From 75da043d8f880bde8616fd81638c4e2cdb186a08 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Tue, 15 Apr 2025 12:00:52 +0200 Subject: [PATCH] cpufreq/sched: Set need_freq_update in ignore_dl_rate_limit() Notice that ignore_dl_rate_limit() need not piggy back on the limits_changed handling to achieve its goal (which is to enforce a frequency update before its due time). Namely, if sugov_should_update_freq() is updated to check sg_policy->need_freq_update and return 'true' if it is set when sg_policy->limits_changed is not set, ignore_dl_rate_limit() may set the former directly instead of setting the latter, so it can avoid hitting the memory barrier in sugov_should_update_freq(). Update the code accordingly. Signed-off-by: Rafael J. Wysocki Reviewed-by: Christian Loehle Link: https://patch.msgid.link/10666429.nUPlyArG6x@rjwysocki.net --- kernel/sched/cpufreq_schedutil.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c index bcab867575bb..816f07f9d30f 100644 --- a/kernel/sched/cpufreq_schedutil.c +++ b/kernel/sched/cpufreq_schedutil.c @@ -95,6 +95,9 @@ static bool sugov_should_update_freq(struct sugov_policy *sg_policy, u64 time) */ smp_mb(); + return true; + } else if (sg_policy->need_freq_update) { + /* ignore_dl_rate_limit() wants a new frequency to be found. */ return true; } @@ -388,7 +391,7 @@ static inline bool sugov_hold_freq(struct sugov_cpu *sg_cpu) { return false; } static inline void ignore_dl_rate_limit(struct sugov_cpu *sg_cpu) { if (cpu_bw_dl(cpu_rq(sg_cpu->cpu)) > sg_cpu->bw_min) - WRITE_ONCE(sg_cpu->sg_policy->limits_changed, true); + sg_cpu->sg_policy->need_freq_update = true; } static inline bool sugov_update_single_common(struct sugov_cpu *sg_cpu, -- 2.49.0