From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f41.google.com (mail-pa0-f41.google.com [209.85.220.41]) by kanga.kvack.org (Postfix) with ESMTP id 77CD96B0039 for ; Fri, 11 Jul 2014 10:57:32 -0400 (EDT) Received: by mail-pa0-f41.google.com with SMTP id fb1so1618852pad.28 for ; Fri, 11 Jul 2014 07:57:32 -0700 (PDT) Received: from mail-pd0-x236.google.com (mail-pd0-x236.google.com [2607:f8b0:400e:c02::236]) by mx.google.com with ESMTPS id gg2si2654525pbb.253.2014.07.11.07.57.30 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Fri, 11 Jul 2014 07:57:31 -0700 (PDT) Received: by mail-pd0-f182.google.com with SMTP id p10so1199696pdj.27 for ; Fri, 11 Jul 2014 07:57:30 -0700 (PDT) Date: Fri, 11 Jul 2014 07:55:50 -0700 (PDT) From: Hugh Dickins Subject: Re: + shmem-fix-faulting-into-a-hole-while-its-punched-take-2.patch added to -mm tree In-Reply-To: <53BFD708.1040305@oracle.com> Message-ID: References: <53BD1053.5020401@suse.cz> <53BD39FC.7040205@oracle.com> <53BD67DC.9040700@oracle.com> <53BE8B1B.3000808@oracle.com> <53BECBA4.3010508@oracle.com> <53BED7F6.4090502@oracle.com> <53BEE345.4090203@oracle.com> <20140711082500.GB20603@laptop.programming.kicks-ass.net> <53BFD708.1040305@oracle.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Peter Zijlstra Cc: Sasha Levin , Hugh Dickins , Heiko Carstens , Vlastimil Babka , akpm@linux-foundation.org, davej@redhat.com, koct9i@gmail.com, lczerner@redhat.com, stable@vger.kernel.org, "linux-mm@kvack.org" , LKML On Fri, 11 Jul 2014, Sasha Levin wrote: > > There's no easy way to see whether a given task is actually holding a lock or > is just blocking on it without going through all those tasks one by one and > looking at their trace. > > I agree with you that "The call trace is very clear on it that its not", but > when you have 500 call traces you really want something better than going > through it one call trace at a time. Points well made, and I strongly agree with Vlastimil and Sasha. There is a world of difference between a lock wanted and a lock held, and for the display of locks "held" to conceal that difference is unhelpful. It just needs one greppable word to distinguish the cases. (Though I didn't find "The call trace is very clear on it that its not", I thought it too was telling me that the lock was already held somehow.) Hugh -- 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