From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx175.postini.com [74.125.245.175]) by kanga.kvack.org (Postfix) with SMTP id 5096D6B0044 for ; Thu, 26 Apr 2012 15:33:39 -0400 (EDT) Received: by lbbgg6 with SMTP id gg6so1717735lbb.14 for ; Thu, 26 Apr 2012 12:33:37 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <4F7F3CA9.1030500@redhat.com> References: <1333737920-17555-1-git-send-email-yinghan@google.com> <4F7F3CA9.1030500@redhat.com> Date: Thu, 26 Apr 2012 12:33:36 -0700 Message-ID: Subject: Re: [PATCH V8] Eliminate task stack trace duplication From: Ying Han Content-Type: text/plain; charset=ISO-8859-1 Sender: owner-linux-mm@kvack.org List-ID: To: Rik van Riel Cc: Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Ingo Molnar , "H. Peter Anvin" , tglx@linutronix.de, x86@kernel.org ++cc x86 people which I forgot this time .. --Ying On Fri, Apr 6, 2012 at 11:57 AM, Rik van Riel wrote: > 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