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Message-ID: <53BB6B64.1080807@cn.fujitsu.com>
Date: Tue, 8 Jul 2014 11:54:12 +0800
From: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
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To: Minchan Kim <minchan@kernel.org>
CC: Andrew Morton <akpm@linux-foundation.org>, <linux-kernel@vger.kernel.org>,
        <linux-mm@kvack.org>, Michael Kerrisk <mtk.manpages@gmail.com>,
        Linux API <linux-api@vger.kernel.org>, Hugh Dickins <hughd@google.com>,
        Johannes Weiner <hannes@cmpxchg.org>, Rik van Riel <riel@redhat.com>,
        KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
        Mel Gorman <mgorman@suse.de>, Jason Evans <je@fb.com>,
        "Kirill A. Shutemov" <kirill@shutemov.name>
Subject: Re: [PATCH v10 1/7] mm: support madvise(MADV_FREE)
References: <1404694438-10272-1-git-send-email-minchan@kernel.org> <1404694438-10272-2-git-send-email-minchan@kernel.org>
In-Reply-To: <1404694438-10272-2-git-send-email-minchan@kernel.org>
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Hi Minchan,

On 07/07/2014 08:53 AM, Minchan Kim wrote:
> Linux doesn't have an ability to free pages lazy while other OS
> already have been supported that named by madvise(MADV_FREE).
> 
> The gain is clear that kernel can discard freed pages rather than
> swapping out or OOM if memory pressure happens.
> 
> Without memory pressure, freed pages would be reused by userspace
> without another additional overhead(ex, page fault + allocation
> + zeroing).
> 
> How to work is following as.
> 
> When madvise syscall is called, VM clears dirty bit of ptes of
> the range. 

This should be updated because the implementation has been changed.
It also remove the page from the swapcache if it is.

Thank you for your effort!

-- 
Thanks.
Zhang Yanfei
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