linux-kernel - Re: [PATCH V5 3/6] mm: move MADV_FREE pages into LRU_INACTIVE

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Message-ID: <06ef01d29171$7ace0620$706a1260$@alibaba-inc.com>
Date:   Tue, 28 Feb 2017 11:19:31 +0800
From:   "Hillf Danton" <hillf.zj@...baba-inc.com>
To:     "'Shaohua Li'" <shli@...com>, <linux-mm@...ck.org>,
        <linux-kernel@...r.kernel.org>
Cc:     <Kernel-team@...com>, <mhocko@...e.com>, <minchan@...nel.org>,
        <hughd@...gle.com>, <hannes@...xchg.org>, <riel@...hat.com>,
        <mgorman@...hsingularity.net>, <akpm@...ux-foundation.org>
Subject: Re: [PATCH V5 3/6] mm: move MADV_FREE pages into LRU_INACTIVE_FILE list

On February 25, 2017 5:32 AM Shaohua Li wrote: 
> 
> madv MADV_FREE indicate pages are 'lazyfree'. They are still anonymous
> pages, but they can be freed without pageout. To destinguish them
> against normal anonymous pages, we clear their SwapBacked flag.
> 
> MADV_FREE pages could be freed without pageout, so they pretty much like
> used once file pages. For such pages, we'd like to reclaim them once
> there is memory pressure. Also it might be unfair reclaiming MADV_FREE
> pages always before used once file pages and we definitively want to
> reclaim the pages before other anonymous and file pages.
> 
> To speed up MADV_FREE pages reclaim, we put the pages into
> LRU_INACTIVE_FILE list. The rationale is LRU_INACTIVE_FILE list is tiny
> nowadays and should be full of used once file pages. Reclaiming
> MADV_FREE pages will not have much interfere of anonymous and active
> file pages. And the inactive file pages and MADV_FREE pages will be
> reclaimed according to their age, so we don't reclaim too many MADV_FREE
> pages too. Putting the MADV_FREE pages into LRU_INACTIVE_FILE_LIST also
> means we can reclaim the pages without swap support. This idea is
> suggested by Johannes.
> 
> This patch doesn't move MADV_FREE pages to LRU_INACTIVE_FILE list yet to
> avoid bisect failure, next patch will do it.
> 
> The patch is based on Minchan's original patch.
> 
> Cc: Michal Hocko <mhocko@...e.com>
> Cc: Minchan Kim <minchan@...nel.org>
> Cc: Hugh Dickins <hughd@...gle.com>
> Cc: Rik van Riel <riel@...hat.com>
> Cc: Mel Gorman <mgorman@...hsingularity.net>
> Cc: Andrew Morton <akpm@...ux-foundation.org>
> Suggested-by: Johannes Weiner <hannes@...xchg.org>
> Signed-off-by: Shaohua Li <shli@...com>
> ---

Acked-by: Hillf Danton <hillf.zj@...baba-inc.com>