From nobody Mon Oct 6 13:35:44 2025 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 79D822D8794 for ; Mon, 21 Jul 2025 13:02:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753102951; cv=none; b=d+VmYqPLULvb2J7FsjHL7ORiXShQ3jRkuTCnwH6lNotV3G1jZT3498Zx8FAr3sXzeu+rWoxBGvN5C9qLjV8FnxXnlFx7fkqUPHzgmiX6DtgxGe1diEjvreZ1U1c0IudbEF1lZuGtvcobKAIrNCHT86jz5OTqqlgp0OBC74DJ5cQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753102951; c=relaxed/simple; bh=p7O/0tY6woieztP42FD4hsku4invp4xGfH9uQ9uMDys=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:To:Cc; b=d7LvbJW7GT89cfHb/4VHozSRNvGqk7Pi/u8URhAdclzvnihi/MACOzUWbScBn9JWyshzL0XDtSyqkA9VZ+stkLfSHCejLNPGP55AaZoDDkiJhxE7/Aro3oOKBH4QFoGg6ikY6jgHxsokCDbToUJwpXa6K/rzeiG1vPmvQZ/sH2I= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=YU7TuIaw; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="YU7TuIaw" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1753102948; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=LXfNKvE2evyn93v5O5aeec0XduUEsctuPU+y+qzVKQw=; b=YU7TuIawDqkvBBtaCO1u+xHxLp1X2KG9+hVMfgPwAIUOOTacWy/LxBLSU9isfxN4KFvkta xY+Mxm0f7/kbDzMAiIex+sAOv0S+Ot5uoL2DG4fgO2VfzGEd9NLolxiDLZ5y3IByMrzSPl CWNGn7zBefqidgGb+SvWxPGrtyD7/x4= Received: from mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-112-9l9dYDnmNv6iS7HIJOj3yA-1; Mon, 21 Jul 2025 09:02:22 -0400 X-MC-Unique: 9l9dYDnmNv6iS7HIJOj3yA-1 X-Mimecast-MFC-AGG-ID: 9l9dYDnmNv6iS7HIJOj3yA_1753102935 Received: from mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.15]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 227FB1955E9D; Mon, 21 Jul 2025 13:02:10 +0000 (UTC) Received: from jlelli-thinkpadt14gen4.remote.csb (unknown [10.44.32.63]) by mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 4284A19560A1; Mon, 21 Jul 2025 13:02:03 +0000 (UTC) From: Juri Lelli Date: Mon, 21 Jul 2025 15:01:42 +0200 Subject: [PATCH] sched/deadline: Always stop dl-server before changing parameters Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20250721-upstream-fix-dlserver-lessaggressive-b4-v1-1-4ebc10c87e40@redhat.com> X-B4-Tracking: v=1; b=H4sIADU6fmgC/x2NQQqDQAxFryJZNzBGRelVpIupE6cBq5LYoSDev aGrz1u8908wVmGDe3WCchGTbXWobxVMr7hmRknOQIG60FONn90O5fjGWb6YFtcLKy5sFnNWHym MzxanLs7UUmrC0IDXdmU3/k/j47p+yOH2AXkAAAA= X-Change-ID: 20250721-upstream-fix-dlserver-lessaggressive-b4-c5af242d3083 To: Ingo Molnar , Peter Zijlstra , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider Cc: linux-kernel@vger.kernel.org, Marcel Ziswiler , Yuri Andriaccio , Juri Lelli X-Developer-Signature: v=1; a=ed25519-sha256; t=1753102922; l=1629; i=juri.lelli@redhat.com; s=20250626; h=from:subject:message-id; bh=p7O/0tY6woieztP42FD4hsku4invp4xGfH9uQ9uMDys=; b=KHmtr75sGyuD+LYLyvQhp7j1zjz9Ff+L4DdEr11gB9IHhthrFqhddexFOOwgfhk5TZ2J0Vnem NeLhONl94zyDQ+xuLRNkK8MYP6/hjLkR4B5C27JOEz5HvwaXHBhEFs+ X-Developer-Key: i=juri.lelli@redhat.com; a=ed25519; pk=kSwf88oiY/PYrNMRL/tjuBPiSGzc+U3bD13Zag6wO5Q= X-Scanned-By: MIMEDefang 3.0 on 10.30.177.15 Commit cccb45d7c4295 ("sched/deadline: Less agressive dl_server handling") reduced dl-server overhead by delaying disabling servers only after there are no fair task around for a whole period, which means that deadline entities are not dequeued right away on a server stop event. However, the delay opens up a window in which a request for changing server parameters can break per-runqueue running_bw tracking, as reported by Yuri. Close the problematic window by unconditionally calling dl_server_stop() before applying the new parameters (ensuring deadline entities go through an actual dequeue). Fixes: cccb45d7c4295 ("sched/deadline: Less agressive dl_server handling") Reported-by: Yuri Andriaccio Signed-off-by: Juri Lelli Reviewed-by: Valentin Schneider --- kernel/sched/debug.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c index 3f06ab84d53f0..02e16b70a7901 100644 --- a/kernel/sched/debug.c +++ b/kernel/sched/debug.c @@ -376,10 +376,8 @@ static ssize_t sched_fair_server_write(struct file *fi= lp, const char __user *ubu return -EINVAL; } =20 - if (rq->cfs.h_nr_queued) { - update_rq_clock(rq); - dl_server_stop(&rq->fair_server); - } + update_rq_clock(rq); + dl_server_stop(&rq->fair_server); =20 retval =3D dl_server_apply_params(&rq->fair_server, runtime, period, 0); if (retval) --- base-commit: ed0272f0675f31642c3d445a596b544de9db405b change-id: 20250721-upstream-fix-dlserver-lessaggressive-b4-c5af242d3083 Best regards, -- =20 Juri Lelli