Re: [patch 6/8] mm: memcg: remove unneeded checks fromuncharge_page()

From: KAMEZAWA Hiroyuki
Date: Wed Nov 23 2011 - 19:07:24 EST


On Wed, 23 Nov 2011 16:42:29 +0100
Johannes Weiner <hannes@xxxxxxxxxxx> wrote:

> From: Johannes Weiner <jweiner@xxxxxxxxxx>
>
> mem_cgroup_uncharge_page() is only called on either freshly allocated
> pages without page->mapping or on rmapped PageAnon() pages. There is
> no need to check for a page->mapping that is not an anon_vma.
>
> Signed-off-by: Johannes Weiner <jweiner@xxxxxxxxxx>

For making our assumption clearer to readers of codes,
VM_BUG_ON(page->mapping && !PageAnon(page)) please.

Anyway,
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>


> ---
> mm/memcontrol.c | 2 --
> 1 files changed, 0 insertions(+), 2 deletions(-)
>
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 0d10be4..b9a3b94 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -2989,8 +2989,6 @@ void mem_cgroup_uncharge_page(struct page *page)
> /* early check. */
> if (page_mapped(page))
> return;
> - if (page->mapping && !PageAnon(page))
> - return;
> __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_MAPPED);
> }
>
> --
> 1.7.6.4
>
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