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 0AEA433C198; Sat, 12 Sep 2026 10:40:48 +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=1789209650; cv=none; b=EUkCPBvwxgNIS6lQhKhmaIiTRIj/hZmr5AyZSVBIkKE/Xka2s0HXsQ7NAnOQ2/csN6gK/3VyalmMtwBK8cvKTaeChcvTpe9SDJ4aDdlfCKJ0YLF3w4/+0rp/rIYK2mLDmRBeF4fyTjEhKQK9n1lbafOW4X/08f+fuZfjuZ/aBkc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789209650; c=relaxed/simple; bh=WF+OHcBsWiLy0vzaUDSdzK22+4BWAMk2qxSSKuivaQU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=A059yuoIS4tYtEB8ankuH+lH7pO9poLatCgOlt0g2t2woh7Gtn7ok8Ba7fsReU2mTwZlti2NIz5smvZbq4WIYon8/FSpSkF+wJs3KiqQnLCVUQRVH4v4e4dv4emlrifKvlZd2B+CMpf8UKzhOzql5fuSxRqOI0LodMofA0dMIHo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=rjAE2n0O; 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="rjAE2n0O" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 878B81F000FF; Sat, 12 Sep 2026 10:40:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789209648; bh=y2ykYq0e8WFfR89n37+jJ4uWhzsxS53v7xTS5+jTGc0=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=rjAE2n0Oy2pX+4P1E4Ncg0k+vPC94RAe4wQpzm2NQr3vzY6TQ9DuHE5QNxexIxCMl iFHLGfLHq0OodkIsrTdAbXt17mjym7kzgzM/cOZKPXNDihUzPD11omaLOZ6XGXdIRH kM+378DyLUpWMokmB2XgItjRzDHVpF85VHX/a3nY= 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 6.18 0863/1518] block/blk-iocost: collect per-cpu latency stats over possible CPUs Date: Sat, 12 Sep 2026 08:50:32 +0200 Message-ID: <20260912065642.971791123@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260912065623.398859879@linuxfoundation.org> References: <20260912065623.398859879@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 6.18-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 5bfd70311359c..ecf4969125050 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