From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934849AbdKPMsR (ORCPT ); Thu, 16 Nov 2017 07:48:17 -0500 Received: from LGEAMRELO11.lge.com ([156.147.23.51]:60162 "EHLO lgeamrelo11.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934699AbdKPMsJ (ORCPT ); Thu, 16 Nov 2017 07:48:09 -0500 X-Original-SENDERIP: 156.147.1.126 X-Original-MAILFROM: byungchul.park@lge.com X-Original-SENDERIP: 10.177.222.184 X-Original-MAILFROM: byungchul.park@lge.com Subject: Re: [PATCH 1/3] lockdep: Apply crossrelease to PG_locked locks To: Michal Hocko Cc: peterz@infradead.org, mingo@kernel.org, akpm@linux-foundation.org, tglx@linutronix.de, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-block@vger.kernel.org, kernel-team@lge.com, jack@suse.cz, jlayton@redhat.com, viro@zeniv.linux.org.uk, hannes@cmpxchg.org, npiggin@gmail.com, rgoldwyn@suse.com, vbabka@suse.cz, pombredanne@nexb.com, vinmenon@codeaurora.org, gregkh@linuxfoundation.org References: <1510802067-18609-1-git-send-email-byungchul.park@lge.com> <1510802067-18609-2-git-send-email-byungchul.park@lge.com> <20171116120216.nxbwkj5y3kvim6cj@dhcp22.suse.cz> From: Byungchul Park Message-ID: Date: Thu, 16 Nov 2017 21:48:05 +0900 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.4.0 MIME-Version: 1.0 In-Reply-To: <20171116120216.nxbwkj5y3kvim6cj@dhcp22.suse.cz> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/16/2017 9:02 PM, Michal Hocko wrote: > for each struct page. So you are doubling the size. Who is going to > enable this config option? You are moving this to page_ext in a later > patch which is a good step but it doesn't go far enough because this > still consumes those resources. Is there any problem to make this > kernel command line controllable? Something we do for page_owner for > example? Sure. I will add it. > Also it would be really great if you could give us some measures about > the runtime overhead. I do not expect it to be very large but this is The major overhead would come from the amount of additional memory consumption for 'lockdep_map's. Do you want me to measure the overhead by the additional memory consumption? Or do you expect another overhead? Could you tell me what kind of result you want to get? > something people are usually interested in when enabling debugging > features. -- Thanks, Byungchul