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=-9.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,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 DEA2BC10F01 for ; Wed, 20 Feb 2019 04:09:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id ACFC22147A for ; Wed, 20 Feb 2019 04:09:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=joelfernandes.org header.i=@joelfernandes.org header.b="lVWOTKd9" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730474AbfBTEJQ (ORCPT ); Tue, 19 Feb 2019 23:09:16 -0500 Received: from mail-qk1-f196.google.com ([209.85.222.196]:46583 "EHLO mail-qk1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730434AbfBTEJP (ORCPT ); Tue, 19 Feb 2019 23:09:15 -0500 Received: by mail-qk1-f196.google.com with SMTP id i5so1101223qkd.13 for ; Tue, 19 Feb 2019 20:09:14 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=joelfernandes.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=1LCwpNs6kStjHl/Jni0GcBly3FB3vdem3YheZShTyrE=; b=lVWOTKd9/raYN/WIag7Bel5GABbTDz9ttkxNv2mlSnJbNKkiKemEHn0tY6cccBBNd4 DfPE4BvxLsqITBDWLUZkCuT0GY7w608EqEsvOavdhUMy38rjwX14jTo7af7eoigx3r8M ErNIFjaTFhtXhBwKQfG4ycoNkk82EqNqXiS44= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=1LCwpNs6kStjHl/Jni0GcBly3FB3vdem3YheZShTyrE=; b=HVjaG75ccvCXt4EYOHaVI+zPgjOOn/N6WwpaTkJhuP76NZlRwACeqP3nClypkmdjsO qh+aWiDnMVvQlYlJc4gmUj9G4m/Tth/DmUrwdNQ/m1hdmBQnSKHm1ZmENA743lPCYqHa uZ6DJB93+zbH3hr1NW+RYqJvsmxvG3oq4lAJNYe4P6z4vAHZ+nagr+h0dAOAmQ+2Qn5J zfU4vr6rDPlxGioiEGfQt5YtbfBwU/5qS7BrQyz7mukEzTuaLZzbds/ju//dwW90DfMG NxL1YPTXnWdjWfICjK3ATJpC/hGrpeHVxMy3XYwdvGr6RxidaSmOzTF2bWKucgouYwgK fldg== X-Gm-Message-State: AHQUAuZ95/L+wuhtLy3uNkaOQHBZReGr8FibO5C0Lqu2YoY4JoKUyhxK o5AuEB0z8YcdOjU38QCKuYu6cQ== X-Google-Smtp-Source: AHgI3IbwY+Hl1J+PjDH0lxTjs8spGEw8WHm/dMtZKpAk67KpMyBzVF8xm0sH3p0RyPgxANykAE+dFA== X-Received: by 2002:aed:3f81:: with SMTP id s1mr22594789qth.94.1550635754478; Tue, 19 Feb 2019 20:09:14 -0800 (PST) Received: from joelaf.cam.corp.google.com ([2620:0:1004:1100:cca9:fccc:8667:9bdc]) by smtp.gmail.com with ESMTPSA id s19sm2024593qth.80.2019.02.19.20.09.13 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 19 Feb 2019 20:09:13 -0800 (PST) From: "Joel Fernandes (Google)" To: linux-kernel@vger.kernel.org, rcu@vger.kernel.org Cc: Joel Fernandes , paulmck@linux.ibm.com Subject: [RFC 4/5] sched/toplogy: Use smp_store_release() instead of rcu_assign_pointer Date: Tue, 19 Feb 2019 23:08:26 -0500 Message-Id: <20190220040827.136184-5-joel@joelfernandes.org> X-Mailer: git-send-email 2.21.0.rc0.258.g878e2cd30e-goog In-Reply-To: <20190220040827.136184-1-joel@joelfernandes.org> References: <20190220040827.136184-1-joel@joelfernandes.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: rcu-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: rcu@vger.kernel.org From: Joel Fernandes The scheduler's topology code seems to want to use rcu_assign_pointer() to initialize various pointers for no apparent reason. With a guess that what was needed here is smp_store_release(), I am replacing it with that. This suppresses the new sparse errors caused by an annotation check I added to rcu_assign_pointer(). Let us avoid (ab)using RCU API and be explicit about what we want. Fixes sparse errors: kernel//sched/topology.c:206:1: sparse: warning: symbol 'sched_energy_mutex' was not declared. Should it be static? kernel//sched/topology.c:207:6: sparse: warning: symbol 'sched_energy_update' was not declared. Should it be static? >> kernel//sched/topology.c:378:9: sparse: error: incompatible types in comparison expression (different address spaces) kernel//sched/topology.c:387:9: sparse: error: incompatible types in comparison expression (different address spaces) kernel//sched/topology.c:612:9: sparse: error: incompatible types in comparison expression (different address spaces) kernel//sched/topology.c:615:9: sparse: error: incompatible types in comparison expression (different address spaces) kernel//sched/topology.c:618:9: sparse: error: incompatible types in comparison expression (different address spaces) kernel//sched/topology.c:621:9: sparse: error: incompatible types in comparison expression (different address spaces) Signed-off-by: Joel Fernandes --- kernel/sched/topology.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c index 3f35ba1d8fde..e7a424d8de8e 100644 --- a/kernel/sched/topology.c +++ b/kernel/sched/topology.c @@ -375,7 +375,7 @@ static bool build_perf_domains(const struct cpumask *cpu_map) /* Attach the new list of performance domains to the root domain. */ tmp = rd->pd; - rcu_assign_pointer(rd->pd, pd); + smp_store_release(&rd->pd, pd); if (tmp) call_rcu(&tmp->rcu, destroy_perf_domain_rcu); @@ -384,7 +384,7 @@ static bool build_perf_domains(const struct cpumask *cpu_map) free: free_pd(pd); tmp = rd->pd; - rcu_assign_pointer(rd->pd, NULL); + smp_store_release(&rd->pd, NULL); if (tmp) call_rcu(&tmp->rcu, destroy_perf_domain_rcu); @@ -609,19 +609,19 @@ static void update_top_cache_domain(int cpu) sds = sd->shared; } - rcu_assign_pointer(per_cpu(sd_llc, cpu), sd); + smp_store_release(&per_cpu(sd_llc, cpu), sd); per_cpu(sd_llc_size, cpu) = size; per_cpu(sd_llc_id, cpu) = id; - rcu_assign_pointer(per_cpu(sd_llc_shared, cpu), sds); + smp_store_release(&per_cpu(sd_llc_shared, cpu), sds); sd = lowest_flag_domain(cpu, SD_NUMA); - rcu_assign_pointer(per_cpu(sd_numa, cpu), sd); + smp_store_release(&per_cpu(sd_numa, cpu), sd); sd = highest_flag_domain(cpu, SD_ASYM_PACKING); - rcu_assign_pointer(per_cpu(sd_asym_packing, cpu), sd); + smp_store_release(&per_cpu(sd_asym_packing, cpu), sd); sd = lowest_flag_domain(cpu, SD_ASYM_CPUCAPACITY); - rcu_assign_pointer(per_cpu(sd_asym_cpucapacity, cpu), sd); + smp_store_release(&per_cpu(sd_asym_cpucapacity, cpu), sd); } /* @@ -668,7 +668,7 @@ cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu) rq_attach_root(rq, rd); tmp = rq->sd; - rcu_assign_pointer(rq->sd, sd); + smp_store_release(&rq->sd, sd); dirty_sched_domain_sysctl(cpu); destroy_sched_domains(tmp); -- 2.21.0.rc0.258.g878e2cd30e-goog