BACKPORT: schedutil: Reset cached freq if it is not in sync with next_freq
'cached_raw_freq' is used to get the next frequency quickly but should
always be in sync with sg_policy->next_freq. There are cases where it is
not and in such cases it should be reset to avoid switching to incorrect
frequencies.
Consider this case for example:
- policy->cur is 1.2 GHz (Max)
- New request comes for 780 MHz and we store that in cached_raw_freq.
- Based on 780 MHz, we calculate the effective frequency as 800 MHz.
- We then decide not to update the frequency as
sugov_up_down_rate_limit() return true.
- Here cached_raw_freq is 780 MHz and sg_policy->next_freq is 1.2 GHz.
- Now if the utilization doesn't change in next request, then the next
target frequency will still be 780 MHz and it will match with
cached_raw_freq and so we will directly return 1.2 GHz instead of 800
MHz.
BACKPORT of upstream commit 07458f6a5171 ("cpufreq: schedutil: Reset
cached_raw_freq when not in sync with next_freq").
This also updates sugov_update_commit() for handling up/down tunables, which
aren't present in mainline.
Change-Id: I70bca2c5dfdb545a0471d1c9e4c5addb30ab5494
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
1 file changed
