From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
To: Johannes Weiner <hannes@cmpxchg.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Michal Hocko <mhocko@suse.cz>,
Balbir Singh <bsingharora@gmail.com>,
cgroups@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [patch 5/8] mm: memcg: remove unneeded checks from newpage_charge()
Date: Thu, 24 Nov 2011 09:04:43 +0900 [thread overview]
Message-ID: <20111124090443.d3f720c5.kamezawa.hiroyu@jp.fujitsu.com> (raw)
In-Reply-To: <1322062951-1756-6-git-send-email-hannes@cmpxchg.org>
On Wed, 23 Nov 2011 16:42:28 +0100
Johannes Weiner <hannes@cmpxchg.org> wrote:
> From: Johannes Weiner <jweiner@redhat.com>
>
> All callsites pass in freshly allocated pages and a valid mm. As a
> result, all checks pertaining the page's mapcount, page->mapping or
> the fallback to init_mm are unneeded.
>
> Signed-off-by: Johannes Weiner <jweiner@redhat.com>
Hmm, it's true now. But for making clear our assumption to all readers of code,
could you add
VM_BUG_ON(!mm || page_mapped(page) || (page->mapping && !PageAnon(page)) ?
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
> ---
> mm/memcontrol.c | 13 +------------
> 1 files changed, 1 insertions(+), 12 deletions(-)
>
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index d4d139a..0d10be4 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -2679,19 +2679,8 @@ int mem_cgroup_newpage_charge(struct page *page,
> {
> if (mem_cgroup_disabled())
> return 0;
> - /*
> - * If already mapped, we don't have to account.
> - * If page cache, page->mapping has address_space.
> - * But page->mapping may have out-of-use anon_vma pointer,
> - * detecit it by PageAnon() check. newly-mapped-anon's page->mapping
> - * is NULL.
> - */
> - if (page_mapped(page) || (page->mapping && !PageAnon(page)))
> - return 0;
> - if (unlikely(!mm))
> - mm = &init_mm;
> return mem_cgroup_charge_common(page, mm, gfp_mask,
> - MEM_CGROUP_CHARGE_TYPE_MAPPED);
> + MEM_CGROUP_CHARGE_TYPE_MAPPED);
> }
>
> static void
> --
> 1.7.6.4
>
> --
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>
next prev parent reply other threads:[~2011-11-24 0:05 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-23 15:42 [patch 0/8] mm: memcg fixlets for 3.3 Johannes Weiner
2011-11-23 15:42 ` [patch 1/8] mm: oom_kill: remove memcg argument from oom_kill_task() Johannes Weiner
2011-11-23 22:35 ` David Rientjes
2011-11-23 23:57 ` KAMEZAWA Hiroyuki
2011-11-24 9:07 ` Michal Hocko
2011-11-28 0:37 ` Balbir Singh
2011-11-23 15:42 ` [patch 2/8] mm: unify remaining mem_cont, mem, etc. variable names to memcg Johannes Weiner
2011-11-23 22:40 ` David Rientjes
2011-11-23 23:58 ` KAMEZAWA Hiroyuki
2011-11-24 9:17 ` Michal Hocko
2011-11-28 0:42 ` Balbir Singh
2011-11-23 15:42 ` [patch 3/8] mm: memcg: clean up fault accounting Johannes Weiner
2011-11-24 0:00 ` KAMEZAWA Hiroyuki
2011-11-24 9:33 ` Michal Hocko
2011-11-24 9:51 ` Johannes Weiner
2011-11-28 0:45 ` Balbir Singh
2011-11-23 15:42 ` [patch 4/8] mm: memcg: lookup_page_cgroup (almost) never returns NULL Johannes Weiner
2011-11-24 0:01 ` KAMEZAWA Hiroyuki
2011-11-24 9:52 ` Michal Hocko
2011-11-24 10:05 ` Johannes Weiner
2011-11-24 10:26 ` Michal Hocko
2011-11-28 9:15 ` Johannes Weiner
2011-11-28 9:34 ` Johannes Weiner
2011-11-28 10:12 ` Michal Hocko
2011-11-28 7:03 ` Balbir Singh
2011-11-28 9:17 ` Johannes Weiner
2011-11-23 15:42 ` [patch 5/8] mm: memcg: remove unneeded checks from newpage_charge() Johannes Weiner
2011-11-24 0:04 ` KAMEZAWA Hiroyuki [this message]
2011-11-24 9:04 ` Johannes Weiner
2011-11-24 10:30 ` Michal Hocko
2011-11-24 11:58 ` Johannes Weiner
2011-11-23 15:42 ` [patch 6/8] mm: memcg: remove unneeded checks from uncharge_page() Johannes Weiner
2011-11-24 0:06 ` KAMEZAWA Hiroyuki
2011-11-24 9:06 ` Johannes Weiner
2011-11-24 10:34 ` Michal Hocko
2011-11-23 15:42 ` [patch 7/8] mm: memcg: modify PageCgroupAcctLRU non-atomically Johannes Weiner
2011-11-23 18:52 ` Hugh Dickins
2011-11-24 8:53 ` Johannes Weiner
2011-11-24 0:09 ` KAMEZAWA Hiroyuki
2011-11-24 8:55 ` Johannes Weiner
2011-11-23 15:42 ` [patch 8/8] mm: memcg: modify PageCgroupCache non-atomically Johannes Weiner
2011-11-24 0:13 ` KAMEZAWA Hiroyuki
2011-11-24 9:13 ` Johannes Weiner
2011-11-24 6:09 ` [patch 0/8] mm: memcg fixlets for 3.3 Balbir Singh
2011-11-24 9:45 ` Johannes Weiner
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