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 3CB2B37C906; Sat, 12 Sep 2026 12:45:35 +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=1789217136; cv=none; b=B1p3so4MSTxFrLa7jOfakZMA0UKKRyy2Gh7/9bbNwV9L/543LyrvEpGV5GdOENIVyvObeUX32DjrTh4zEVi7sxFB266hkkzP415BQlPTLFen4E3+57Pg4KZmAMO3QPvdlGh3YUAT8N3PnC3iGsNskugsdbXhe5KZrbz9NA3zVIg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789217136; c=relaxed/simple; bh=fKExAb/PC6LYad1vW+HLS1aXFnp13TUEedHktHu1dgw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=kFFXG+xVyvWGE0Nl1/AmyJkog77pJ70rCg/X0yqICfCABHuHRXPCQEsVJ0xyP+EwMC9AkMQN7xHz61VnzO6Fq8a8w1OCcRkt09ErDkmhmIV2merXNgkPhpfXSeTyNxKKsfDrVm35A3FwW4RsjhoxiaB4fEoTLCu4Skr7Iw0mCkI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=EnJeJvJT; 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="EnJeJvJT" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0E5D61F000FF; Sat, 12 Sep 2026 12:45:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789217135; bh=fFUH8mTS1dDjWzenJsNpKiwkVnP3y0eUESoyZxQD69w=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=EnJeJvJTLQQfhTrPGK+e1buqnEazKuMd73LJNq9oebFV10PdQ7z6+80SMq5gaO9xe ksfNNt4wdYys9Vq9QOr0e0US9H1i1ajepjmIOE7zk3oqRmkN2vfyqEgVLOTfhopOZe mWjePNSTGTQUGQgg+L0FF2bzBB9c/P/WOryRckrE= 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 6.12 0877/1376] block/blk-iocost: collect per-cpu latency stats over possible CPUs Date: Sat, 12 Sep 2026 08:55:03 +0200 Message-ID: <20260912065627.106184296@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260912065607.535295758@linuxfoundation.org> References: <20260912065607.535295758@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 6.12-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 a5894ec9696e7..61a347f504d73 100644 --- a/block/blk-iocost.c +++ b/block/blk-iocost.c @@ -1603,7 +1603,7 @@ 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