diff options
| author | Dietmar Eggemann <dietmar.eggemann@arm.com> | 2026-03-16 02:36:22 +0300 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2026-03-18 11:06:49 +0300 |
| commit | 8ca12326f592f7554acf2788ecb1c5c954dcf31c (patch) | |
| tree | 09a00811fb07f548c4bccc6eeeb43831f326dddc | |
| parent | f494bfb04615119f31dbd3222c9d39fea3817d40 (diff) | |
| download | linux-8ca12326f592f7554acf2788ecb1c5c954dcf31c.tar.xz | |
PM: EM: Switch to rcu_dereference_all() in wakeup path
em_cpu_energy() is part of the EAS (Fair) task wakeup path. Now that
rcu_read_{,un}lock() have been removed from find_energy_efficient_cpu()
switch to rcu_dereference_all() and check for rcu_read_lock_any_held()
in em_cpu_energy() as well.
In EAS (Fair) task wakeup path is a preempt/IRQ disabled region, so
rcu_read_{,un}lock() can be removed.
Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: K Prateek Nayak <kprateek.nayak@amd.com>
Link: https://patch.msgid.link/5b1228b7-5949-4a45-9f62-e8ce936de694@arm.com
| -rw-r--r-- | include/linux/energy_model.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/include/linux/energy_model.h b/include/linux/energy_model.h index e7497f804644..c909a8ba22e8 100644 --- a/include/linux/energy_model.h +++ b/include/linux/energy_model.h @@ -248,7 +248,7 @@ static inline unsigned long em_cpu_energy(struct em_perf_domain *pd, struct em_perf_state *ps; int i; - WARN_ONCE(!rcu_read_lock_held(), "EM: rcu read lock needed\n"); + lockdep_assert(rcu_read_lock_any_held()); if (!sum_util) return 0; @@ -267,7 +267,7 @@ static inline unsigned long em_cpu_energy(struct em_perf_domain *pd, * Find the lowest performance state of the Energy Model above the * requested performance. */ - em_table = rcu_dereference(pd->em_table); + em_table = rcu_dereference_all(pd->em_table); i = em_pd_get_efficient_state(em_table->state, pd, max_util); ps = &em_table->state[i]; |