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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS 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 660A3C0044C for ; Sun, 4 Nov 2018 00:14:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 24A682082A for ; Sun, 4 Nov 2018 00:14:36 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 24A682082A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=zytor.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728805AbeKDJ0y (ORCPT ); Sun, 4 Nov 2018 04:26:54 -0500 Received: from terminus.zytor.com ([198.137.202.136]:33183 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726727AbeKDJ0y (ORCPT ); Sun, 4 Nov 2018 04:26:54 -0500 Received: from terminus.zytor.com (localhost [127.0.0.1]) by terminus.zytor.com (8.15.2/8.15.2) with ESMTPS id wA40DcJO3851446 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Sat, 3 Nov 2018 17:13:38 -0700 Received: (from tipbot@localhost) by terminus.zytor.com (8.15.2/8.15.2/Submit) id wA40Dcki3851443; Sat, 3 Nov 2018 17:13:38 -0700 Date: Sat, 3 Nov 2018 17:13:38 -0700 X-Authentication-Warning: terminus.zytor.com: tipbot set sender to tipbot@zytor.com using -f From: tip-bot for Valentin Schneider Message-ID: Cc: torvalds@linux-foundation.org, mingo@kernel.org, peterz@infradead.org, linux-kernel@vger.kernel.org, tglx@linutronix.de, hpa@zytor.com, valentin.schneider@arm.com Reply-To: mingo@kernel.org, peterz@infradead.org, torvalds@linux-foundation.org, linux-kernel@vger.kernel.org, hpa@zytor.com, valentin.schneider@arm.com, tglx@linutronix.de In-Reply-To: <1537974727-30788-2-git-send-email-valentin.schneider@arm.com> References: <1537974727-30788-2-git-send-email-valentin.schneider@arm.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:sched/core] sched/fair: Don't increase sd->balance_interval on newidle balance Git-Commit-ID: 3f130a37c442d5c4d66531b240ebe9abfef426b5 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 3f130a37c442d5c4d66531b240ebe9abfef426b5 Gitweb: https://git.kernel.org/tip/3f130a37c442d5c4d66531b240ebe9abfef426b5 Author: Valentin Schneider AuthorDate: Wed, 26 Sep 2018 16:12:07 +0100 Committer: Ingo Molnar CommitDate: Sun, 4 Nov 2018 00:59:23 +0100 sched/fair: Don't increase sd->balance_interval on newidle balance When load_balance() fails to move some load because of task affinity, we end up increasing sd->balance_interval to delay the next periodic balance in the hopes that next time we look, that annoying pinned task(s) will be gone. However, idle_balance() pays no attention to sd->balance_interval, yet it will still lead to an increase in balance_interval in case of pinned tasks. If we're going through several newidle balances (e.g. we have a periodic task), this can lead to a huge increase of the balance_interval in a very small amount of time. To prevent that, don't increase the balance interval when going through a newidle balance. This is a similar approach to what is done in commit 58b26c4c0257 ("sched: Increment cache_nice_tries only on periodic lb"), where we disregard newidle balance and rely on periodic balance for more stable results. Signed-off-by: Valentin Schneider Signed-off-by: Peter Zijlstra (Intel) Cc: Dietmar.Eggemann@arm.com Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: patrick.bellasi@arm.com Cc: vincent.guittot@linaro.org Link: http://lkml.kernel.org/r/1537974727-30788-2-git-send-email-valentin.schneider@arm.com Signed-off-by: Ingo Molnar --- kernel/sched/fair.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 4e298931a715..a17ca4254427 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -8876,13 +8876,22 @@ out_all_pinned: sd->nr_balance_failed = 0; out_one_pinned: + ld_moved = 0; + + /* + * idle_balance() disregards balance intervals, so we could repeatedly + * reach this code, which would lead to balance_interval skyrocketting + * in a short amount of time. Skip the balance_interval increase logic + * to avoid that. + */ + if (env.idle == CPU_NEWLY_IDLE) + goto out; + /* tune up the balancing interval */ if ((env.flags & LBF_ALL_PINNED && sd->balance_interval < MAX_PINNED_INTERVAL) || sd->balance_interval < sd->max_interval) sd->balance_interval *= 2; - - ld_moved = 0; out: return ld_moved; }