From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail203.messagelabs.com (mail203.messagelabs.com [216.82.254.243]) by kanga.kvack.org (Postfix) with ESMTP id 5277F6B0011 for ; Tue, 3 May 2011 16:10:12 -0400 (EDT) Received: from wpaz24.hot.corp.google.com (wpaz24.hot.corp.google.com [172.24.198.88]) by smtp-out.google.com with ESMTP id p43KA9Kk013521 for ; Tue, 3 May 2011 13:10:09 -0700 Received: from gxk10 (gxk10.prod.google.com [10.202.11.10]) by wpaz24.hot.corp.google.com with ESMTP id p43KA8Cc007979 (version=TLSv1/SSLv3 cipher=RC4-SHA bits=128 verify=NOT) for ; Tue, 3 May 2011 13:10:08 -0700 Received: by gxk10 with SMTP id 10so242252gxk.11 for ; Tue, 03 May 2011 13:10:08 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <4DC0483F.50609@redhat.com> References: <1304444135-14128-1-git-send-email-yinghan@google.com> <4DC0483F.50609@redhat.com> Date: Tue, 3 May 2011 13:10:08 -0700 Message-ID: Subject: Re: [PATCH] Eliminate task stack trace duplication. From: Ying Han Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Sender: owner-linux-mm@kvack.org List-ID: To: Rik van Riel Cc: KOSAKI Motohiro , Minchan Kim , Daisuke Nishimura , Balbir Singh , Tejun Heo , Pavel Emelyanov , KAMEZAWA Hiroyuki , Andrew Morton , Li Zefan , Mel Gorman , Christoph Lameter , Johannes Weiner , Hugh Dickins , Michal Hocko , Salman Qazi , Dave Hansen , Zhu Yanhai , linux-mm@kvack.org On Tue, May 3, 2011 at 11:23 AM, Rik van Riel wrote: > On 05/03/2011 01:35 PM, Ying Han wrote: >> >> The problem with small dmesg ring buffer like 512k is that only limited >> number >> of task traces will be logged. Sometimes we lose important information >> only >> because of too many duplicated stack traces. > > I like it. =A0I often overlook information from staring > myself blind on way too many duplicate stack traces. > >> This patch tries to reduce the duplication of task stack trace in the du= mp >> message by hashing the task stack. The hashtable is a 32k pre-allocated >> buffer >> during bootup. > > This changelog doesn't tell the whole story of what > the code does. Thanks Rik for reviewing it. I can add more details to the changelog . --Ying > > It appears to store stack traces in the table, and > use the hash to look them up. Somehow there's a global > pointer, called cur_stack, involved too. > > The code looks correct, but somehow I'm not happy with > it. Having said that, I also don't have ideas on how to > make it better. > > If nobody else knows how to make this code better, maybe > it should just be merged as is. I hope someone has ideas, > though :) > > -- > All rights reversed > -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org