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Thu, 14 May 2026 15:24:08 +0000 (GMT) Received: from li-7bb28a4c-2dab-11b2-a85c-887b5c60d769.ibm.com.com (unknown [9.124.213.185]) by smtpav01.fra02v.mail.ibm.com (Postfix) with ESMTP; Thu, 14 May 2026 15:24:07 +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 v3 09/20] sched/rt: Select a preferred CPU for wakeup and pulling rt task Date: Thu, 14 May 2026 20:51:53 +0530 Message-ID: <20260514152204.481115-10-sshegde@linux.ibm.com> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20260514152204.481115-1-sshegde@linux.ibm.com> References: <20260514152204.481115-1-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-ORIG-GUID: r-uPNztcsrVTGAGbtMtUb14wg_YPV4q8 X-Proofpoint-GUID: DFMdI8A7NTGI6UMNKH4614DETiddPQow X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNTE0MDE1MyBTYWx0ZWRfX3lekjNnrnIxe oQFDpHwO5c2jveaH3Xyhqhsc9eRQ7RwB2cG9L7AF2FeFdfRekTuS4Mb9f1PxU0625Z8p/Ze2RlF KKLU8sEThEedzrvpzenEFnURQ/c6F2dwF1RPXSnuQsMrczMtM25ryeJdHWsILoVQ9h5D15qbiev B0jkEgBpFFYDL0MDEv4h50iRmHLmoB126jVmcrojnUFwOOa025gVQ4jsjdrd7bQXT3lzwrM5cjF 6vk4lRviaecwna2eD5D7O0SK3GTv665/qsEeRCj0QU+/ZW+yVU31j1AfvmoSr/NnR8bBsAxV9Ye ixL52rVDw5UIxyPrhI4fD+9XqrNLTZo/xtaUxkVDduTgHczabTHJ1yGwPnLEylkSx2mE4BBbmqT bdHgDHSFq/QdTkG3PuWcf59uFZYJLQtkm6Okr4IcWOrlE7gDVnb7j6zKQZFJVMrYtnBao+B5NZ3 OeYaRSp2KXG+pHJggbA== X-Authority-Analysis: v=2.4 cv=P8UKQCAu c=1 sm=1 tr=0 ts=6a05e924 cx=c_pps a=5BHTudwdYE3Te8bg5FgnPg==:117 a=5BHTudwdYE3Te8bg5FgnPg==:17 a=NGcC8JguVDcA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=RzCfie-kr_QcCd8fBx8p:22 a=VnNF1IyMAAAA:8 a=TGOP_VNwvARlp5vGIUEA:9 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.51,FMLib:17.12.100.49 definitions=2026-05-14_03,2026-05-13_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 adultscore=0 priorityscore=1501 phishscore=0 bulkscore=0 clxscore=1015 malwarescore=0 spamscore=0 lowpriorityscore=0 suspectscore=0 impostorscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2605050000 definitions=main-2605140153 For RT class, - During wakeup choose a preferred CPU. - For push_rt framework, limit pushing to preferred CPUs - Pull the rt task only if CPU is preferred. Signed-off-by: Shrikanth Hegde --- kernel/sched/cpupri.c | 1 + kernel/sched/rt.c | 4 ++++ 2 files changed, 5 insertions(+) diff --git a/kernel/sched/cpupri.c b/kernel/sched/cpupri.c index 8f2237e8b484..24eb26ea9a91 100644 --- a/kernel/sched/cpupri.c +++ b/kernel/sched/cpupri.c @@ -103,6 +103,7 @@ static inline int __cpupri_find(struct cpupri *cp, struct task_struct *p, if (lowest_mask) { cpumask_and(lowest_mask, &p->cpus_mask, vec->mask); cpumask_and(lowest_mask, lowest_mask, cpu_active_mask); + cpumask_and(lowest_mask, lowest_mask, cpu_preferred_mask); /* * We have to ensure that we have at least one bit diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c index 4ee8faf01441..62c53f10de24 100644 --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -2262,6 +2262,10 @@ static void pull_rt_task(struct rq *this_rq) if (likely(!rt_overload_count)) return; + /* No point in pulling the load, just to push it next tick again */ + if (!cpu_preferred(this_cpu)) + return; + /* * Match the barrier from rt_set_overloaded; this guarantees that if we * see overloaded we must also see the rto_mask bit. -- 2.47.3