From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail190.messagelabs.com (mail190.messagelabs.com [216.82.249.51]) by kanga.kvack.org (Postfix) with SMTP id 6001F6B003D for ; Fri, 11 Dec 2009 09:08:44 -0500 (EST) Received: by pwi1 with SMTP id 1so738966pwi.6 for ; Fri, 11 Dec 2009 06:08:42 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <4B224E7A.2060708@redhat.com> References: <20091210185626.26f9828a@cuia.bos.redhat.com> <28c262360912101803i7b43db78se8cf9ec61d92ee0f@mail.gmail.com> <4B2235F0.4080606@redhat.com> <28c262360912110541m2839e151hc9d49b0c251e1b67@mail.gmail.com> <4B224E7A.2060708@redhat.com> Date: Fri, 11 Dec 2009 23:08:42 +0900 Message-ID: <28c262360912110608y13c76af0g4acff99d39173493@mail.gmail.com> Subject: Re: [PATCH] vmscan: limit concurrent reclaimers in shrink_zone From: Minchan Kim Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Sender: owner-linux-mm@kvack.org To: Rik van Riel Cc: lwoodman@redhat.com, kosaki.motohiro@jp.fujitsu.com, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, aarcange@redhat.com List-ID: On Fri, Dec 11, 2009 at 10:51 PM, Rik van Riel wrote: > On 12/11/2009 08:41 AM, Minchan Kim wrote: >> >> Hi, Larry. >> >> On Fri, Dec 11, 2009 at 9:07 PM, Larry Woodman >> =C2=A0wrote: >>> >>> Minchan Kim wrote: >>>> >>>> I like this. but why do you select default value as constant 8? >>>> Do you have any reason? >>>> >>>> I think it would be better to select the number proportional to NR_CPU= . >>>> ex) NR_CPU * 2 or something. >>>> >>>> Otherwise looks good to me. >>>> >>>> Reviewed-by: Minchan Kim >>>> >>>> >>> >>> This is a per-zone count so perhaps a reasonable default is the number = of >>> CPUs on the >>> NUMA node that the zone resides on ? >> >> For example, It assume one CPU per node. >> It means your default value is 1. >> On the CPU, process A try to reclaim HIGH zone. >> Process B want to reclaim NORMAL zone. >> But Process B can't enter reclaim path sincev throttle default value is = 1 >> Even kswap can't reclaim. > > 1) the value is per zone, so process B can go ahead Sorry. I misunderstood Larry's point. I though Larry mentioned global limit not per zone. > 2) kswapd is always excempt from this limit, since > =C2=A0 there is only 1 kswapd per node anyway Larry could test with Rik's patch for what's good default value. If it proves NR_CPU on node is proper as default value, We can change default value with it. > -- > All rights reversed. > --=20 Kind regards, Minchan Kim -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org