linux-kernel - Re: [RFC][PATCH] mm: remove unnecessary loop inside shrink_inactive

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-Id: <20090827091834.397F.A69D9226@jp.fujitsu.com>
Date:	Thu, 27 Aug 2009 09:20:35 +0900 (JST)
From:	KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>
To:	Wu Fengguang <fengguang.wu@...el.com>
Cc:	kosaki.motohiro@...fujitsu.com,
	Andrew Morton <akpm@...ux-foundation.org>,
	Balbir Singh <balbir@...ux.vnet.ibm.com>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>,
	Rik van Riel <riel@...hat.com>,
	Johannes Weiner <hannes@...xchg.org>,
	Avi Kivity <avi@...hat.com>,
	Andrea Arcangeli <aarcange@...hat.com>,
	"Dike, Jeffrey G" <jeffrey.g.dike@...el.com>,
	Hugh Dickins <hugh.dickins@...cali.co.uk>,
	Christoph Lameter <cl@...ux-foundation.org>,
	Mel Gorman <mel@....ul.ie>,
	LKML <linux-kernel@...r.kernel.org>,
	linux-mm <linux-mm@...ck.org>,
	"nishimura@....nes.nec.co.jp" <nishimura@....nes.nec.co.jp>,
	"lizf@...fujitsu.com" <lizf@...fujitsu.com>,
	"menage@...gle.com" <menage@...gle.com>
Subject: Re: [RFC][PATCH] mm: remove unnecessary loop inside shrink_inactive_list()

> On Fri, Aug 21, 2009 at 07:09:17PM +0800, KOSAKI Motohiro wrote:
> > 2009/8/20 Wu Fengguang <fengguang.wu@...el.com>:
> > > shrink_inactive_list() won't be called to scan too much pages
> > > (unless in hibernation code which is fine) or too few pages (ie.
> > > batching is taken care of by the callers).  So we can just remove the
> > > big loop and isolate the exact number of pages requested.
> > >
> > > Just a RFC, and a scratch patch to show the basic idea.
> > > Please kindly NAK quick if you don't like it ;)
> > 
> > Hm, I think this patch taks only cleanups. right?
> > if so, I don't find any objection reason.
> 
> Mostly cleanups, but one behavior change here: 
> 
> > > -               nr_taken = sc->isolate_pages(sc->swap_cluster_max,
> > > +               nr_taken = sc->isolate_pages(nr_to_scan,
> > >                             &page_list, &nr_scan, sc->order, mode,
> > >                                zone, sc->mem_cgroup, 0, file);
> 
> The new behavior is to scan exactly the number of pages that
> shrink_zone() or other callers tell it. It won't try to "round it up"
> to 32 pages. This new behavior is in line with shrink_active_list()'s
> current status as well as shrink_zone()'s expectation.
> 
> shrink_zone() may still submit scan requests for <32 pages, which is
> suboptimal. I'll try to eliminate that totally with more patches.

Your explanation seems makes sense.
I'll wait your next spin :)





--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/