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=-6.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,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 BEB51C43603 for ; Mon, 16 Dec 2019 23:22:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8A3B124672 for ; Mon, 16 Dec 2019 23:22:42 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="cwKMsEjk" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727486AbfLPXWl (ORCPT ); Mon, 16 Dec 2019 18:22:41 -0500 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:55529 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727298AbfLPXWf (ORCPT ); Mon, 16 Dec 2019 18:22:35 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1576538554; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:in-reply-to:in-reply-to:references:references; bh=3lIQuyNoM7ch1vM74t0JR4mawpsi7LJ5G5gSnc+WS24=; b=cwKMsEjkd6fH/GL4lwwEjRR33MvARdjBIOCvXF/Nxmp15FjojWP0ZnjDyNND0zQOTZ7r5s 2XUCAPWHlbUVXtFeQpgPOOEuyoX4Rb6IkKtXOrEDFo4T2f5Q7tbZQoPGKGHf52AewmnZw7 sQtexeFHVzl+aTW6CvFe+lJdk6Ky6z8= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-74-Y_Gbd7kHMCyhmdt9iBbFWw-1; Mon, 16 Dec 2019 18:22:30 -0500 X-MC-Unique: Y_Gbd7kHMCyhmdt9iBbFWw-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 3E9FB800D41; Mon, 16 Dec 2019 23:22:29 +0000 (UTC) Received: from intel-purley-fpgabmp-02.ml3.eng.bos.redhat.com (intel-purley-fpgabmp-02.ml3.eng.bos.redhat.com [10.19.176.206]) by smtp.corp.redhat.com (Postfix) with ESMTP id 8CB4A7C827; Mon, 16 Dec 2019 23:22:28 +0000 (UTC) From: Scott Wood To: Peter Zijlstra , Frederic Weisbecker , Thomas Gleixner , Ingo Molnar Cc: linux-kernel@vger.kernel.org, Scott Wood Subject: [PATCH 4/4] timers/nohz: Update nohz load in remote tick Date: Mon, 16 Dec 2019 18:22:25 -0500 Message-Id: <1576538545-13274-4-git-send-email-swood@redhat.com> In-Reply-To: <1576538545-13274-1-git-send-email-swood@redhat.com> References: <1576538545-13274-1-git-send-email-swood@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Peter Zijlstra The way loadavg is tracked during nohz only pays attention to the load upon entering nohz. This can be particularly noticeable if full nohz is entered while non-idle, and then the cpu goes idle and stays that way for a long time. Use the remote tick to ensure that full nohz cpus report their deltas within a reasonable time. [swood: added changelog and removed recheck of stopped tick] Signed-off-by: Scott Wood --- This patch was provided by Peter in an unsigned email reply -- Peter, can I get a signoff? --- include/linux/sched/nohz.h | 2 ++ kernel/sched/core.c | 4 +++- kernel/sched/loadavg.c | 33 +++++++++++++++++++++++---------- 3 files changed, 28 insertions(+), 11 deletions(-) diff --git a/include/linux/sched/nohz.h b/include/linux/sched/nohz.h index 1abe91ff6e4a..6d67e9a5af6b 100644 --- a/include/linux/sched/nohz.h +++ b/include/linux/sched/nohz.h @@ -15,9 +15,11 @@ static inline void nohz_balance_enter_idle(int cpu) { } #ifdef CONFIG_NO_HZ_COMMON void calc_load_nohz_start(void); +void calc_load_nohz_remote(struct rq *rq); void calc_load_nohz_stop(void); #else static inline void calc_load_nohz_start(void) { } +static inline void calc_load_nohz_remote(struct rq *rq) { } static inline void calc_load_nohz_stop(void) { } #endif /* CONFIG_NO_HZ_COMMON */ diff --git a/kernel/sched/core.c b/kernel/sched/core.c index dfb8ea801700..2e4a505e48af 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -3676,6 +3676,7 @@ static void sched_tick_remote(struct work_struct *work) if (cpu_is_offline(cpu)) goto out_unlock; + curr = rq->curr; update_rq_clock(rq); if (!is_idle_task(curr)) { @@ -3688,10 +3689,11 @@ static void sched_tick_remote(struct work_struct *work) } curr->sched_class->task_tick(rq, curr, 0); + calc_load_nohz_remote(rq); out_unlock: rq_unlock_irq(rq, &rf); - out_requeue: + /* * Run the remote tick once per second (1Hz). This arbitrary * frequency is large enough to avoid overload but short enough diff --git a/kernel/sched/loadavg.c b/kernel/sched/loadavg.c index 28a516575c18..de22da666ac7 100644 --- a/kernel/sched/loadavg.c +++ b/kernel/sched/loadavg.c @@ -231,16 +231,11 @@ static inline int calc_load_read_idx(void) return calc_load_idx & 1; } -void calc_load_nohz_start(void) +static void calc_load_nohz_fold(struct rq *rq) { - struct rq *this_rq = this_rq(); long delta; - /* - * We're going into NO_HZ mode, if there's any pending delta, fold it - * into the pending NO_HZ delta. - */ - delta = calc_load_fold_active(this_rq, 0); + delta = calc_load_fold_active(rq, 0); if (delta) { int idx = calc_load_write_idx(); @@ -248,6 +243,24 @@ void calc_load_nohz_start(void) } } +void calc_load_nohz_start(void) +{ + /* + * We're going into NO_HZ mode, if there's any pending delta, fold it + * into the pending NO_HZ delta. + */ + calc_load_nohz_fold(this_rq()); +} + +/* + * Keep track of the load for NOHZ_FULL, must be called between + * calc_load_nohz_{start,stop}(). + */ +void calc_load_nohz_remote(struct rq *rq) +{ + calc_load_nohz_fold(rq); +} + void calc_load_nohz_stop(void) { struct rq *this_rq = this_rq(); @@ -268,7 +281,7 @@ void calc_load_nohz_stop(void) this_rq->calc_load_update += LOAD_FREQ; } -static long calc_load_nohz_fold(void) +static long calc_load_nohz_read(void) { int idx = calc_load_read_idx(); long delta = 0; @@ -323,7 +336,7 @@ static void calc_global_nohz(void) } #else /* !CONFIG_NO_HZ_COMMON */ -static inline long calc_load_nohz_fold(void) { return 0; } +static inline long calc_load_nohz_read(void) { return 0; } static inline void calc_global_nohz(void) { } #endif /* CONFIG_NO_HZ_COMMON */ @@ -346,7 +359,7 @@ void calc_global_load(unsigned long ticks) /* * Fold the 'old' NO_HZ-delta to include all NO_HZ CPUs. */ - delta = calc_load_nohz_fold(); + delta = calc_load_nohz_read(); if (delta) atomic_long_add(delta, &calc_load_tasks); -- 1.8.3.1