From patchwork Mon May 10 10:20:52 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "gregkh@linuxfoundation.org" X-Patchwork-Id: 433595 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=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_NONE, 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 12F24C4727A for ; Mon, 10 May 2021 11:21:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E455360FDC for ; Mon, 10 May 2021 11:21:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231977AbhEJLWN (ORCPT ); Mon, 10 May 2021 07:22:13 -0400 Received: from mail.kernel.org ([198.145.29.99]:46208 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237227AbhEJLLh (ORCPT ); Mon, 10 May 2021 07:11:37 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id D4D4561923; Mon, 10 May 2021 11:08:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1620644901; bh=46dDPIUcHdAge07sTTt6Ge+ELHpEmttpkPKsRaehUMc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=N+mkNh8V9cbehnVh5n+Gp2qEqApzEiFKmrqSMs52UjQ645VmHw8cED2K7xepVV3Qj uPxgx+WlZ7PYd8EPWQVbDOTpXW0b2Pt+s7mYG8r6Ri18Kpy39xYGnQ55PF7IyeXevQ WOoV4FImnUWLDZBvo+I7hse7WkXIXWjD+wH5eMZM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Peter Zijlstra (Intel)" , Valentin Schneider , Sasha Levin Subject: [PATCH 5.12 263/384] sched,fair: Alternative sched_slice() Date: Mon, 10 May 2021 12:20:52 +0200 Message-Id: <20210510102023.526463927@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210510102014.849075526@linuxfoundation.org> References: <20210510102014.849075526@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Peter Zijlstra [ Upstream commit 0c2de3f054a59f15e01804b75a04355c48de628c ] The current sched_slice() seems to have issues; there's two possible things that could be improved: - the 'nr_running' used for __sched_period() is daft when cgroups are considered. Using the RQ wide h_nr_running seems like a much more consistent number. - (esp) cgroups can slice it real fine, which makes for easy over-scheduling, ensure min_gran is what the name says. Signed-off-by: Peter Zijlstra (Intel) Tested-by: Valentin Schneider Link: https://lkml.kernel.org/r/20210412102001.611897312@infradead.org Signed-off-by: Sasha Levin --- kernel/sched/fair.c | 12 +++++++++++- kernel/sched/features.h | 3 +++ 2 files changed, 14 insertions(+), 1 deletion(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index d89ddacc1148..0eeeeeb66f33 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -682,7 +682,13 @@ static u64 __sched_period(unsigned long nr_running) */ static u64 sched_slice(struct cfs_rq *cfs_rq, struct sched_entity *se) { - u64 slice = __sched_period(cfs_rq->nr_running + !se->on_rq); + unsigned int nr_running = cfs_rq->nr_running; + u64 slice; + + if (sched_feat(ALT_PERIOD)) + nr_running = rq_of(cfs_rq)->cfs.h_nr_running; + + slice = __sched_period(nr_running + !se->on_rq); for_each_sched_entity(se) { struct load_weight *load; @@ -699,6 +705,10 @@ static u64 sched_slice(struct cfs_rq *cfs_rq, struct sched_entity *se) } slice = __calc_delta(slice, se->load.weight, load); } + + if (sched_feat(BASE_SLICE)) + slice = max(slice, (u64)sysctl_sched_min_granularity); + return slice; } diff --git a/kernel/sched/features.h b/kernel/sched/features.h index 1bc2b158fc51..e911111df83a 100644 --- a/kernel/sched/features.h +++ b/kernel/sched/features.h @@ -90,3 +90,6 @@ SCHED_FEAT(WA_BIAS, true) */ SCHED_FEAT(UTIL_EST, true) SCHED_FEAT(UTIL_EST_FASTUP, true) + +SCHED_FEAT(ALT_PERIOD, true) +SCHED_FEAT(BASE_SLICE, true)