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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Wed, 24 Apr 2019 19:56:44 +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 x3OIuhv921626904 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 24 Apr 2019 18:56:43 GMT Received: from b01ledav003.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 9DF12B206A; Wed, 24 Apr 2019 18:56:43 +0000 (GMT) Received: from b01ledav003.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 74192B205F; Wed, 24 Apr 2019 18:56:43 +0000 (GMT) Received: from paulmck-ThinkPad-W541 (unknown [9.80.231.45]) by b01ledav003.gho.pok.ibm.com (Postfix) with ESMTP; Wed, 24 Apr 2019 18:56:43 +0000 (GMT) Received: by paulmck-ThinkPad-W541 (Postfix, from userid 1000) id E4FDA16C2664; Wed, 24 Apr 2019 11:56:42 -0700 (PDT) Date: Wed, 24 Apr 2019 11:56:42 -0700 From: "Paul E. McKenney" To: Oleg Nesterov Cc: Peter Zijlstra , linux-kernel@vger.kernel.org Subject: Re: [PATCH] rcu/sync: kill rcu_sync_type/gp_type Reply-To: paulmck@linux.ibm.com References: <20190423120724.GA6132@redhat.com> <20190423193306.GU3923@linux.ibm.com> <20190424113704.GB16167@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190424113704.GB16167@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-GCONF: 00 x-cbid: 19042418-2213-0000-0000-0000037F4456 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00010988; HX=3.00000242; KW=3.00000007; PH=3.00000004; SC=3.00000285; SDB=6.01193820; UDB=6.00625857; IPR=6.00974644; MB=3.00026579; MTD=3.00000008; XFM=3.00000015; UTC=2019-04-24 18:56:46 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19042418-2214-0000-0000-00005E277F72 Message-Id: <20190424185642.GS3923@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-04-24_12:,, 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-1904240136 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Apr 24, 2019 at 01:37:04PM +0200, Oleg Nesterov wrote: > On 04/23, Paul E. McKenney wrote: > > > > I wordsmithed the commit log and merged in the RCU-bh and RCU checks > > to rcu_sync_is_idle(), with the result shown below. Does that work > > OK, or did I mess something up? > > Yes, thanks! > > the additional RCU-bh and RCU checks matches the "or introduce rcu_read_lock_any_held()" > note from the changelog, perhaps it makes some sense... > > Just one nit below, > > > - * Must be invoked within an RCU read-side critical section whose > > - * flavor matches that of the rcu_sync struture. > > + * Must be invoked within an RCU-sched read-side critical section. > ^^^^^^^^^ > > Given that the actual code: > > > static inline bool rcu_sync_is_idle(struct rcu_sync *rsp) > > { > > -#ifdef CONFIG_PROVE_RCU > > - rcu_sync_lockdep_assert(rsp); > > -#endif > > + RCU_LOCKDEP_WARN(!rcu_read_lock_held() && > > + !rcu_read_lock_bh_held() && > > + !rcu_read_lock_sched_held(), > > + "suspicious rcu_sync_is_idle() usage"); > > does RCU_LOCKDEP_WARN(!rcu_read_lock_any()) the comment should say > > Must be invoked within an RCU read-side critical section of > any flavor Good catch, thank you! I went with this: * Must be invoked within some flavor of RCU read-side critical section. Does that work for you? Thanx, Paul