From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 168A4C43441 for ; Fri, 16 Nov 2018 07:05:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D67232145D for ; Fri, 16 Nov 2018 07:05:14 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D67232145D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.ibm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389397AbeKPRQU (ORCPT ); Fri, 16 Nov 2018 12:16:20 -0500 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:44416 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727438AbeKPRQU (ORCPT ); Fri, 16 Nov 2018 12:16:20 -0500 Received: from pps.filterd (m0098409.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id wAG74DUf020372 for ; Fri, 16 Nov 2018 02:05:11 -0500 Received: from e16.ny.us.ibm.com (e16.ny.us.ibm.com [129.33.205.206]) by mx0a-001b2d01.pphosted.com with ESMTP id 2nsrassyv9-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Fri, 16 Nov 2018 02:05:11 -0500 Received: from localhost by e16.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 16 Nov 2018 07:05:09 -0000 Received: from b01cxnp23032.gho.pok.ibm.com (9.57.198.27) by e16.ny.us.ibm.com (146.89.104.203) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Fri, 16 Nov 2018 07:05:02 -0000 Received: from b01ledav003.gho.pok.ibm.com (b01ledav003.gho.pok.ibm.com [9.57.199.108]) by b01cxnp23032.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id wAG751VW29425862 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Fri, 16 Nov 2018 07:05:01 GMT Received: from b01ledav003.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 26F04B2066; Fri, 16 Nov 2018 07:05:01 +0000 (GMT) Received: from b01ledav003.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id CE3CDB2064; Fri, 16 Nov 2018 07:05:00 +0000 (GMT) Received: from paulmck-ThinkPad-W541 (unknown [9.85.196.200]) by b01ledav003.gho.pok.ibm.com (Postfix) with ESMTP; Fri, 16 Nov 2018 07:05:00 +0000 (GMT) Received: by paulmck-ThinkPad-W541 (Postfix, from userid 1000) id 2E75416C36E0; Thu, 15 Nov 2018 23:05:00 -0800 (PST) Date: Thu, 15 Nov 2018 23:05:00 -0800 From: "Paul E. McKenney" To: 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, peterz@infradead.org, rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com, fweisbec@gmail.com, oleg@redhat.com, joel@joelfernandes.org, Lance Roy , "Kirill A. Shutemov" , Yang Shi , Matthew Wilcox , Mel Gorman , Jan Kara , Shakeel Butt , linux-mm@kvack.org Subject: Re: [PATCH tip/core/rcu 6/7] mm: Replace spin_is_locked() with lockdep Reply-To: paulmck@linux.ibm.com References: <20181111200421.GA10551@linux.ibm.com> <20181111200443.10772-6-paulmck@linux.ibm.com> <20181115184917.6goqg67hpojfhk42@linux-r8p5> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181115184917.6goqg67hpojfhk42@linux-r8p5> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-GCONF: 00 x-cbid: 18111607-0072-0000-0000-000003C9DAD4 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00010059; HX=3.00000242; KW=3.00000007; PH=3.00000004; SC=3.00000270; SDB=6.01118156; UDB=6.00577118; IPR=6.00898264; MB=3.00024188; MTD=3.00000008; XFM=3.00000015; UTC=2018-11-16 07:05:07 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18111607-0073-0000-0000-00004A2002AD Message-Id: <20181116070500.GV4170@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-11-16_04:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1811160063 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Nov 15, 2018 at 10:49:17AM -0800, Davidlohr Bueso wrote: > On Sun, 11 Nov 2018, Paul E. McKenney wrote: > > >From: Lance Roy > > > >lockdep_assert_held() is better suited to checking locking requirements, > >since it only checks if the current thread holds the lock regardless of > >whether someone else does. This is also a step towards possibly removing > >spin_is_locked(). > > So fyi I'm not crazy about these kind of patches simply because lockdep > is a lot less used out of anything that's not a lab, and we can be missing > potential offenders. There's obviously nothing wrong about what you describe > above perse, just my two cents. Fair point! One countervailing advantage of lockdep is that it is not subject to the false negatives that can happen if someone else happens to be currently holding the lock. But what would you suggest instead? Thanx, Paul