From: Rafael J. Wysocki <[email protected]>
After commit b8bd1581aa61 ("cpufreq: intel_pstate: Rework iowait
boosting to be less aggressive") the handling of the case when
the SCHED_CPUFREQ_IOWAIT flag is set again after a few iterations of
intel_pstate_update_util() is a bit inconsistent, because the
new value of cpu->iowait_boost may be lower than ONE_EIGHTH_FP
if it was set before, but has not dropped down to zero just yet.
Fix that up by ensuring that the new value of cpu->iowait_boost
will always be at least ONE_EIGHTH_FP then.
Fixes: b8bd1581aa61 ("cpufreq: intel_pstate: Rework iowait boosting to be less
aggressive")
Signed-off-by: Rafael J. Wysocki <[email protected]>
---
drivers/cpufreq/intel_pstate.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
Index: linux-pm/drivers/cpufreq/intel_pstate.c
===================================================================
--- linux-pm.orig/drivers/cpufreq/intel_pstate.c
+++ linux-pm/drivers/cpufreq/intel_pstate.c
@@ -1806,7 +1806,7 @@ static void intel_pstate_update_util(str
/* Start over if the CPU may have been idle. */
if (delta_ns > TICK_NSEC) {
cpu->iowait_boost = ONE_EIGHTH_FP;
- } else if (cpu->iowait_boost) {
+ } else if (cpu->iowait_boost >= ONE_EIGHTH_FP) {
cpu->iowait_boost <<= 1;
if (cpu->iowait_boost > int_tofp(1))
cpu->iowait_boost = int_tofp(1);
