On 26-07-17, 22:34, Joel Fernandes (Google) wrote:
On Wed, Jul 26, 2017 at 2:22 AM, Viresh Kumar viresh.kumar@linaro.org wrote:
@@ -221,7 +226,7 @@ static void sugov_update_single(struct update_util_data *hook, u64 time, sugov_set_iowait_boost(sg_cpu, time, flags); sg_cpu->last_update = time;
if (!sugov_should_update_freq(sg_policy, time))
if (!sugov_should_update_freq(sg_policy, time, hook->cpu)) return;
Since with the remote callbacks now possible, isn't it unsafe to modify sg_cpu and sg_policy structures without a lock in sugov_update_single?
Unlike sugov_update_shared, we don't acquire any lock in sugov_update_single before updating these structures. Did I miss something?
As Peter already mentioned it earlier, the callbacks are called with rq locks held and so sugov_update_single() wouldn't get called in parallel for a target CPU.
That's the only race you were worried about ?
-- viresh