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Mon, 20 Jan 2025 05:07:00 GMT Received: from smtpav07.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 20D4020043; Mon, 20 Jan 2025 05:07:00 +0000 (GMT) Received: from smtpav07.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id C9DFF20040; Mon, 20 Jan 2025 05:06:54 +0000 (GMT) Received: from li-fdfde5cc-27d0-11b2-a85c-e224154bf6d4.ibm.com.com (unknown [9.43.34.171]) by smtpav07.fra02v.mail.ibm.com (Postfix) with ESMTP; Mon, 20 Jan 2025 05:06:54 +0000 (GMT) From: Madadi Vineeth Reddy To: kprateek.nayak@amd.com Cc: bsegall@google.com, dietmar.eggemann@arm.com, gautham.shenoy@amd.com, juri.lelli@redhat.com, linux-kernel@vger.kernel.org, mgorman@suse.de, mingo@redhat.com, peterz@infradead.org, rostedt@goodmis.org, swapnil.sapkal@amd.com, vincent.guittot@linaro.org, vschneid@redhat.com, vineethr@linux.ibm.com Subject: Re: [PATCH] sched/fair: Fix inaccurate h_nr_runnable accounting with delayed dequeue Date: Mon, 20 Jan 2025 10:36:39 +0530 Message-ID: <20250120050639.48966-1-vineethr@linux.ibm.com> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20250117105852.23908-1-kprateek.nayak@amd.com> References: <20250117105852.23908-1-kprateek.nayak@amd.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-GUID: 4atiliwdXmfaI82fOjSJ68glthwN0Cws X-Proofpoint-ORIG-GUID: fIScFLRtuwQiMJ4scxKAYTPrEeBdjEUF X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1057,Hydra:6.0.680,FMLib:17.12.68.34 definitions=2025-01-20_01,2025-01-16_01,2024-11-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 phishscore=0 mlxlogscore=981 priorityscore=1501 bulkscore=0 impostorscore=0 clxscore=1011 mlxscore=0 malwarescore=0 suspectscore=0 adultscore=0 lowpriorityscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.19.0-2411120000 definitions=main-2501200038 Hi Prateek, >A SCHED_WARN_ON() to inspect h_nr_runnable post its update in >dequeue_entities() like below: > > cfs_rq->h_nr_runnable -= h_nr_runnable; > SCHED_WARN_ON(((int) cfs_rq->h_nr_runnable) < 0); > >is consistently tripped when running wakeup intensive workloads like >hackbench in a cgroup. I observed that the WARN_ON is triggered during the boot process without the patch, and the patch resolves the issue. However, I was unable to trigger the WARN_ON by running hackbench in a cgroup without the patch. Could you please share the specific test scenario or configuration you used to reproduce it? For the boot process scenario: Tested-by: Madadi Vineeth Reddy Thanks, Madadi Vineeth Reddy