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Fri, 4 Oct 2024 07:18:07 GMT Received: from smtpav06.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 56A0720049; Fri, 4 Oct 2024 07:18:07 +0000 (GMT) Received: from smtpav06.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 600CD2004E; Fri, 4 Oct 2024 07:18:04 +0000 (GMT) Received: from linux.ibm.com (unknown [9.124.214.154]) by smtpav06.fra02v.mail.ibm.com (Postfix) with ESMTPS; Fri, 4 Oct 2024 07:18:04 +0000 (GMT) Date: Fri, 4 Oct 2024 12:47:59 +0530 From: Vishal Chourasia To: Mike Galbraith Cc: Benjamin Segall , Peter Zijlstra , linux-kernel@vger.kernel.org, Ingo Molnar , Vincent Guittot , Juri Lelli , Dietmar Eggemann , Steven Rostedt , Mel Gorman , Valentin Schneider , luis.machado@arm.com Subject: Re: sched/fair: Kernel panics in pick_next_entity Message-ID: References: <20240930144157.GH5594@noisy.programming.kicks-ass.net> <55a2acefffb8c99e4234bd18656a75625447c2d0.camel@gmx.de> <2ffbd642407a2bc51a387b6f89e74f0f9c9f85cf.camel@gmx.de> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-TM-AS-GCONF: 00 X-Proofpoint-GUID: oSIEU-SzYdQQyyPJdpzUJCESB82GSDY6 X-Proofpoint-ORIG-GUID: JsPLWGUSH7xmJJFINEoiVVvy6CpgB4UA X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1051,Hydra:6.0.680,FMLib:17.12.62.30 definitions=2024-10-04_05,2024-10-03_01,2024-09-30_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 bulkscore=0 malwarescore=0 adultscore=0 suspectscore=0 priorityscore=1501 mlxlogscore=548 phishscore=0 mlxscore=0 spamscore=0 impostorscore=0 lowpriorityscore=0 clxscore=1015 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.19.0-2409260000 definitions=main-2410040047 On Thu, Oct 03, 2024 at 11:31:06AM +0200, Mike Galbraith wrote: > On Thu, 2024-10-03 at 06:41 +0200, Mike Galbraith wrote: > > On Wed, 2024-10-02 at 15:31 -0700, Benjamin Segall wrote: > > > > Whether dequeue_entity + enqueue_entity is better or worse than > > > requeue_delayed_entity (+break), I really don't know. > > > > Hm, I'd say requeue_delayed_entity() not only fits better, it using > > less lines gives it an extra brownie point. > > Probable not worth any churn or effort, but it is an option. > > sched: Clean up sched_delayed handling in unthrottle_cfs_rq() > > requeue_delayed_entity() achieves and documents in one line what a less > clear preparatory dequeue facilitates over several, so use it instead, > and remove the superfluous comment. > > Signed-off-by: Mike Galbraith Hi Mike, thanks for the patch! I didn't see any warnings or kernel panics in my setup. Tested-by: Vishal Chourasia > --- > kernel/sched/fair.c | 9 +++------ > 1 file changed, 3 insertions(+), 6 deletions(-) > > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -6058,12 +6058,9 @@ void unthrottle_cfs_rq(struct cfs_rq *cf > for_each_sched_entity(se) { > struct cfs_rq *qcfs_rq = cfs_rq_of(se); > > - /* Handle any unfinished DELAY_DEQUEUE business first. */ > - if (se->sched_delayed) { > - int flags = DEQUEUE_SLEEP | DEQUEUE_DELAYED; > - > - dequeue_entity(qcfs_rq, se, flags); > - } else if (se->on_rq) > + if (se->sched_delayed) > + requeue_delayed_entity(se); > + if (se->on_rq) > break; > enqueue_entity(qcfs_rq, se, ENQUEUE_WAKEUP); > >