From patchwork Thu Jan 4 17:15:38 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lukasz Luba X-Patchwork-Id: 761031 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 68A782C843; Thu, 4 Jan 2024 17:15:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com 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 0024D1595; Thu, 4 Jan 2024 09:15:58 -0800 (PST) Received: from e129166.arm.com (unknown [10.57.88.128]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 8A9773F64C; Thu, 4 Jan 2024 09:15:09 -0800 (PST) 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 v6 08/23] PM: EM: Introduce runtime modifiable table Date: Thu, 4 Jan 2024 17:15:38 +0000 Message-Id: <20240104171553.2080674-9-lukasz.luba@arm.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20240104171553.2080674-1-lukasz.luba@arm.com> References: <20240104171553.2080674-1-lukasz.luba@arm.com> Precedence: bulk X-Mailing-List: linux-pm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 The new runtime table can be populated with a new power data to better reflect the actual efficiency of the device e.g. CPU. The power can vary over time e.g. due to the SoC temperature change. Higher temperature can increase power values. For longer running scenarios, such as game or camera, when also other devices are used (e.g. GPU, ISP) the CPU power can change. The new EM framework is able to addresses this issue and change the EM data at runtime safely. Signed-off-by: Lukasz Luba --- include/linux/energy_model.h | 12 ++++++++ kernel/power/energy_model.c | 53 ++++++++++++++++++++++++++++++++++++ 2 files changed, 65 insertions(+) diff --git a/include/linux/energy_model.h b/include/linux/energy_model.h index 1dcd1645dde7..8ddf1d8a9581 100644 --- a/include/linux/energy_model.h +++ b/include/linux/energy_model.h @@ -36,9 +36,20 @@ struct em_perf_state { */ #define EM_PERF_STATE_INEFFICIENT BIT(0) +/** + * struct em_perf_table - Performance states table + * @rcu: RCU used for safe access and destruction + * @state: List of performance states, in ascending order + */ +struct em_perf_table { + struct rcu_head rcu; + struct em_perf_state state[]; +}; + /** * struct em_perf_domain - Performance domain * @table: List of performance states, in ascending order + * @em_table: Pointer to the runtime modifiable em_perf_table * @nr_perf_states: Number of performance states * @flags: See "em_perf_domain flags" * @cpus: Cpumask covering the CPUs of the domain. It's here @@ -54,6 +65,7 @@ struct em_perf_state { */ struct em_perf_domain { struct em_perf_state *table; + struct em_perf_table __rcu *em_table; int nr_perf_states; unsigned long flags; unsigned long cpus[]; diff --git a/kernel/power/energy_model.c b/kernel/power/energy_model.c index e7826403ae1d..c03010084208 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); @@ -103,6 +106,31 @@ static void em_debug_create_pd(struct device *dev) {} static void em_debug_remove_pd(struct device *dev) {} #endif +static void em_destroy_table_rcu(struct rcu_head *rp) +{ + struct em_perf_table __rcu *table; + + table = container_of(rp, struct em_perf_table, rcu); + kfree(table); +} + +static void em_free_table(struct em_perf_table __rcu *table) +{ + call_rcu(&table->rcu, em_destroy_table_rcu); +} + +static struct em_perf_table __rcu * +em_allocate_table(struct em_perf_domain *pd) +{ + struct em_perf_table __rcu *table; + int table_size; + + table_size = sizeof(struct em_perf_state) * pd->nr_perf_states; + + table = kzalloc(sizeof(*table) + table_size, GFP_KERNEL); + return table; +} + static int em_compute_costs(struct device *dev, struct em_perf_state *table, struct em_data_callback *cb, int nr_states, unsigned long flags) @@ -153,6 +181,24 @@ static int em_allocate_perf_table(struct em_perf_domain *pd, return 0; } +static int em_create_runtime_table(struct em_perf_domain *pd) +{ + struct em_perf_table __rcu *table; + int table_size; + + table = em_allocate_table(pd); + if (!table) + return -ENOMEM; + + /* Initialize runtime table with existing data */ + table_size = sizeof(struct em_perf_state) * pd->nr_perf_states; + memcpy(table->state, pd->table, table_size); + + rcu_assign_pointer(pd->em_table, table); + + return 0; +} + static int em_create_perf_table(struct device *dev, struct em_perf_domain *pd, struct em_perf_state *table, struct em_data_callback *cb, @@ -245,6 +291,10 @@ static int em_create_pd(struct device *dev, int nr_states, if (ret) goto free_pd_table; + ret = em_create_runtime_table(pd); + if (ret) + goto free_pd_table; + if (_is_cpu_device(dev)) for_each_cpu(cpu, cpus) { cpu_dev = get_cpu_device(cpu); @@ -461,6 +511,9 @@ void em_dev_unregister_perf_domain(struct device *dev) em_debug_remove_pd(dev); kfree(dev->em_pd->table); + + em_free_table(dev->em_pd->em_table); + kfree(dev->em_pd); dev->em_pd = NULL; mutex_unlock(&em_pd_mutex);