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_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=unavailable 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 507FCC07542 for ; Sat, 25 May 2019 15:52:06 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 9B59E20862 for ; Sat, 25 May 2019 15:52:05 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9B59E20862 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.ibm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 45B75t6lt4zDqQn for ; Sun, 26 May 2019 01:52:02 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=none (mailfrom) smtp.mailfrom=linux.vnet.ibm.com (client-ip=148.163.156.1; helo=mx0a-001b2d01.pphosted.com; envelope-from=paulmck@linux.vnet.ibm.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=linux.ibm.com Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 45B74Y20PGzDqNs for ; Sun, 26 May 2019 01:50:46 +1000 (AEST) Received: from pps.filterd (m0098409.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x4PFgHTR140366 for ; Sat, 25 May 2019 11:50:43 -0400 Received: from e12.ny.us.ibm.com (e12.ny.us.ibm.com [129.33.205.202]) by mx0a-001b2d01.pphosted.com with ESMTP id 2sq10pbefq-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Sat, 25 May 2019 11:50:42 -0400 Received: from localhost by e12.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Sat, 25 May 2019 16:50:41 +0100 Received: from b01cxnp23032.gho.pok.ibm.com (9.57.198.27) by e12.ny.us.ibm.com (146.89.104.199) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Sat, 25 May 2019 16:50:35 +0100 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 x4PFoYP633227200 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Sat, 25 May 2019 15:50:34 GMT Received: from b01ledav003.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 6EC8CB206A; Sat, 25 May 2019 15:50:34 +0000 (GMT) Received: from b01ledav003.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 4D0D0B205F; Sat, 25 May 2019 15:50:34 +0000 (GMT) Received: from paulmck-ThinkPad-W541 (unknown [9.80.199.73]) by b01ledav003.gho.pok.ibm.com (Postfix) with ESMTP; Sat, 25 May 2019 15:50:34 +0000 (GMT) Received: by paulmck-ThinkPad-W541 (Postfix, from userid 1000) id 1DB1C16C32DC; Sat, 25 May 2019 08:50:35 -0700 (PDT) Date: Sat, 25 May 2019 08:50:35 -0700 From: "Paul E. McKenney" To: Joel Fernandes Subject: Re: [PATCH RFC 0/5] Remove some notrace RCU APIs References: <20190524234933.5133-1-joel@joelfernandes.org> <20190524232458.4bcf4eb4@gandalf.local.home> <20190525081444.GC197789@google.com> <20190525070826.16f76ee7@gandalf.local.home> <20190525141954.GA176647@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190525141954.GA176647@google.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-GCONF: 00 x-cbid: 19052515-0060-0000-0000-00000347D01F X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00011161; HX=3.00000242; KW=3.00000007; PH=3.00000004; SC=3.00000286; SDB=6.01208442; UDB=6.00634729; IPR=6.00989440; MB=3.00027049; MTD=3.00000008; XFM=3.00000015; UTC=2019-05-25 15:50:40 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19052515-0061-0000-0000-0000497ECEE0 Message-Id: <20190525155035.GE28207@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:, , definitions=2019-05-25_11:, , 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-1905250110 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: paulmck@linux.ibm.com Cc: rcu@vger.kernel.org, Jonathan Corbet , linux-doc@vger.kernel.org, Lai Jiangshan , Josh Triplett , Steven Rostedt , linux-kernel@vger.kernel.org, Miguel Ojeda , Ingo Molnar , Mathieu Desnoyers , kvm-ppc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Sat, May 25, 2019 at 10:19:54AM -0400, Joel Fernandes wrote: > On Sat, May 25, 2019 at 07:08:26AM -0400, Steven Rostedt wrote: > > On Sat, 25 May 2019 04:14:44 -0400 > > Joel Fernandes wrote: > > > > > > I guess the difference between the _raw_notrace and just _raw variants > > > > is that _notrace ones do a rcu_check_sparse(). Don't we want to keep > > > > that check? > > > > > > This is true. > > > > > > Since the users of _raw_notrace are very few, is it worth keeping this API > > > just for sparse checking? The API naming is also confusing. I was expecting > > > _raw_notrace to do fewer checks than _raw, instead of more. Honestly, I just > > > want to nuke _raw_notrace as done in this series and later we can introduce a > > > sparse checking version of _raw if need-be. The other option could be to > > > always do sparse checking for _raw however that used to be the case and got > > > changed in http://lists.infradead.org/pipermail/linux-afs/2016-July/001016.html > > > > What if we just rename _raw to _raw_nocheck, and _raw_notrace to _raw ? > > That would also mean changing 160 usages of _raw to _raw_nocheck in the > kernel :-/. > > The tracing usage of _raw_notrace is only like 2 or 3 users. Can we just call > rcu_check_sparse directly in the calling code for those and eliminate the APIs? > > I wonder what Paul thinks about the matter as well. My thought is that it is likely that a goodly number of the current uses of _raw should really be some form of _check, with lockdep expressions spelled out. Not that working out what exactly those lockdep expressions should be is necessarily a trivial undertaking. ;-) That aside, if we are going to change the name of an API that is used 160 places throughout the tree, we would need to have a pretty good justification. Without such a justification, it will just look like pointless churn to the various developers and maintainers on the receiving end of the patches. Thanx, Paul > thanks, Steven! >