From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 1BDB227781E; Tue, 12 Aug 2025 19:12:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755025942; cv=none; b=vEy4S9L6oUqDOT0dwa2UtSNoUPETf8cbogfYtnEN4xMMyJnU9hXxkzz5xdqXtwX2zzoWXXyYoOZVlvPOBE6oOg1tttI8OC4ea7sM0Y94Yt8pfvoN922F4CNo3092iOvzObTK+yH0hLl4xtLckvxuXt6F8qGu4D9LYFpXb77ljsw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755025942; c=relaxed/simple; bh=ojJTAalpvEqDIPNKya+2wPnJGeK0vOMYhgcMpANK+pg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=PcXkYPpOb0Zx7wq1YIidXMzefrTQR2YbE0xjuV9OLxlAuMols0LFilXVA+MXrrtS+dO9LsyLHAGEvsHw18gvF1S9U4ynw2M1Imew4sodbaB3MupL9RZQNsKybbzmhWoDTcUkSFcWbcvtWF/KCxS+snJsJ1MwGyy8gRDg9rWp5Lc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=g5MtMhrj; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="g5MtMhrj" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7FED2C4CEF0; Tue, 12 Aug 2025 19:12:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1755025942; bh=ojJTAalpvEqDIPNKya+2wPnJGeK0vOMYhgcMpANK+pg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=g5MtMhrjRmEFyMNDjr0LLE5GHiVQyqfwq1OBqN8JAhXOwhi4WslwtTGWsa8/Rck5A W8gJzpBIF3Lcmtak6aKz9feCY2iYqCooc5heqGwPL9odkUerK/gAXKjr2mMVkk1ar6 gkJCNqQ4gC3QzgqY3eAKVp33/ULxnEiPOIfy/Xx8= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Marcel Ziswiler , Juri Lelli , "Peter Zijlstra (Intel)" , Waiman Long , Sasha Levin Subject: [PATCH 6.15 157/480] sched/deadline: Initialize dl_servers after SMP Date: Tue, 12 Aug 2025 19:46:05 +0200 Message-ID: <20250812174403.995964601@linuxfoundation.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250812174357.281828096@linuxfoundation.org> References: <20250812174357.281828096@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Juri Lelli [ Upstream commit 9f239df55546ee1d28f0976130136ffd1cad0fd7 ] dl-servers are currently initialized too early at boot when CPUs are not fully up (only boot CPU is). This results in miscalculation of per runqueue DEADLINE variables like extra_bw (which needs a stable CPU count). Move initialization of dl-servers later on after SMP has been initialized and CPUs are all online, so that CPU count is stable and DEADLINE variables can be computed correctly. Fixes: d741f297bceaf ("sched/fair: Fair server interface") Reported-by: Marcel Ziswiler Signed-off-by: Juri Lelli Signed-off-by: Peter Zijlstra (Intel) Acked-by: Waiman Long Tested-by: Marcel Ziswiler # nuc & rock5b Link: https://lore.kernel.org/r/20250627115118.438797-2-juri.lelli@redhat.com Signed-off-by: Sasha Levin --- kernel/sched/core.c | 2 ++ kernel/sched/deadline.c | 48 +++++++++++++++++++++++++---------------- kernel/sched/sched.h | 1 + 3 files changed, 33 insertions(+), 18 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 7d5f51e2f761..333743f143aa 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -8501,6 +8501,8 @@ void __init sched_init_smp(void) init_sched_rt_class(); init_sched_dl_class(); + sched_init_dl_servers(); + sched_smp_initialized = true; } diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index 094134c9b135..ef5b5c045769 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -824,6 +824,8 @@ static inline void setup_new_dl_entity(struct sched_dl_entity *dl_se) struct dl_rq *dl_rq = dl_rq_of_se(dl_se); struct rq *rq = rq_of_dl_rq(dl_rq); + update_rq_clock(rq); + WARN_ON(is_dl_boosted(dl_se)); WARN_ON(dl_time_before(rq_clock(rq), dl_se->deadline)); @@ -1652,23 +1654,7 @@ void dl_server_start(struct sched_dl_entity *dl_se) { struct rq *rq = dl_se->rq; - /* - * XXX: the apply do not work fine at the init phase for the - * fair server because things are not yet set. We need to improve - * this before getting generic. - */ - if (!dl_server(dl_se)) { - u64 runtime = 50 * NSEC_PER_MSEC; - u64 period = 1000 * NSEC_PER_MSEC; - - dl_server_apply_params(dl_se, runtime, period, 1); - - dl_se->dl_server = 1; - dl_se->dl_defer = 1; - setup_new_dl_entity(dl_se); - } - - if (!dl_se->dl_runtime || dl_se->dl_server_active) + if (!dl_server(dl_se) || dl_se->dl_server_active) return; dl_se->dl_server_active = 1; @@ -1679,7 +1665,7 @@ void dl_server_start(struct sched_dl_entity *dl_se) void dl_server_stop(struct sched_dl_entity *dl_se) { - if (!dl_se->dl_runtime) + if (!dl_server(dl_se) || !dl_server_active(dl_se)) return; dequeue_dl_entity(dl_se, DEQUEUE_SLEEP); @@ -1712,6 +1698,32 @@ void dl_server_init(struct sched_dl_entity *dl_se, struct rq *rq, dl_se->server_pick_task = pick_task; } +void sched_init_dl_servers(void) +{ + int cpu; + struct rq *rq; + struct sched_dl_entity *dl_se; + + for_each_online_cpu(cpu) { + u64 runtime = 50 * NSEC_PER_MSEC; + u64 period = 1000 * NSEC_PER_MSEC; + + rq = cpu_rq(cpu); + + guard(rq_lock_irq)(rq); + + dl_se = &rq->fair_server; + + WARN_ON(dl_server(dl_se)); + + dl_server_apply_params(dl_se, runtime, period, 1); + + dl_se->dl_server = 1; + dl_se->dl_defer = 1; + setup_new_dl_entity(dl_se); + } +} + void __dl_server_attach_root(struct sched_dl_entity *dl_se, struct rq *rq) { u64 new_bw = dl_se->dl_bw; diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index d6f82833f652..063f29a228ad 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -384,6 +384,7 @@ extern void dl_server_stop(struct sched_dl_entity *dl_se); extern void dl_server_init(struct sched_dl_entity *dl_se, struct rq *rq, dl_server_has_tasks_f has_tasks, dl_server_pick_f pick_task); +extern void sched_init_dl_servers(void); extern void dl_server_update_idle_time(struct rq *rq, struct task_struct *p); -- 2.39.5