Commit 75da043d authored by Rafael J. Wysocki's avatar Rafael J. Wysocki
Browse files

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: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: default avatarChristian Loehle <christian.loehle@arm.com>
Link: https://patch.msgid.link/10666429.nUPlyArG6x@rjwysocki.net
parent 79443a7e

kernel/sched/cpufreq_schedutil.c

+4 −1
Original line number Diff line number Diff line
@@ -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,