From patchwork Mon Sep 25 08:11:31 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lukasz Luba X-Patchwork-Id: 726292 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 ACA83CE7A81 for ; Mon, 25 Sep 2023 08:12:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232629AbjIYIMK (ORCPT ); Mon, 25 Sep 2023 04:12:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55324 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232742AbjIYILq (ORCPT ); Mon, 25 Sep 2023 04:11:46 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id E30441A7; Mon, 25 Sep 2023 01:11:39 -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 D7D0DDA7; Mon, 25 Sep 2023 01:12:17 -0700 (PDT) Received: from e129166.arm.com (unknown [10.57.93.139]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 3B8E93F5A1; Mon, 25 Sep 2023 01:11:37 -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, mhiramat@kernel.org, qyousef@layalina.io, wvw@google.com Subject: [PATCH v4 10/18] PM: EM: Add RCU mechanism which safely cleans the old data Date: Mon, 25 Sep 2023 09:11:31 +0100 Message-Id: <20230925081139.1305766-11-lukasz.luba@arm.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20230925081139.1305766-1-lukasz.luba@arm.com> References: <20230925081139.1305766-1-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 | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+) diff --git a/kernel/power/energy_model.c b/kernel/power/energy_model.c index 5b40db38b745..2345837bfd2c 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 +107,32 @@ 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_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); + + /* Don't free default table since it's used by other frameworks. */ + if (tmp != pd->default_table) + 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)