From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx185.postini.com [74.125.245.185]) by kanga.kvack.org (Postfix) with SMTP id 4EF6B6B00F5 for ; Fri, 6 Apr 2012 14:57:50 -0400 (EDT) Message-ID: <4F7F3CA9.1030500@redhat.com> Date: Fri, 06 Apr 2012 14:57:45 -0400 From: Rik van Riel MIME-Version: 1.0 Subject: Re: [PATCH V8] Eliminate task stack trace duplication References: <1333737920-17555-1-git-send-email-yinghan@google.com> In-Reply-To: <1333737920-17555-1-git-send-email-yinghan@google.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Ying Han Cc: Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org On 04/06/2012 02:45 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. This problem occurs when dumping > lots of stacks in a single operation, such as sysrq-T. > > This patch tries to reduce the duplication of task stack trace in the dump > message by hashing the task stack. The hashtable is a 32k pre-allocated buffer > during bootup. Each time if we find the identical task trace in the task stack, > we dump only the pid of the task which has the task trace dumped. So it is easy > to back track to the full stack with the pid. > Signed-off-by: Ying Han Acked-by: Rik van Riel -- 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