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Sun, 05 Jul 2026 19:34:46 -0700 (PDT) Received: from mi-HP-ProDesk-680-G6-PCI-Microtower-PC.mioffice.cn ([43.224.245.226]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-847f6b96c04sm2870064b3a.22.2026.07.05.19.34.43 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 05 Jul 2026 19:34:46 -0700 (PDT) From: "zhidao su (Xiaomi)" To: mingo@redhat.com, peterz@infradead.org Cc: juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, vschneid@redhat.com, kprateek.nayak@amd.com, jstultz@google.com, linux-kernel@vger.kernel.org, "zhidao su (Xiaomi)" Subject: [PATCH] sched/fair: align proxy wakeup buddy handling with EEVDF Date: Mon, 6 Jul 2026 10:34:40 +0800 Message-ID: <20260706023440.3055519-1-soolaugust@gmail.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Proxy execution still nominates a newly woken task as NEXT_BUDDY before the wakeup path has passed the same policy and EEVDF eligibility gates used by the updated fair scheduler wakeup logic. Move the NEXT_BUDDY nomination later in check_preempt_wakeup_fair() so throttled, already-rescheduled, disabled-preemption, idle-class, and non-normal wakeups return before updating cfs_rq->next. Also clear stale buddy state when PREEMPT_SHORT overrides slice protection. Signed-off-by: zhidao su (Xiaomi) --- kernel/sched/fair.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 1f1c53c7deb2b..6a6cf8019be90 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -8755,10 +8755,6 @@ static void check_preempt_wakeup_fair(struct rq *rq, struct task_struct *p, int if (task_is_throttled(p)) return; - if (sched_feat(NEXT_BUDDY) && !(wake_flags & WF_FORK) && !pse->sched_delayed) { - set_next_buddy(pse); - } - /* * We can come here with TIF_NEED_RESCHED already set from new task * wake up path. @@ -8811,6 +8807,9 @@ static void check_preempt_wakeup_fair(struct rq *rq, struct task_struct *p, int */ do_preempt_short = sched_feat(PREEMPT_SHORT) && (pse->slice < se->slice); + if (sched_feat(NEXT_BUDDY) && !(wake_flags & WF_FORK) && !pse->sched_delayed) + set_next_buddy(pse); + /* * If @p has become the most eligible task, force preemption. */ @@ -8823,8 +8822,10 @@ static void check_preempt_wakeup_fair(struct rq *rq, struct task_struct *p, int return; preempt: - if (do_preempt_short) + if (do_preempt_short) { cancel_protect_slice(se); + clear_buddies(cfs_rq, se); + } resched_curr_lazy(rq); } -- 2.43.0