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Wed, 17 Jun 2026 17:43:16 +0000 (GMT) Received: from li-7bb28a4c-2dab-11b2-a85c-887b5c60d769.ibm.com.com (unknown [9.39.28.77]) by smtpav06.fra02v.mail.ibm.com (Postfix) with ESMTP; Wed, 17 Jun 2026 17:43:15 +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 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, mgorman@suse.de, bsegall@google.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 Subject: [PATCH v4 07/20] sched/fair: Select preferred CPU at wakeup when possible Date: Wed, 17 Jun 2026 23:11:26 +0530 Message-ID: <20260617174139.155540-8-sshegde@linux.ibm.com> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260617174139.155540-1-sshegde@linux.ibm.com> References: <20260617174139.155540-1-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: AW1haW4tMjYwNjE3MDE2NiBTYWx0ZWRfX1ejEKp/qKRd4 2mVRpNycKEBTSFmMjTTfIBK1Y44Me/JbBsLcomQQ1z/n08ghZdRxXSwHBcGOrgaOxUdvl5OkVIo aI5/Axyl0/JF+cYD4Te+pkjY0X4oMp4= X-Proofpoint-GUID: X9U1ad3qGZ6uLmK3AvcWv1H2egrq7X_T X-Authority-Analysis: v=2.4 cv=bMgm5v+Z c=1 sm=1 tr=0 ts=6a32dcc0 cx=c_pps a=bLidbwmWQ0KltjZqbj+ezA==:117 a=bLidbwmWQ0KltjZqbj+ezA==:17 a=FelO9ux0wxsA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=U7nrCbtTmkRpXpFmAIza:22 a=VnNF1IyMAAAA:8 a=aa2H8g5P-lxy6MgAFPcA:9 X-Proofpoint-ORIG-GUID: jBbP7xwlSLsn0Hx-UdhqSnUweTG-qjHF X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNjE3MDE2NiBTYWx0ZWRfX2gp0V2+KWOsF emd7cI8yiwDRKjQbLI5zvw0FbST/Ya39tHZ+x8lBY2QVT04oh+a/WePWM09xu0x9qV9LCJVjvMy tn1bp8KJItze5jF+A2ZN4dswkT+EaWug29Cgdd09C+RJWTEMwTB1ujBt0akD2XIQ26nPurGpS7L 7cuF+ZMOWKiEaqmmhTYfKrRDv5zXG9OCeVq6kyfZOmUY0DAMtShRNTItKwLNHQiKP03zBUSAX6E 0WQyE6ldfyYlZhq398vCsf2bWk66U55ug1H+JO8fB+MUtEi8S2/fRvjDnMKf27QysRco3rFh0CN QoUNCx+b1OUDxBSeGl/Cq3WdRlZpOP12Lf4O7NP6xgfU2JiR3b6Z0vn0jCyUAfisF/1tkiHOPes cZo8iT9ciu0zrtJhudbMjtaU9NaI0nqP1SDvJCKmzMQekLHk9OmomcRLrOxv8ZdIqXOViCpICxW 0WAVej6T/O2+8V0o37A== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.125,FMLib:17.12.100.49 definitions=2026-06-17_02,2026-06-17_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 suspectscore=0 impostorscore=0 malwarescore=0 adultscore=0 spamscore=0 bulkscore=0 priorityscore=1501 phishscore=0 clxscore=1015 lowpriorityscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2606170166 Update available_idle_cpu to consider preferred CPUs. This takes care of lot of decisions at wakeup to use only preferred CPUs. There is no need to put those explicit checks everywhere. Signed-off-by: Shrikanth Hegde --- v3->v4: - Drop check in sched_balance_find_dst_cpu kernel/sched/sched.h | 3 +++ 1 file changed, 3 insertions(+) diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 38fd84b0b8f8..f194a5007e3a 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -1434,6 +1434,9 @@ static inline bool available_idle_cpu(int cpu) if (!idle_rq(cpu_rq(cpu))) return 0; + if (!cpu_preferred(cpu)) + return 0; + if (vcpu_is_preempted(cpu)) return 0; -- 2.47.3