From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2C43BC433FE for ; Tue, 21 Dec 2021 02:00:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234523AbhLUCAm (ORCPT ); Mon, 20 Dec 2021 21:00:42 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44882 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233670AbhLUB7r (ORCPT ); Mon, 20 Dec 2021 20:59:47 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5DFDFC06173F; Mon, 20 Dec 2021 17:59:47 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id EA8096134A; Tue, 21 Dec 2021 01:59:46 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9BDFBC36AE9; Tue, 21 Dec 2021 01:59:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1640051986; bh=yDmdNC0HoR1IwjTR1JRCbmCO+bCirtEJeqJxF7ONdbk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZfF0RjYV/Ixo30kfo559Fm2kAa5yxZ0VKTgVSYYO4up9bOKBrZcGIV62RtKdN/Cyk QqL1jADPsB6WWYjAACiDUD4+WwQ9MYS9iPD+F25knnkp1vrCod6ZZT8/IV8oX2VAla hpJDOFLA823ixUedMFzMnr/692R1RrJbK2LFNv54ZXznNydtctm0kDGcu75H+J751Q 2luAG926g4Y5i6gINzX/lPiUF7sZXCUXM9yiSA/mUZT01QgjpFTvsQoGqrdLPSRy61 cpMVn/f9SmqleQesYjZmzlu7XrS12kLqeCTMLM2GzidzeP/R3GFbVr86F7ZSGvSu8k oqtKRDBz9cP0A== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Jens Axboe , Dexuan Cui , Ming Lei , Sasha Levin , linux-block@vger.kernel.org Subject: [PATCH AUTOSEL 5.10 15/19] block: reduce kblockd_mod_delayed_work_on() CPU consumption Date: Mon, 20 Dec 2021 20:59:10 -0500 Message-Id: <20211221015914.116767-15-sashal@kernel.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20211221015914.116767-1-sashal@kernel.org> References: <20211221015914.116767-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Jens Axboe [ Upstream commit cb2ac2912a9ca7d3d26291c511939a41361d2d83 ] Dexuan reports that he's seeing spikes of very heavy CPU utilization when running 24 disks and using the 'none' scheduler. This happens off the sched restart path, because SCSI requires the queue to be restarted async, and hence we're hammering on mod_delayed_work_on() to ensure that the work item gets run appropriately. Avoid hammering on the timer and just use queue_work_on() if no delay has been specified. Reported-and-tested-by: Dexuan Cui Link: https://lore.kernel.org/linux-block/BYAPR21MB1270C598ED214C0490F47400BF719@BYAPR21MB1270.namprd21.prod.outlook.com/ Reviewed-by: Ming Lei Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- block/blk-core.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/block/blk-core.c b/block/blk-core.c index 26664f2a139eb..4f4e286198660 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -1657,6 +1657,8 @@ EXPORT_SYMBOL(kblockd_schedule_work); int kblockd_mod_delayed_work_on(int cpu, struct delayed_work *dwork, unsigned long delay) { + if (!delay) + return queue_work_on(cpu, kblockd_workqueue, &dwork->work); return mod_delayed_work_on(cpu, kblockd_workqueue, dwork, delay); } EXPORT_SYMBOL(kblockd_mod_delayed_work_on); -- 2.34.1