In-Reply-To: <41390917af25769cd59eb001370b80ef6520a8bb.1294735182.git.minchan.kim@gmail.com> References: <41390917af25769cd59eb001370b80ef6520a8bb.1294735182.git.minchan.kim@gmail.com> In-Reply-To: <41390917af25769cd59eb001370b80ef6520a8bb.1294735182.git.minchan.kim@gmail.com> References: <41390917af25769cd59eb001370b80ef6520a8bb.1294735182.git.minchan.kim@gmail.com> Sender: owner-linux-mm@kvack.org To: Andrew Morton Cc: linux-mm , LKML , KAMEZAWA Hiroyuki , Balbir Singh , Daisuke Nishimura , Minchan Kim List-ID: 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. Suggested-by: Daisuke Nishimura Cc: Balbir Singh Cc: 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 8ab8410..b1b572f 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -2804,6 +2804,7 @@ 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 depends on it. */ int mem_cgroup_prepare_migration(struct page *page, struct page *newpage, struct mem_cgroup **ptr) diff --git a/mm/migrate.c b/mm/migrate.c index 8f0f131..5f2169f 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -623,7 +623,6 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private, struct page *newpage = get_new_page(page, private, &result); int remap_swapcache = 1; int rcu_locked = 0; - int charge = 0; struct mem_cgroup *mem = NULL; struct anon_vma *anon_vma = NULL; @@ -638,7 +637,7 @@ 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_prepare_migration never returns -EAGAIN */ rc = -EAGAIN; if (!trylock_page(page)) { @@ -662,8 +661,7 @@ 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); - if (charge == -ENOMEM) { + if (mem_cgroup_prepare_migration(page, newpage, &mem)) { rc = -ENOMEM; goto unlock; } @@ -759,8 +757,7 @@ rcu_unlock: if (rcu_locked) rcu_read_unlock(); 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); -- 1.7.0.4 -- 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 policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: email@kvack.org