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
| ||
|
Date: Mon, 2 Aug 2010 13:13:21 +0900 (JST) From: KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com> To: Minchan Kim <minchan.kim@...il.com> Cc: kosaki.motohiro@...fujitsu.com, Wu Fengguang <fengguang.wu@...el.com>, Andrew Morton <akpm@...ux-foundation.org>, Mel Gorman <mel@....ul.ie>, Andy Whitcroft <apw@...dowen.org>, Rik van Riel <riel@...hat.com>, Christoph Hellwig <hch@...radead.org>, "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, "linux-fsdevel@...r.kernel.org" <linux-fsdevel@...r.kernel.org>, "linux-mm@...ck.org" <linux-mm@...ck.org>, Dave Chinner <david@...morbit.com>, Chris Mason <chris.mason@...cle.com>, Nick Piggin <npiggin@...e.de>, Johannes Weiner <hannes@...xchg.org>, KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>, Andrea Arcangeli <aarcange@...hat.com>, Andreas Mohr <andi@...as.de>, Bill Davidsen <davidsen@....com>, Ben Gamari <bgamari.foss@...il.com> Subject: Re: [PATCH] vmscan: synchronous lumpy reclaim don't call congestion_wait() > Hi KOSAKI, > > On Sun, Aug 01, 2010 at 06:12:47PM +0900, KOSAKI Motohiro wrote: > > rebased onto Wu's patch > > > > ---------------------------------------------- > > From 35772ad03e202c1c9a2252de3a9d3715e30d180f Mon Sep 17 00:00:00 2001 > > From: KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com> > > Date: Sun, 1 Aug 2010 17:23:41 +0900 > > Subject: [PATCH] vmscan: synchronous lumpy reclaim don't call congestion_wait() > > > > congestion_wait() mean "waiting for number of requests in IO queue is > > under congestion threshold". > > That said, if the system have plenty dirty pages, flusher thread push > > new request to IO queue conteniously. So, IO queue are not cleared > > congestion status for a long time. thus, congestion_wait(HZ/10) is > > almostly equivalent schedule_timeout(HZ/10). > Just a nitpick. > Why is it a problem? > HZ/10 is upper bound we intended. If is is rahter high, we can low it. > But totally I agree on this patch. It would be better to remove it > than lowing. because all of _unnecessary_ sleep is evil. the problem is, congestion_wait() mean "wait until queue congestion will be cleared, iow, wait all of IO". but we want to wait until _my_ IO finished. So, if flusher thread conteniously push new IO into the queue, that makes big difference. Thanks. -- 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/
Powered by blists - more mailing lists