From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-181.mta0.migadu.com (out-181.mta0.migadu.com [91.218.175.181]) (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 2BA7D3D45D4 for ; Mon, 20 Jul 2026 09:38:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.181 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784540288; cv=none; b=EakqpuVIsPaJhb2U0yKt67QnApGkdBiYWAvrsYsQhwI876iuth5sAQQTfY/RuD/Motb7/i+UQDmVoIDe5v0QVQKS0iIu0d1cDwwJZIh9UlBZ+M6+/u6NQ8kpHwIFIJd6ub+koEiEc5LE6wuxfEOJ3n/jjbSGa7om3xEHKHBCv6U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784540288; c=relaxed/simple; bh=CwcS1rpDH9/zVMo1p/kk3iMOwfOYQpuysnAULIMw0Pc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=uutA7340YlBrIb/BRLsmylzeBl9/woW68uc+leT8Yrq0jryKk5Nee5Ytbbajd1nIMdeccD4vIjVjvuA7ZH3LGhpRbe+9inHtlhfnQvvtBq+mAKtJYp+BcDzoNpWE3m/XArUtxj0tKEC/Dyva4fcfdkXAhLRdYF1FhuzucBJe+6g= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=oFe+Y33Q; arc=none smtp.client-ip=91.218.175.181 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="oFe+Y33Q" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1784540284; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=iu062VwjFJmKb1NYwQO4WuL9MAqm4vzNE/XIfYy4xek=; b=oFe+Y33QSRXyYWUXCA7Oc6uCw1WlmHDohQcWnNoGA/iV2IJN243vtB/Lo49nx5vTumTfBr Kov2ZXHu5FsqFC6x6+865QYbCOfWTDW8x/bHBE3SfSq3jZAlgHJHvx4GmKZPSgoC8jDa6i 8O6GTMeyN6qOZJga5dBgG/R9B6gLbn4= From: Tao Cui To: Jens Axboe Cc: Tejun Heo , Josef Bacik , Omar Sandoval , Bart Van Assche , Yu Kuai , Chaitanya Kulkarni , Hannes Reinecke , Ming Lei , Damien Le Moal , Nilay Shroff , linux-block@vger.kernel.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, cui.tao@linux.dev, cuitao@kylinos.cn Subject: [PATCH 4/4] block/kyber-iosched: flush per-cpu latency buckets over possible CPUs Date: Mon, 20 Jul 2026 17:37:26 +0800 Message-ID: <20260720093726.28965-5-cui.tao@linux.dev> In-Reply-To: <20260720093726.28965-1-cui.tao@linux.dev> References: <20260720093726.28965-1-cui.tao@linux.dev> Precedence: bulk X-Mailing-List: cgroups@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT From: Tao Cui kyber_timer_fn() sums the per-cpu latency histograms with for_each_online_cpu(). A CPU that goes offline mid-interval leaves its bucket un-flushed; the samples are lost from the current decision and re-appear (stale) when the CPU is onlined again. Fixes: 6e25cb01ea20 ("kyber: implement improved heuristics") Signed-off-by: Tao Cui --- block/kyber-iosched.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/block/kyber-iosched.c b/block/kyber-iosched.c index 971818bcdc9d..2ee552ab8135 100644 --- a/block/kyber-iosched.c +++ b/block/kyber-iosched.c @@ -275,7 +275,7 @@ static void kyber_timer_fn(struct timer_list *t) bool bad = false; /* Sum all of the per-cpu latency histograms. */ - for_each_online_cpu(cpu) { + for_each_possible_cpu(cpu) { struct kyber_cpu_latency *cpu_latency; cpu_latency = per_cpu_ptr(kqd->cpu_latency, cpu); -- 2.43.0