From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751151AbdAWTgk (ORCPT ); Mon, 23 Jan 2017 14:36:40 -0500 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:48729 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750714AbdAWTgj (ORCPT ); Mon, 23 Jan 2017 14:36:39 -0500 Date: Mon, 23 Jan 2017 11:36:30 -0800 From: "Paul E. McKenney" To: Josh Triplett Cc: linux-kernel@vger.kernel.org, mingo@kernel.org, jiangshanlai@gmail.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@efficios.com, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com, dvhart@linux.intel.com, fweisbec@gmail.com, oleg@redhat.com, bobby.prani@gmail.com Subject: Re: [PATCH v2 tip/core/rcu 08/18] rcu: Remove short-term CPU kicking Reply-To: paulmck@linux.vnet.ibm.com References: <20170118025316.GB2042@linux.vnet.ibm.com> <1484708037-2523-8-git-send-email-paulmck@linux.vnet.ibm.com> <20170121204344.z2yjx6ouenurgduu@x> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170121204344.z2yjx6ouenurgduu@x> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-GCONF: 00 X-Content-Scanned: Fidelis XPS MAILER x-cbid: 17012319-0020-0000-0000-00000B28ABE0 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00006485; HX=3.00000240; KW=3.00000007; PH=3.00000004; SC=3.00000200; SDB=6.00811657; UDB=6.00395749; IPR=6.00589075; BA=6.00005084; NDR=6.00000001; ZLA=6.00000005; ZF=6.00000009; ZB=6.00000000; ZP=6.00000000; ZH=6.00000000; ZU=6.00000002; MB=3.00014017; XFM=3.00000011; UTC=2017-01-23 19:36:35 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17012319-0021-0000-0000-0000597581E0 Message-Id: <20170123193630.GJ28085@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-01-23_15:,, 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=8.0.1-1612050000 definitions=main-1701230253 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Jan 21, 2017 at 12:43:44PM -0800, Josh Triplett wrote: > On Tue, Jan 17, 2017 at 06:53:47PM -0800, Paul E. McKenney wrote: > > Commit 4914950aaa12d ("rcu: Stop treating in-kernel CPU-bound workloads > > Does this commit ID still match what you have in your tree, post-rebase? In light of your earlier email, good question! But this one is still OK because it is already in mainline. Thanx, Paul > > as errors") added a (relatively) short-timeout call to resched_cpu(). > > This was inspired by as issue that was fixed by b7e7ade34e61 ("sched/core: > > Fix remote wakeups"). But given that this issue was fixed, it is time > > for the current commit to remove this call to resched_cpu(). > > > > Reported-by: Byungchul Park > > Signed-off-by: Paul E. McKenney > > Reviewed-by: Josh Triplett > > --- > > kernel/rcu/tree.c | 5 ----- > > 1 file changed, 5 deletions(-) > > > > diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c > > index 0e61b62e3f4a..5a4aaad75e76 100644 > > --- a/kernel/rcu/tree.c > > +++ b/kernel/rcu/tree.c > > @@ -1220,11 +1220,6 @@ static int rcu_implicit_dynticks_qs(struct rcu_data *rdp, > > rdp->rsp->jiffies_resched += 5; /* Re-enable beating. */ > > } > > > > - /* And if it has been a really long time, kick the CPU as well. */ > > - if (ULONG_CMP_GE(jiffies, > > - rdp->rsp->gp_start + 2 * jiffies_till_sched_qs) || > > - ULONG_CMP_GE(jiffies, rdp->rsp->gp_start + jiffies_till_sched_qs)) > > - resched_cpu(rdp->cpu); /* Force CPU into scheduler. */ > > /* > > * If more than halfway to RCU CPU stall-warning time, do > > * a resched_cpu() to try to loosen things up a bit. > > -- > > 2.5.2 > > >