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=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,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 56D85C2BA19 for ; Tue, 14 Apr 2020 15:07:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 331FC20768 for ; Tue, 14 Apr 2020 15:07:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2436669AbgDNPHO (ORCPT ); Tue, 14 Apr 2020 11:07:14 -0400 Received: from foss.arm.com ([217.140.110.172]:57662 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729370AbgDNPGq (ORCPT ); Tue, 14 Apr 2020 11:06:46 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id CB45DC14; Tue, 14 Apr 2020 08:06:45 -0700 (PDT) Received: from e107158-lin.cambridge.arm.com (e107158-lin.cambridge.arm.com [10.1.195.21]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id B026F3F73D; Tue, 14 Apr 2020 08:06:43 -0700 (PDT) From: Qais Yousef To: Ingo Molnar , Peter Zijlstra Cc: Qais Yousef , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Andrew Morton , Thomas Gleixner , Yury Norov , Paul Turner , Alexey Dobriyan , Josh Don , Pavan Kondeti , linux-kernel@vger.kernel.org Subject: [PATCH 2/4] cpumask: Make cpumask_any() truly random Date: Tue, 14 Apr 2020 16:05:54 +0100 Message-Id: <20200414150556.10920-3-qais.yousef@arm.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200414150556.10920-1-qais.yousef@arm.com> References: <20200414150556.10920-1-qais.yousef@arm.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit 46a87b3851f0 ("sched/core: Distribute tasks within affinity masks") added a new cpumask_any_and_distribute() which truly returns a random cpu within the mask. Previous patch renamed the function to cpumask_any_and(), so that old users can take advantage of the new randomness behavior. Build up on that, and let cpumask_any() truly random too by re-using the logic from cpumask_any_and(). Signed-off-by: Qais Yousef CC: Juri Lelli CC: Vincent Guittot CC: Dietmar Eggemann CC: Steven Rostedt CC: Ben Segall CC: Mel Gorman CC: Andrew Morton CC: Thomas Gleixner CC: Yury Norov CC: Paul Turner CC: Alexey Dobriyan CC: Josh Don CC: Pavan Kondeti CC: linux-kernel@vger.kernel.org --- include/linux/cpumask.h | 14 ++++++-------- lib/cpumask.c | 24 ++++++++++++++++++++++++ 2 files changed, 30 insertions(+), 8 deletions(-) diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h index e4d6d140a67c..7fb25d256043 100644 --- a/include/linux/cpumask.h +++ b/include/linux/cpumask.h @@ -194,6 +194,11 @@ static inline unsigned int cpumask_local_spread(unsigned int i, int node) return 0; } +static inline int cpumask_any(const struct cpumask *src1p) +{ + return 0; +} + static inline int cpumask_any_and(const struct cpumask *src1p, const struct cpumask *src2p) { @@ -251,6 +256,7 @@ static inline unsigned int cpumask_next_zero(int n, const struct cpumask *srcp) int cpumask_next_and(int n, const struct cpumask *, const struct cpumask *); int cpumask_any_but(const struct cpumask *mask, unsigned int cpu); unsigned int cpumask_local_spread(unsigned int i, int node); +int cpumask_any(const struct cpumask *srcp); int cpumask_any_and(const struct cpumask *src1p, const struct cpumask *src2p); /** @@ -600,14 +606,6 @@ static inline void cpumask_copy(struct cpumask *dstp, bitmap_copy(cpumask_bits(dstp), cpumask_bits(srcp), nr_cpumask_bits); } -/** - * cpumask_any - pick a "random" cpu from *srcp - * @srcp: the input cpumask - * - * Returns >= nr_cpu_ids if no cpus set. - */ -#define cpumask_any(srcp) cpumask_first(srcp) - /** * cpumask_first_and - return the first cpu from *srcp1 & *srcp2 * @src1p: the first input diff --git a/lib/cpumask.c b/lib/cpumask.c index b527a153b023..bcac63e45374 100644 --- a/lib/cpumask.c +++ b/lib/cpumask.c @@ -259,3 +259,27 @@ int cpumask_any_and(const struct cpumask *src1p, const struct cpumask *src2p) return next; } EXPORT_SYMBOL(cpumask_any_and); + +/** + * cpumask_any - pick a "random" cpu from *srcp + * @srcp: the input cpumask + * + * Returns >= nr_cpu_ids if no cpus set. + */ +int cpumask_any(const struct cpumask *srcp) +{ + int next, prev; + + /* NOTE: our first selection will skip 0. */ + prev = __this_cpu_read(distribute_cpu_mask_prev); + + next = cpumask_next(prev, srcp); + if (next >= nr_cpu_ids) + next = cpumask_first(srcp); + + if (next < nr_cpu_ids) + __this_cpu_write(distribute_cpu_mask_prev, next); + + return next; +} +EXPORT_SYMBOL(cpumask_any); -- 2.17.1