From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754844AbdDMRYs (ORCPT ); Thu, 13 Apr 2017 13:24:48 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:57106 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753484AbdDMRYq (ORCPT ); Thu, 13 Apr 2017 13:24:46 -0400 Date: Thu, 13 Apr 2017 10:24:38 -0700 From: "Paul E. McKenney" To: Peter Zijlstra Cc: Vlastimil Babka , linux-kernel@vger.kernel.org, mingo@kernel.org, jiangshanlai@gmail.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@efficios.com, josh@joshtriplett.org, tglx@linutronix.de, rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com, fweisbec@gmail.com, oleg@redhat.com, bobby.prani@gmail.com, Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , linux-mm@kvack.org Subject: Re: [PATCH tip/core/rcu 01/13] mm: Rename SLAB_DESTROY_BY_RCU to SLAB_TYPESAFE_BY_RCU Reply-To: paulmck@linux.vnet.ibm.com References: <20170412165441.GA17149@linux.vnet.ibm.com> <1492016149-18834-1-git-send-email-paulmck@linux.vnet.ibm.com> <20170413091248.xnctlppstkrm6eq5@hirez.programming.kicks-ass.net> <50d59b9c-fa8e-1992-2613-e84774ec5428@suse.cz> <20170413161709.ej3qxuqitykhqtyf@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170413161709.ej3qxuqitykhqtyf@hirez.programming.kicks-ass.net> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-GCONF: 00 x-cbid: 17041317-0044-0000-0000-00000304FE06 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00006930; HX=3.00000240; KW=3.00000007; PH=3.00000004; SC=3.00000208; SDB=6.00847078; UDB=6.00417893; IPR=6.00625511; BA=6.00005288; NDR=6.00000001; ZLA=6.00000005; ZF=6.00000009; ZB=6.00000000; ZP=6.00000000; ZH=6.00000000; ZU=6.00000002; MB=3.00015033; XFM=3.00000013; UTC=2017-04-13 17:24:43 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17041317-0045-0000-0000-000007330240 Message-Id: <20170413172438.GA10199@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-04-13_11:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1702020001 definitions=main-1704130146 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Apr 13, 2017 at 06:17:09PM +0200, Peter Zijlstra wrote: > On Thu, Apr 13, 2017 at 01:06:56PM +0200, Vlastimil Babka wrote: > > On 04/13/2017 11:12 AM, Peter Zijlstra wrote: > > > On Wed, Apr 12, 2017 at 09:55:37AM -0700, Paul E. McKenney wrote: > > >> A group of Linux kernel hackers reported chasing a bug that resulted > > >> from their assumption that SLAB_DESTROY_BY_RCU provided an existence > > >> guarantee, that is, that no block from such a slab would be reallocated > > >> during an RCU read-side critical section. Of course, that is not the > > >> case. Instead, SLAB_DESTROY_BY_RCU only prevents freeing of an entire > > >> slab of blocks. > > > > > > And that while we wrote a huge honking comment right along with it... > > > > > >> [ paulmck: Add "tombstone" comments as requested by Eric Dumazet. ] > > > > > > I cannot find any occurrence of "tomb" or "TOMB" in the actual patch, > > > confused? > > > > It's the comments such as: > > > > + * Note that SLAB_TYPESAFE_BY_RCU was originally named SLAB_DESTROY_BY_RCU. > > > > so that people who remember the old name can git grep its fate. > > git log -S SLAB_DESTROY_BY_RCU My (perhaps naive) hope is that having more than one path to the information will reduce the number of "Whatever happened to SLAB_DESTROY_BY_RCU?" queries. Thanx, Paul From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-io0-f197.google.com (mail-io0-f197.google.com [209.85.223.197]) by kanga.kvack.org (Postfix) with ESMTP id 672D96B03B1 for ; Thu, 13 Apr 2017 13:24:47 -0400 (EDT) Received: by mail-io0-f197.google.com with SMTP id c130so53840623ioe.19 for ; Thu, 13 Apr 2017 10:24:47 -0700 (PDT) Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com. [148.163.156.1]) by mx.google.com with ESMTPS id u125si9562244itd.15.2017.04.13.10.24.46 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 13 Apr 2017 10:24:46 -0700 (PDT) Received: from pps.filterd (m0098410.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.20/8.16.0.20) with SMTP id v3DHNX60019702 for ; Thu, 13 Apr 2017 13:24:45 -0400 Received: from e18.ny.us.ibm.com (e18.ny.us.ibm.com [129.33.205.208]) by mx0a-001b2d01.pphosted.com with ESMTP id 29t69a6e84-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Thu, 13 Apr 2017 13:24:45 -0400 Received: from localhost by e18.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 13 Apr 2017 13:24:44 -0400 Date: Thu, 13 Apr 2017 10:24:38 -0700 From: "Paul E. McKenney" Subject: Re: [PATCH tip/core/rcu 01/13] mm: Rename SLAB_DESTROY_BY_RCU to SLAB_TYPESAFE_BY_RCU Reply-To: paulmck@linux.vnet.ibm.com References: <20170412165441.GA17149@linux.vnet.ibm.com> <1492016149-18834-1-git-send-email-paulmck@linux.vnet.ibm.com> <20170413091248.xnctlppstkrm6eq5@hirez.programming.kicks-ass.net> <50d59b9c-fa8e-1992-2613-e84774ec5428@suse.cz> <20170413161709.ej3qxuqitykhqtyf@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170413161709.ej3qxuqitykhqtyf@hirez.programming.kicks-ass.net> Message-Id: <20170413172438.GA10199@linux.vnet.ibm.com> Sender: owner-linux-mm@kvack.org List-ID: To: Peter Zijlstra Cc: Vlastimil Babka , linux-kernel@vger.kernel.org, mingo@kernel.org, jiangshanlai@gmail.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@efficios.com, josh@joshtriplett.org, tglx@linutronix.de, rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com, fweisbec@gmail.com, oleg@redhat.com, bobby.prani@gmail.com, Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , linux-mm@kvack.org On Thu, Apr 13, 2017 at 06:17:09PM +0200, Peter Zijlstra wrote: > On Thu, Apr 13, 2017 at 01:06:56PM +0200, Vlastimil Babka wrote: > > On 04/13/2017 11:12 AM, Peter Zijlstra wrote: > > > On Wed, Apr 12, 2017 at 09:55:37AM -0700, Paul E. McKenney wrote: > > >> A group of Linux kernel hackers reported chasing a bug that resulted > > >> from their assumption that SLAB_DESTROY_BY_RCU provided an existence > > >> guarantee, that is, that no block from such a slab would be reallocated > > >> during an RCU read-side critical section. Of course, that is not the > > >> case. Instead, SLAB_DESTROY_BY_RCU only prevents freeing of an entire > > >> slab of blocks. > > > > > > And that while we wrote a huge honking comment right along with it... > > > > > >> [ paulmck: Add "tombstone" comments as requested by Eric Dumazet. ] > > > > > > I cannot find any occurrence of "tomb" or "TOMB" in the actual patch, > > > confused? > > > > It's the comments such as: > > > > + * Note that SLAB_TYPESAFE_BY_RCU was originally named SLAB_DESTROY_BY_RCU. > > > > so that people who remember the old name can git grep its fate. > > git log -S SLAB_DESTROY_BY_RCU My (perhaps naive) hope is that having more than one path to the information will reduce the number of "Whatever happened to SLAB_DESTROY_BY_RCU?" queries. Thanx, Paul -- 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