From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751347AbdASAPx (ORCPT ); Wed, 18 Jan 2017 19:15:53 -0500 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:36197 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751370AbdASAPv (ORCPT ); Wed, 18 Jan 2017 19:15:51 -0500 Date: Wed, 18 Jan 2017 14:17:37 -0800 From: "Paul E. McKenney" To: willy@infradead.org Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, cl@linux.com, penberg@kernel.org, rientjes@google.com, iamjoonsoo.kim@lge.com, akpm@linux-foundation.org Subject: Re: [PATCH RFC] mm: Rename SLAB_DESTROY_BY_RCU to SLAB_TYPESAFE_BY_RCU Reply-To: paulmck@linux.vnet.ibm.com References: <20170118110731.GA15949@linux.vnet.ibm.com> <20170118111201.GB29472@bombadil.infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170118111201.GB29472@bombadil.infradead.org> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-GCONF: 00 X-Content-Scanned: Fidelis XPS MAILER x-cbid: 17011822-0012-0000-0000-00001364400A X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00006458; HX=3.00000240; KW=3.00000007; PH=3.00000004; SC=3.00000199; SDB=6.00809512; UDB=6.00394369; IPR=6.00586869; BA=6.00005072; NDR=6.00000001; ZLA=6.00000005; ZF=6.00000009; ZB=6.00000000; ZP=6.00000000; ZH=6.00000000; ZU=6.00000002; MB=3.00013969; XFM=3.00000011; UTC=2017-01-18 22:29:22 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17011822-0013-0000-0000-00004AA29530 Message-Id: <20170118221737.GP5238@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-01-18_13:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=1 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1612050000 definitions=main-1701180273 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jan 18, 2017 at 03:12:01AM -0800, willy@infradead.org wrote: > On Wed, Jan 18, 2017 at 03:07:32AM -0800, 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. > > > > However, there is a phrase for this, namely "type safety". This commit > > therefore renames SLAB_DESTROY_BY_RCU to SLAB_TYPESAFE_BY_RCU in order > > to avoid future instances of this sort of confusion. > > This is probably the ultimate in bikeshedding, but RCU is not the > thing which is providing the typesafety. Slab is providing the > typesafety in order to help RCU. So would a better name not be > 'SLAB_TYPESAFETY_FOR_RCU', or more succinctly 'SLAB_RCU_TYPESAFE'? Actually, slab is using RCU to provide type safety to those slab users who request it. Thanx, Paul