From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 C5BD6396B9D; Sat, 12 Sep 2026 19:56:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789242986; cv=none; b=PIwb0lKeOrLTeDJb3uss/eLeUtburtNkGYUS2b5pE+n6Xxm8Zq21GBqsG9ZkqQP5jHhvC0LJcCN6JBcdFp8HPftf5qlDvuve44zzPGJRbqRfZi5yvAAxgbXLunchCmGq2Yf8LlM2aLLTA0qrdonXKOentZmIsSPcDifU5+x4EW4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789242986; c=relaxed/simple; bh=50Pd5UYUUibFhrHSNFNKuCZtwpTlOpmtnKztJWpVEL8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=oVH73AXO6oUhYsrKcUEdIIrUp0F2RdM6lfZDS1fpdw7DOZrDrShvfPHabADQZHyhTZRYlfsJWCzVn8acTiM+yDw81uMD+Q00GWmMiCM0ti+BWapEfqoRqjsDtKSf1RDgAOrx/RBOuqbMSvvEbObWToInfL+1WYrRtCzg8Yizwpg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=JcUdajDU; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="JcUdajDU" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 18FD41F00898; Sat, 12 Sep 2026 19:56:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789242984; bh=l6IsYFt3D970b36gTmzMfyJyLtSYIxuPwTn6LPmBAHA=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=JcUdajDUeKGzNNhGiRLaBgkao0wWn6UiogKoisOC14KFjACIpt0BHTd7mX//BEkMz l4SKKis8Qk2Gc+lQWCEuCnl8pRl2TLvSZKEOBCQ8dhTsUWDP9LqzSOzZv0au3Db2vC hYQlanE3MTs9dLAFGk3nXFAnvMCqjlVbNFthr47Q= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Tao Cui , Yu Kuai , Jens Axboe , Sasha Levin Subject: [PATCH 5.10 595/798] block/blk-iocost: collect per-cpu latency stats over possible CPUs Date: Sat, 12 Sep 2026 09:03:43 +0200 Message-ID: <20260912065530.763378332@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260912065516.948645775@linuxfoundation.org> References: <20260912065516.948645775@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Tao Cui [ Upstream commit 4e050c5b92c1600415b2cd452583e543036f3d73 ] ioc_lat_stat() walks ioc->pcpu_stat with for_each_online_cpu() to compute missed-ppm and rq_wait deltas. An offlined CPU is skipped, so its delta is dropped from the period and its last_* watermark is not advanced; on re-online the next collection sees a delta spanning the whole offline interval, corrupting the latency/vrate picture. Fixes: 7caa47151ab2 ("blkcg: implement blk-iocost") Signed-off-by: Tao Cui Reviewed-by: Yu Kuai Link: https://patch.msgid.link/20260720093726.28965-4-cui.tao@linux.dev Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- block/blk-iocost.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/block/blk-iocost.c b/block/blk-iocost.c index 6e895fa90602a..98866b3bfc275 100644 --- a/block/blk-iocost.c +++ b/block/blk-iocost.c @@ -1546,7 +1546,7 @@ static void ioc_lat_stat(struct ioc *ioc, u32 *missed_ppm_ar, u32 *rq_wait_pct_p u64 rq_wait_ns = 0; int cpu, rw; - for_each_online_cpu(cpu) { + for_each_possible_cpu(cpu) { struct ioc_pcpu_stat *stat = per_cpu_ptr(ioc->pcpu_stat, cpu); u64 this_rq_wait_ns; -- 2.53.0