From: Sasha Levin <sashal@kernel.org>
To: stable@vger.kernel.org
Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
Lukasz Luba <lukasz.luba@arm.com>,
Christian Loehle <christian.loehle@arm.com>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Sasha Levin <sashal@kernel.org>
Subject: [PATCH 6.12.y 3/4] PM: EM: Move CPU capacity check to em_adjust_new_capacity()
Date: Tue, 21 Oct 2025 15:22:24 -0400 [thread overview]
Message-ID: <20251021192225.2899605-3-sashal@kernel.org> (raw)
In-Reply-To: <20251021192225.2899605-1-sashal@kernel.org>
From: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
[ Upstream commit 3e3ba654d3097e0031f2add215b12ff81c23814e ]
Move the check of the CPU capacity currently stored in the energy model
against the arch_scale_cpu_capacity() value to em_adjust_new_capacity()
so it will be done regardless of where the latter is called from.
This will be useful when a new em_adjust_new_capacity() caller is added
subsequently.
While at it, move the pd local variable declaration in
em_check_capacity_update() into the loop in which it is used.
No intentional functional impact.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
Tested-by: Christian Loehle <christian.loehle@arm.com>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Link: https://patch.msgid.link/7810787.EvYhyI6sBW@rjwysocki.net
Stable-dep-of: 1ebe8f7e7825 ("PM: EM: Fix late boot with holes in CPU topology")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
kernel/power/energy_model.c | 40 ++++++++++++++++---------------------
1 file changed, 17 insertions(+), 23 deletions(-)
diff --git a/kernel/power/energy_model.c b/kernel/power/energy_model.c
index a035b030ff734..2ef0a7d9d8405 100644
--- a/kernel/power/energy_model.c
+++ b/kernel/power/energy_model.c
@@ -722,10 +722,24 @@ static int em_recalc_and_update(struct device *dev, struct em_perf_domain *pd,
* Adjustment of CPU performance values after boot, when all CPUs capacites
* are correctly calculated.
*/
-static void em_adjust_new_capacity(struct device *dev,
+static void em_adjust_new_capacity(unsigned int cpu, struct device *dev,
struct em_perf_domain *pd)
{
+ unsigned long cpu_capacity = arch_scale_cpu_capacity(cpu);
struct em_perf_table *em_table;
+ struct em_perf_state *table;
+ unsigned long em_max_perf;
+
+ rcu_read_lock();
+ table = em_perf_state_from_pd(pd);
+ em_max_perf = table[pd->nr_perf_states - 1].performance;
+ rcu_read_unlock();
+
+ if (em_max_perf == cpu_capacity)
+ return;
+
+ pr_debug("updating cpu%d cpu_cap=%lu old capacity=%lu\n", cpu,
+ cpu_capacity, em_max_perf);
em_table = em_table_dup(pd);
if (!em_table) {
@@ -741,9 +755,6 @@ static void em_adjust_new_capacity(struct device *dev,
static void em_check_capacity_update(void)
{
cpumask_var_t cpu_done_mask;
- struct em_perf_state *table;
- struct em_perf_domain *pd;
- unsigned long cpu_capacity;
int cpu;
if (!zalloc_cpumask_var(&cpu_done_mask, GFP_KERNEL)) {
@@ -754,7 +765,7 @@ static void em_check_capacity_update(void)
/* Check if CPUs capacity has changed than update EM */
for_each_possible_cpu(cpu) {
struct cpufreq_policy *policy;
- unsigned long em_max_perf;
+ struct em_perf_domain *pd;
struct device *dev;
if (cpumask_test_cpu(cpu, cpu_done_mask))
@@ -777,24 +788,7 @@ static void em_check_capacity_update(void)
cpumask_or(cpu_done_mask, cpu_done_mask,
em_span_cpus(pd));
- cpu_capacity = arch_scale_cpu_capacity(cpu);
-
- rcu_read_lock();
- table = em_perf_state_from_pd(pd);
- em_max_perf = table[pd->nr_perf_states - 1].performance;
- rcu_read_unlock();
-
- /*
- * Check if the CPU capacity has been adjusted during boot
- * and trigger the update for new performance values.
- */
- if (em_max_perf == cpu_capacity)
- continue;
-
- pr_debug("updating cpu%d cpu_cap=%lu old capacity=%lu\n",
- cpu, cpu_capacity, em_max_perf);
-
- em_adjust_new_capacity(dev, pd);
+ em_adjust_new_capacity(cpu, dev, pd);
}
free_cpumask_var(cpu_done_mask);
--
2.51.0
next prev parent reply other threads:[~2025-10-21 19:22 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-16 12:51 FAILED: patch "[PATCH] PM: EM: Fix late boot with holes in CPU topology" failed to apply to 6.12-stable tree gregkh
2025-10-21 19:22 ` [PATCH 6.12.y 1/4] PM: EM: Drop unused parameter from em_adjust_new_capacity() Sasha Levin
2025-10-21 19:22 ` [PATCH 6.12.y 2/4] PM: EM: Slightly reduce em_check_capacity_update() overhead Sasha Levin
2025-10-21 19:22 ` Sasha Levin [this message]
2025-10-21 19:22 ` [PATCH 6.12.y 4/4] PM: EM: Fix late boot with holes in CPU topology Sasha Levin
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