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=-17.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT, USER_IN_DEF_DKIM_WL 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 4D039C2D0EC for ; Fri, 10 Apr 2020 22:52:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 15BAC2083E for ; Fri, 10 Apr 2020 22:52:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="YcTgBQBc" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726829AbgDJWwr (ORCPT ); Fri, 10 Apr 2020 18:52:47 -0400 Received: from mail-pj1-f73.google.com ([209.85.216.73]:57720 "EHLO mail-pj1-f73.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726626AbgDJWwr (ORCPT ); Fri, 10 Apr 2020 18:52:47 -0400 Received: by mail-pj1-f73.google.com with SMTP id np3so3260609pjb.7 for ; Fri, 10 Apr 2020 15:52:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=TmIZI9TKT7lpeEk8rdIESevHF4Y3KmeRZOML5Cjbcoo=; b=YcTgBQBc97ZnvmKzuQ1nw5UtfFGflk+DgqC4Sf44g4BgnrJ12h7U5NrA+H3u/TDrsr O8NaSIs/hv66VjYoFwpn9x71IkZ5/uOirTw4EH1sDLX0mzr+h5fCCJ4YU63S6Bf8IuoQ gG/QhhUIFaaqRjuV3MtnN04gOuYn8AmTXVnAYhvAFY4jRv/twYbI+SBNAm4n4g16NFXw cK3du3oFp2ikvUPTXpLxmzPVxOj96eRGFPOZAkGSiyLd+pYoDD1oQcgivHuUBAwqVuCl QqG7HjRStQVfjkon2azhobVAh65pRW79OFov+GEjtVo4K9tUit5+fo7MRBBDhy1Qr72B Galw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=TmIZI9TKT7lpeEk8rdIESevHF4Y3KmeRZOML5Cjbcoo=; b=OdrzPLrAvyhaCQbD2L4ej2x6pOX1zQCXug6Dki7YkLdUbDZ6WhS0p87Ijk4c5j9tAv mZ1lMUdK0kiHM8PA4LL35ZqS2MUHua62opvvle4LQMF212CDk9MiKqAuRoixjjRkpJYi os6iFd8dx/5f2APSdBkqNkOBKHJsrLCGuUsrJPuJHuohPrR+/6KSB94q8H+cKNfeBHR7 18VYmVbO/Ovh7hRhb10ahaCBZ99i692oUbwS0LJeFHNuNVWEeR5g/W4vhMeBUxmHyfOv pnvkmxBjYVj0fiEpVHIrrtYFy4O7s1uqo3EnKTPAF8unYgBOYSvsxgvhdwVpFoTDdY3A XHLA== X-Gm-Message-State: AGi0PuYiLKyUhmfWqo+GXXqKqgmHY/u5uiIMRqy+60oTI53esYt0yHGy f09nMEE1ElmQCtlyd0T4Fos97tIcTN2d X-Google-Smtp-Source: APiQypIQ1zvPjtacOPKpElUEuTgnIhqM2AYaVckwuzP/Cl52UlxYC2mjNrZQ8rRJTZTyD3nUWtVKRZBkMwG4 X-Received: by 2002:a17:90a:1954:: with SMTP id 20mr8315510pjh.106.1586559165180; Fri, 10 Apr 2020 15:52:45 -0700 (PDT) Date: Fri, 10 Apr 2020 15:52:08 -0700 In-Reply-To: <20200410225208.109717-1-joshdon@google.com> Message-Id: <20200410225208.109717-3-joshdon@google.com> Mime-Version: 1.0 References: <20200410225208.109717-1-joshdon@google.com> X-Mailer: git-send-email 2.26.0.110.g2183baf09c-goog Subject: [PATCH 2/2] sched: remove distribute_running from CFS bandwidth From: Josh Don To: Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot Cc: Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Paul Turner , Huaixin Chang , Phil Auld , linux-kernel@vger.kernel.org, Josh Don Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This is mostly a revert of baa9be4ff. The primary use of distribute_running was to determine whether to add throttled entities to the head or the tail of the throttled list. Now that we always add to the tail, we can remove this field. The other use of distribute_running is in the slack_timer, so that we don't start a distribution while one is already running. However, even in the event that this race occurs, it is fine to have two distributions running (especially now that distribute grabs the cfs_b->lock to determine remaining quota before assigning). Signed-off-by: Josh Don --- kernel/sched/fair.c | 13 +------------ kernel/sched/sched.h | 1 - 2 files changed, 1 insertion(+), 13 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 3fb986c52825..24b5e12efb40 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -4930,14 +4930,12 @@ static int do_sched_cfs_period_timer(struct cfs_bandwidth *cfs_b, int overrun, u /* * This check is repeated as we release cfs_b->lock while we unthrottle. */ - while (throttled && cfs_b->runtime > 0 && !cfs_b->distribute_running) { - cfs_b->distribute_running = 1; + while (throttled && cfs_b->runtime > 0) { raw_spin_unlock_irqrestore(&cfs_b->lock, flags); /* we can't nest cfs_b->lock while distributing bandwidth */ distribute_cfs_runtime(cfs_b); raw_spin_lock_irqsave(&cfs_b->lock, flags); - cfs_b->distribute_running = 0; throttled = !list_empty(&cfs_b->throttled_cfs_rq); } @@ -5051,10 +5049,6 @@ static void do_sched_cfs_slack_timer(struct cfs_bandwidth *cfs_b) /* confirm we're still not at a refresh boundary */ raw_spin_lock_irqsave(&cfs_b->lock, flags); cfs_b->slack_started = false; - if (cfs_b->distribute_running) { - raw_spin_unlock_irqrestore(&cfs_b->lock, flags); - return; - } if (runtime_refresh_within(cfs_b, min_bandwidth_expiration)) { raw_spin_unlock_irqrestore(&cfs_b->lock, flags); @@ -5064,9 +5058,6 @@ static void do_sched_cfs_slack_timer(struct cfs_bandwidth *cfs_b) if (cfs_b->quota != RUNTIME_INF && cfs_b->runtime > slice) runtime = cfs_b->runtime; - if (runtime) - cfs_b->distribute_running = 1; - raw_spin_unlock_irqrestore(&cfs_b->lock, flags); if (!runtime) @@ -5075,7 +5066,6 @@ static void do_sched_cfs_slack_timer(struct cfs_bandwidth *cfs_b) distribute_cfs_runtime(cfs_b); raw_spin_lock_irqsave(&cfs_b->lock, flags); - cfs_b->distribute_running = 0; raw_spin_unlock_irqrestore(&cfs_b->lock, flags); } @@ -5217,7 +5207,6 @@ void init_cfs_bandwidth(struct cfs_bandwidth *cfs_b) cfs_b->period_timer.function = sched_cfs_period_timer; hrtimer_init(&cfs_b->slack_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); cfs_b->slack_timer.function = sched_cfs_slack_timer; - cfs_b->distribute_running = 0; cfs_b->slack_started = false; } diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index db3a57675ccf..7198683b2869 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -349,7 +349,6 @@ struct cfs_bandwidth { u8 idle; u8 period_active; - u8 distribute_running; u8 slack_started; struct hrtimer period_timer; struct hrtimer slack_timer; -- 2.26.0.110.g2183baf09c-goog