From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from m16.mail.163.com (m16.mail.163.com [220.197.31.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 942C72D8370 for ; Thu, 3 Sep 2026 04:12:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=220.197.31.2 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788408776; cv=none; b=WSot3GXsBy4Ig50qdtP0EMeA9s8glCGCtO4kF/uGc21X0P1o8f56LKY+nYTQ8DqwZj/vRf7+TL/C4QcUMuRkaRiK/ONfgjrkOENBdHDNTGJCUt3LcLL7IySvP42CzC9ocxJWkZtYKsoZFc2HHw6iqOOMG/mnQpyErP9jYtaBIOM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788408776; c=relaxed/simple; bh=f5iNqzWGAqJvjMg1sjcp9o4LLk8tqFvXbRKmdZ78/eg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=djNFEkZcHaWjhJeQJYGSusyybQ1Ha5vp3dprgISu2/1Ll2p2S+wjWvQ+x3ULfyayGE3RCKQ4vVtmX3xVHpFNQzz/s/lB/0JnAXjowK/PeKnIvsl9hXQSz05dqMg0f4Vlbnbd+cG2mzgd7Rfdq6h0gMuEzvbs5yY2mE0DhzuKkAM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com; spf=pass smtp.mailfrom=163.com; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b=p9/NOnWI; arc=none smtp.client-ip=220.197.31.2 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=163.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b="p9/NOnWI" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:To:Subject:Date:Message-ID:MIME-Version; bh=// nTbolChuMSeUTz/HtECCtpVHuJHhzWg+WlXu78Cws=; b=p9/NOnWIgeddkNbfFa IRiAFsg0a8l4bMx2fc0n62l4HskdvDZfiNZCo4l3xB4oXkj0ctxbyZPgvBPM+TeS grk0vxZZO1Ijlv+ir11JgpFWefEzbvOH+bInokEBAPXFoe79SoA8cIZQFs+7IGxm ywBxaMxfDpToufvXfZr0+Urq4= Received: from localhost (unknown []) by gzga-smtp-mtada-g1-2 (Coremail) with SMTP id _____wBnEj+O85hqRfUqAQ--.44885S2; Thu, 03 Sep 2026 12:11:59 +0800 (CST) From: Hui Su To: Peter Zijlstra , Ingo Molnar Cc: Juri Lelli , Vincent Guittot , Dietmar Eggemann , K Prateek Nayak , Valentin Schneider , John Stultz , Chen Yu , Tim Chen , linux-kernel@vger.kernel.org, Hui Su Subject: [PATCH v2 2/2] sched/cache: Drive cache task tick from execution context Date: Thu, 3 Sep 2026 12:11:54 +0800 Message-ID: <20260903041154.2479761-3-sh_def@163.com> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260903041154.2479761-1-sh_def@163.com> References: <20260903041154.2479761-1-sh_def@163.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-CM-TRANSID:_____wBnEj+O85hqRfUqAQ--.44885S2 X-Coremail-Antispam: 1Uf129KBjvJXoWxXFyxGw1DWr17XF1fZw4xWFg_yoWrAF18pa yDWa1UJF4UtayjqF18ZrWDA3W3Wwn2ya42gFs5G3yFkr1rKw1FgFy0qa1avF4Yyr10ka42 vr4jkry7Kr4UKw7anT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x0piXyCJUUUUU= X-CM-SenderInfo: xvkbvvri6rljoofrz/xtbC6g-gQGqY84-XgwAA3f Cache-aware scheduling accounts CPU runtime to the mm of the task actually executing. update_se() passes the execution task to account_mm_sched() for this purpose. With proxy execution, however, sched_tick() invokes task_tick() for the scheduling context in rq->donor. task_tick_cache() is currently called from task_tick_fair(), so it is skipped when a fair task executes on behalf of an RT or deadline donor. In that case account_mm_sched() continues to advance runtime accounting for rq->curr, while task_tick_cache() does not advance the corresponding mm scan epoch. Once the epoch becomes stale, account_mm_sched() can invalidate the mm's preferred LLC. Move cache tick handling one level up into sched_tick(), alongside NUMA tick handling, and run it when the execution context is a fair task. Do the same in sched_tick_remote() so full-dynticks CPUs retain cache tick handling after it is removed from task_tick_fair(). Fixes: df0d98475954 ("sched/cache: Introduce infrastructure for cache-aware load balancing") Suggested-by: Tim Chen Signed-off-by: Hui Su --- kernel/sched/core.c | 16 ++++++++++------ kernel/sched/fair.c | 6 ++---- kernel/sched/sched.h | 1 + 3 files changed, 13 insertions(+), 10 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 15fcc218d2fe..dfef97ef8217 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -5795,9 +5795,11 @@ void sched_tick(void) donor->sched_class->task_tick(rq, donor, 0); - if (rq->curr->sched_class == &fair_sched_class && - static_branch_unlikely(&sched_numa_balancing)) - task_tick_numa(rq, rq->curr); + if (rq->curr->sched_class == &fair_sched_class) { + if (static_branch_unlikely(&sched_numa_balancing)) + task_tick_numa(rq, rq->curr); + task_tick_cache(rq, rq->curr); + } if (sched_feat(LATENCY_WARN)) resched_latency = cpu_resched_latency(rq); @@ -5896,9 +5898,11 @@ static void sched_tick_remote(struct work_struct *work) } curr->sched_class->task_tick(rq, curr, 0); - if (curr->sched_class == &fair_sched_class && - static_branch_unlikely(&sched_numa_balancing)) - task_tick_numa(rq, curr); + if (curr->sched_class == &fair_sched_class) { + if (static_branch_unlikely(&sched_numa_balancing)) + task_tick_numa(rq, curr); + task_tick_cache(rq, curr); + } calc_load_nohz_remote(rq); } diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 55f0460e4ae3..f335479ba562 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -1774,7 +1774,7 @@ void account_mm_sched(struct rq *rq, struct task_struct *p, s64 delta_exec) } } -static void task_tick_cache(struct rq *rq, struct task_struct *p) +void task_tick_cache(struct rq *rq, struct task_struct *p) { struct callback_head *work = &p->cache_work; struct mm_struct *mm = p->mm; @@ -1996,7 +1996,7 @@ static inline void account_mm_sched(struct rq *rq, struct task_struct *p, void init_sched_mm(struct task_struct *p) { } -static void task_tick_cache(struct rq *rq, struct task_struct *p) { } +void task_tick_cache(struct rq *rq, struct task_struct *p) { } static inline int get_pref_llc(struct task_struct *p, struct mm_struct *mm) @@ -15042,8 +15042,6 @@ static void task_tick_fair(struct rq *rq, struct task_struct *curr, int queued) if (queued) return; - task_tick_cache(rq, curr); - update_misfit_status(curr, rq); check_update_overutilized_status(task_rq(curr)); diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 4d619f272b15..5d1f5ee47bf1 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -4153,6 +4153,7 @@ void sched_domains_free_llc_id(int cpu); extern void init_sched_mm(struct task_struct *p); void task_tick_numa(struct rq *rq, struct task_struct *p); +void task_tick_cache(struct rq *rq, struct task_struct *p); extern u64 avg_vruntime(struct cfs_rq *cfs_rq); extern int entity_eligible(struct cfs_rq *cfs_rq, struct sched_entity *se); -- 2.54.0