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,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 129E2C433DF for ; Mon, 8 Jun 2020 23:06:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DA15520774 for ; Mon, 8 Jun 2020 23:06:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591657609; bh=HvvRqZwkh6QFAxuP2/osGSKcmwJD2DscUKII0BRZplw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=kWLQ8pQN7ZOrkWfJrGzTfpYCsAqafZnKrBT86WY1WbTx5jMPEW2TrIrEy6yCon65t Sn1LztgCboPzUQP1r++QfweEcU5Y6BjSLuDSfxXueiIUoarjhLhLCi4A34Ii0N10x5 LPqaY6mn8HxnCwpmYQKV2tmrJqCMpT3aRUrJ/mS0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727070AbgFHXGr (ORCPT ); Mon, 8 Jun 2020 19:06:47 -0400 Received: from mail.kernel.org ([198.145.29.99]:50044 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726993AbgFHXGm (ORCPT ); Mon, 8 Jun 2020 19:06:42 -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 0D46420853; Mon, 8 Jun 2020 23:06:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591657601; bh=HvvRqZwkh6QFAxuP2/osGSKcmwJD2DscUKII0BRZplw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=swwSbdITupFVkO66bA/IrlyzbWeKGZFDEQTNEShqwzkAfRTrR/gE+PiczdQZ15tlb wtfPUv+fJ+2hpfPnXCIFYhHm7L1mh2rFISJ9Woti9x1IUt7edM6d+Y/Pir2PmpQzzI JvZPIrQgyCm+J82hK5sNb3iX/xrVgiDm7LDnwBpM= 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 5.7 027/274] sched/fair: Refill bandwidth before scaling Date: Mon, 8 Jun 2020 19:02:00 -0400 Message-Id: <20200608230607.3361041-27-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200608230607.3361041-1-sashal@kernel.org> References: <20200608230607.3361041-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@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 da3e5b54715b..2ae7e30ccb33 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -5170,6 +5170,8 @@ 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); @@ -5199,8 +5201,6 @@ 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