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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 135C4C433E0 for ; Tue, 9 Jun 2020 00:14:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D865720823 for ; Tue, 9 Jun 2020 00:14:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591661683; bh=455i9YpdBs7gqDTT9okDLeK5g807fcJ/fdxIEM9G10w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=O6O9DldGrdhCZVISBSTbTE4PW8IvpannBD0Vle5VS0CgRKZRNIcQvD8PmpHxKL+12 CG33dy+Q6VAyBEneltlTmSs2yLzY69O4yjX7mR6ksJLeMZRmz+02m9WWhEnhToXlXI zWih3H4RIVk8AcxYfHuRRrywNr75z4BX3SlOPm6s= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732049AbgFIAOk (ORCPT ); Mon, 8 Jun 2020 20:14:40 -0400 Received: from mail.kernel.org ([198.145.29.99]:41910 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730741AbgFHXTM (ORCPT ); Mon, 8 Jun 2020 19:19:12 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 7AEF02083E; Mon, 8 Jun 2020 23:19:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591658352; bh=455i9YpdBs7gqDTT9okDLeK5g807fcJ/fdxIEM9G10w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ec5ghmQnfqLQE3dWBNYaKEA+6sEWMYA2Oaqm/OHOI7BuxNxkIfRClAEVJLhHvg7zP 1KwINkn47C8uBYrRjdc6B0fL6GMZBcCnr7t/3meBtCCOzokH/AtdP07LllIwiGC5iU s8Cirq0FoUy6l383FWGkKNsoOZE0NVntWuMw7bnw= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Huaixin Chang , Peter Zijlstra , Ben Segall , Phil Auld , Sasha Levin Subject: [PATCH AUTOSEL 5.4 019/175] sched/fair: Refill bandwidth before scaling Date: Mon, 8 Jun 2020 19:16:12 -0400 Message-Id: <20200608231848.3366970-19-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200608231848.3366970-1-sashal@kernel.org> References: <20200608231848.3366970-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Huaixin Chang [ Upstream commit 5a6d6a6ccb5f48ca8cf7c6d64ff83fd9c7999390 ] In order to prevent possible hardlockup of sched_cfs_period_timer() loop, loop count is introduced to denote whether to scale quota and period or not. However, scale is done between forwarding period timer and refilling cfs bandwidth runtime, which means that period timer is forwarded with old "period" while runtime is refilled with scaled "quota". Move do_sched_cfs_period_timer() before scaling to solve this. Fixes: 2e8e19226398 ("sched/fair: Limit sched_cfs_period_timer() loop to avoid hard lockup") Signed-off-by: Huaixin Chang Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Ben Segall Reviewed-by: Phil Auld Link: https://lkml.kernel.org/r/20200420024421.22442-3-changhuaixin@linux.alibaba.com Signed-off-by: Sasha Levin --- kernel/sched/fair.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 193b6ab74d7f..3116734630c6 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -4942,6 +4942,8 @@ static enum hrtimer_restart sched_cfs_period_timer(struct hrtimer *timer) if (!overrun) break; + idle = do_sched_cfs_period_timer(cfs_b, overrun, flags); + if (++count > 3) { u64 new, old = ktime_to_ns(cfs_b->period); @@ -4971,8 +4973,6 @@ static enum hrtimer_restart sched_cfs_period_timer(struct hrtimer *timer) /* reset count so we don't come right back in here */ count = 0; } - - idle = do_sched_cfs_period_timer(cfs_b, overrun, flags); } if (idle) cfs_b->period_active = 0; -- 2.25.1