From patchwork Fri Jul 21 15:50:19 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lukasz Luba X-Patchwork-Id: 705994 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 95552EB64DD for ; Fri, 21 Jul 2023 15:51:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231199AbjGUPvD (ORCPT ); Fri, 21 Jul 2023 11:51:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50978 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231775AbjGUPut (ORCPT ); Fri, 21 Jul 2023 11:50:49 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 557683C35; Fri, 21 Jul 2023 08:50:28 -0700 (PDT) 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 2998014BF; Fri, 21 Jul 2023 08:51:11 -0700 (PDT) Received: from e129166.arm.com (unknown [10.57.0.79]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 011F43F738; Fri, 21 Jul 2023 08:50:24 -0700 (PDT) From: Lukasz Luba To: linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, rafael@kernel.org Cc: lukasz.luba@arm.com, dietmar.eggemann@arm.com, rui.zhang@intel.com, amit.kucheria@verdurent.com, amit.kachhap@gmail.com, daniel.lezcano@linaro.org, viresh.kumar@linaro.org, len.brown@intel.com, pavel@ucw.cz, Pierre.Gondois@arm.com, ionela.voinescu@arm.com, mhiramat@kernel.org Subject: [PATCH v3 09/12] PM: EM: Add RCU mechanism which safely cleans the old data Date: Fri, 21 Jul 2023 16:50:19 +0100 Message-Id: <20230721155022.2339982-10-lukasz.luba@arm.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20230721155022.2339982-1-lukasz.luba@arm.com> References: <20230721155022.2339982-1-lukasz.luba@arm.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org The EM is going to support runtime modifications of the power data. Introduce RCU safe mechanism to clean up the old allocated EM data. It also adds a mutex for the EM structure to serialize the modifiers. Signed-off-by: Lukasz Luba --- kernel/power/energy_model.c | 42 +++++++++++++++++++++++++++++++++++++ 1 file changed, 42 insertions(+) diff --git a/kernel/power/energy_model.c b/kernel/power/energy_model.c index c2f8a0046f8a..4596bfe7398e 100644 --- a/kernel/power/energy_model.c +++ b/kernel/power/energy_model.c @@ -23,6 +23,9 @@ */ static DEFINE_MUTEX(em_pd_mutex); +static void em_cpufreq_update_efficiencies(struct device *dev, + struct em_perf_state *table); + static bool _is_cpu_device(struct device *dev) { return (dev->bus == &cpu_subsys); @@ -104,6 +107,45 @@ static void em_debug_create_pd(struct device *dev) {} static void em_debug_remove_pd(struct device *dev) {} #endif +static void em_destroy_rt_table_rcu(struct rcu_head *rp) +{ + struct em_perf_table *runtime_table; + + runtime_table = container_of(rp, struct em_perf_table, rcu); + kfree(runtime_table->state); + kfree(runtime_table); +} + +static void em_destroy_tmp_setup_rcu(struct rcu_head *rp) +{ + struct em_perf_table *runtime_table; + + runtime_table = container_of(rp, struct em_perf_table, rcu); + kfree(runtime_table); +} + +static void em_perf_runtime_table_set(struct device *dev, + struct em_perf_table *runtime_table) +{ + struct em_perf_domain *pd = dev->em_pd; + struct em_perf_table *tmp; + + tmp = pd->runtime_table; + + rcu_assign_pointer(pd->runtime_table, runtime_table); + + em_cpufreq_update_efficiencies(dev, runtime_table->state); + + /* + * Check if the 'state' array is not actually the one from setup. + * If it is then don't free it. + */ + if (tmp->state == pd->default_table->state) + call_rcu(&tmp->rcu, em_destroy_tmp_setup_rcu); + else + call_rcu(&tmp->rcu, em_destroy_rt_table_rcu); +} + static int em_compute_costs(struct device *dev, struct em_perf_state *table, struct em_data_callback *cb, int nr_states, unsigned long flags)