linux-kernel - Re: [PATCH 0/5] Volatile Ranges (v12) & LSF-MM discussion fodder

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Date:	Wed, 02 Apr 2014 10:40:14 -0700
From:	Dave Hansen <dave@...1.net>
To:	Johannes Weiner <hannes@...xchg.org>,
	"H. Peter Anvin" <hpa@...or.com>
CC:	John Stultz <john.stultz@...aro.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Android Kernel Team <kernel-team@...roid.com>,
	Robert Love <rlove@...gle.com>, Mel Gorman <mel@....ul.ie>,
	Hugh Dickins <hughd@...gle.com>,
	Rik van Riel <riel@...hat.com>,
	Dmitry Adamushko <dmitry.adamushko@...il.com>,
	Neil Brown <neilb@...e.de>,
	Andrea Arcangeli <aarcange@...hat.com>,
	Mike Hommey <mh@...ndium.org>, Taras Glek <tglek@...illa.com>,
	Jan Kara <jack@...e.cz>,
	KOSAKI Motohiro <kosaki.motohiro@...il.com>,
	Michel Lespinasse <walken@...gle.com>,
	Minchan Kim <minchan@...nel.org>,
	"linux-mm@...ck.org" <linux-mm@...ck.org>
Subject: Re: [PATCH 0/5] Volatile Ranges (v12) & LSF-MM discussion fodder

On 04/02/2014 10:18 AM, Johannes Weiner wrote:
> Hence my follow-up question in the other mail about how large we
> expect such code caches to become in practice in relationship to
> overall system memory.  Are code caches interesting reclaim candidates
> to begin with?  Are they big enough to make the machine thrash/swap
> otherwise?

A big chunk of the use cases here are for swapless systems anyway, so
this is the *only* way for them to reclaim anonymous memory.  Their
choices are either to be constantly throwing away and rebuilding these
objects, or to leave them in memory effectively pinned.

In practice I did see ashmem (the Android thing that we're trying to
replace) get used a lot by the Android web browser when I was playing
with it.  John said that it got used for storing decompressed copies of
images.
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