linux-kernel - Re: [PATCH v17 1/7] mm: support madvise(MADV

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Message-ID: <20150206183242.GB2290@kernel.org>
Date:	Fri, 6 Feb 2015 10:32:42 -0800
From:	Shaohua Li <shli@...nel.org>
To:	Michal Hocko <mhocko@...e.cz>
Cc:	Minchan Kim <minchan@...nel.org>,
	"Michael Kerrisk (man-pages)" <mtk.manpages@...il.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	linux-kernel@...r.kernel.org, linux-mm@...ck.org,
	linux-api@...r.kernel.org, Hugh Dickins <hughd@...gle.com>,
	Johannes Weiner <hannes@...xchg.org>,
	Rik van Riel <riel@...hat.com>,
	KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>,
	Mel Gorman <mgorman@...e.de>, Jason Evans <je@...com>,
	zhangyanfei@...fujitsu.com,
	"Kirill A. Shutemov" <kirill@...temov.name>,
	"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
Subject: Re: [PATCH v17 1/7] mm: support madvise(MADV_FREE)

On Fri, Feb 06, 2015 at 01:58:25PM +0100, Michal Hocko wrote:
> On Thu 05-02-15 16:33:11, Shaohua Li wrote:
> [...]
> > Did you think about move the MADV_FREE pages to the head of inactive LRU, so
> > they can be reclaimed easily?
> 
> Yes this makes sense for pages living on the active LRU list. I would
> preserve LRU ordering on the inactive list because there is no good
> reason to make the operation more costly for inactive pages. On the
> other hand having tons of to-be-freed pages on the active list clearly
> sucks. Care to send a patch?

Considering anon pages are in active LRU first, it's likely MADV_FREE pages are
in active list. I'm curious why preserves the order of inactive list. App knows
which pages are cold, why don't take the advantages? I'll play the patch more
to see what I can do for it.

Thanks,
Shaohua
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