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 X-Spam-Level: X-Spam-Status: No, score=-12.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 62724C4363A for ; Thu, 8 Oct 2020 03:53:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1E3702085B for ; Thu, 8 Oct 2020 03:53:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728218AbgJHDwl (ORCPT ); Wed, 7 Oct 2020 23:52:41 -0400 Received: from out30-45.freemail.mail.aliyun.com ([115.124.30.45]:56938 "EHLO out30-45.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727663AbgJHDwk (ORCPT ); Wed, 7 Oct 2020 23:52:40 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R531e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e01424;MF=baolin.wang@linux.alibaba.com;NM=1;PH=DS;RN=7;SR=0;TI=SMTPD_---0UBGPAZe_1602129158; Received: from localhost(mailfrom:baolin.wang@linux.alibaba.com fp:SMTPD_---0UBGPAZe_1602129158) by smtp.aliyun-inc.com(127.0.0.1); Thu, 08 Oct 2020 11:52:38 +0800 From: Baolin Wang To: tj@kernel.org, axboe@kernel.dk Cc: baolin.wang@linux.alibaba.com, baolin.wang7@gmail.com, linux-block@vger.kernel.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2 2/8] blk-throttle: Avoid getting the current time if tg->last_finish_time is 0 Date: Thu, 8 Oct 2020 11:52:23 +0800 Message-Id: <69cee051a3af94042c9479c39439fab38864e8b2.1602128837.git.baolin.wang@linux.alibaba.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: References: In-Reply-To: References: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org We only update the tg->last_finish_time when the low limitaion is enabled, so we can move the tg->last_finish_time validation a little forward to avoid getting the unnecessary current time stamp if the the low limitation is not enabled. Signed-off-by: Baolin Wang --- block/blk-throttle.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/block/blk-throttle.c b/block/blk-throttle.c index 4007b26..7e72102 100644 --- a/block/blk-throttle.c +++ b/block/blk-throttle.c @@ -2077,10 +2077,14 @@ static void throtl_downgrade_check(struct throtl_grp *tg) static void blk_throtl_update_idletime(struct throtl_grp *tg) { - unsigned long now = ktime_get_ns() >> 10; + unsigned long now; unsigned long last_finish_time = tg->last_finish_time; - if (now <= last_finish_time || last_finish_time == 0 || + if (last_finish_time == 0) + return; + + now = ktime_get_ns() >> 10; + if (now <= last_finish_time || last_finish_time == tg->checked_last_finish_time) return; -- 1.8.3.1