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Mon, 28 Sep 2026 05:39:20 +0000 (GMT) Received: from li-7bb28a4c-2dab-11b2-a85c-887b5c60d769.ibm.com.com (unknown [9.124.213.68]) by smtpav05.fra02v.mail.ibm.com (Postfix) with ESMTP; Mon, 28 Sep 2026 05:39:20 +0000 (GMT) From: Shrikanth Hegde To: linux-kernel@vger.kernel.org, mingo@kernel.org, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, yury.norov@gmail.com, kprateek.nayak@amd.com, iii@linux.ibm.com, corbet@lwn.net, meted@linux.ibm.com, ynorov@nvidia.com Cc: sshegde@linux.ibm.com, tglx@kernel.org, gregkh@linuxfoundation.org, pbonzini@redhat.com, seanjc@google.com, vschneid@redhat.com, huschle@linux.ibm.com, rostedt@goodmis.org, dietmar.eggemann@arm.com, maddy@linux.ibm.com, srikar@linux.ibm.com, hdanton@sina.com, chleroy@kernel.org, vineeth@bitbyteword.org, frederic@kernel.org, arighi@nvidia.com, pauld@redhat.com, christian.loehle@arm.com, tj@kernel.org, tommaso.cucinotta@gmail.com, maz@kernel.org, rafael@kernel.org, rdunlap@infradead.org, kernellwp@gmail.com, linux-doc@vger.kernel.org, jgross@suse.com, virtualization@lists.linux.dev, sunlightlinux@gmail.com Subject: [PATCH v14 09/13] sched/debug: Add migration stats due to non preferred CPUs Date: Mon, 28 Sep 2026 11:07:24 +0530 Message-ID: <20260928053728.797539-10-sshegde@linux.ibm.com> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260928053728.797539-1-sshegde@linux.ibm.com> References: <20260928053728.797539-1-sshegde@linux.ibm.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-Reinject: loops=2 maxloops=12 X-Proofpoint-Spam-Info: AW1haW4tMjYwOTI4MDAyMiBTYWx0ZWRfX/LmzqE4FqoV9 xe25t46F8k3IJ64o291CmOWW2js74hRuJgWeaShsL7Vzzr1tjWXq6dCuFRYjpFOXcNYZiqYQ3FN OEuiO/6xrNR32DAJcznfr9MrMr2fsZQ= X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwOTI4MDAyMiBTYWx0ZWRfX4eflMuDXdZP+ JlPpvEnc1du9viGjZ6eVQ6RnbHka5ei/+EaqFCh/ZIAW8Ow3ZHzyEyYM290Wb2e1GKwwuK0PRYK soSqO0tAne8Xg2wXUouB82imtQ8qlG7dCREAHkZ/YR7Nf0MkO0F4XB61Xk/9/eUOZ/Zxu/Ob0ji 8osadaA3WUc6TuUR+Ojb/SKjYAqAY64IJMSIjXHAgYEgfrjgpicv7LCFW7aO49yMjxGFF7/R0Bm qXOadxWIvmI57pM33eIybSkeTeARYHMVtOJgjOHQBMexHPua7z6Nb4bV55hWfFYB3YGNAFuQdjU jdAORaaVNFTpNcoy1uFOvxJmPfK0426CgDqnesBbfvEClZdUIBTIhvD1kzwnhX0o86onIGIZaGx Cp93hZf4ingTkNeFeMJBxCRhDmVM5+skwIGeFCmdYnIYZRnG9e3d4M3Pr2b02nPT9q6UeB/sSj/ I54yGcLIFt3OC2jjNYQ== X-Proofpoint-GUID: GgSZ01-8kIyjb2w0qsvwxr08zzfd_A6I X-Authority-Analysis: v=2.4 cv=RKcmjIi+ c=1 sm=1 tr=0 ts=6ab9fd99 cx=c_pps a=5BHTudwdYE3Te8bg5FgnPg==:117 a=5BHTudwdYE3Te8bg5FgnPg==:17 a=VdqzKS8jKosA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=iQ6ETzBq9ecOQQE5vZCe:22 a=VnNF1IyMAAAA:8 a=D3ujz_5LJ-5Q2PFxUbYA:9 X-Proofpoint-ORIG-GUID: 6eXNB_Bpai_Um-8gFDzM2RR1ErGdVyfM X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-09-26_05,2026-09-21_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 priorityscore=1501 spamscore=0 bulkscore=0 impostorscore=0 adultscore=0 lowpriorityscore=0 suspectscore=0 malwarescore=0 phishscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2609040000 definitions=main-2609280022 Add a new per-task stat, - nr_migrations_cpu_non_preferred: number of push migrations while the CPU is non-preferred. Since this new stat is per-task, it changes only /proc//sched. It doesn't update /proc/schedstat. Hence increasing the schedstat version is not necessary. Signed-off-by: Shrikanth Hegde --- include/linux/sched.h | 1 + kernel/sched/core.c | 9 +++++++-- kernel/sched/debug.c | 1 + 3 files changed, 9 insertions(+), 2 deletions(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index d7cc77181ef9..48639b0c75d0 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -554,6 +554,7 @@ struct sched_statistics { u64 nr_failed_migrations_running; u64 nr_failed_migrations_hot; u64 nr_forced_migrations; + u64 nr_migrations_cpu_non_preferred; u64 nr_wakeups; u64 nr_wakeups_sync; diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 5049eff58fb7..7465c983e6f6 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -11236,8 +11236,13 @@ static int sched_non_preferred_cpu_push_stop(void *arg) update_rq_clock(rq); context_unsafe_alias(rq); - if (task_rq(p) == rq && task_on_rq_queued(p)) - rq = __migrate_task(rq, &rf, p, cpu); + if (task_rq(p) == rq && task_on_rq_queued(p)) { + struct rq *dest_rq = __migrate_task(rq, &rf, p, cpu); + + if (rq != dest_rq) + schedstat_inc(p->stats.nr_migrations_cpu_non_preferred); + rq = dest_rq; + } rq_unlock(rq, &rf); } diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c index fda10b3fa249..e6a3b516c703 100644 --- a/kernel/sched/debug.c +++ b/kernel/sched/debug.c @@ -1440,6 +1440,7 @@ void proc_sched_show_task(struct task_struct *p, struct pid_namespace *ns, P_SCHEDSTAT(nr_failed_migrations_running); P_SCHEDSTAT(nr_failed_migrations_hot); P_SCHEDSTAT(nr_forced_migrations); + P_SCHEDSTAT(nr_migrations_cpu_non_preferred); P_SCHEDSTAT(nr_wakeups); P_SCHEDSTAT(nr_wakeups_sync); P_SCHEDSTAT(nr_wakeups_migrate); -- 2.52.0