On Wed, Jan 24, 2018 at 07:31:38PM +0000, Patrick Bellasi wrote: > > > > + /* > > > + * These are the main cases covered: > > > + * - if *p is the only task sleeping on this CPU, then: > > > + * cpu_util (== task_util) > util_est (== 0) > > > + * and thus we return: > > > + * cpu_util_wake = (cpu_util - task_util) = 0 > > > + * > > > + * - if other tasks are SLEEPING on the same CPU, which is just > > > waking > > > + * up, then: > > > + * cpu_util >= task_util > > > + * cpu_util > util_est (== 0) > > > + * and thus we discount *p's blocked utilization to return: > > > + * cpu_util_wake = (cpu_util - task_util) >= 0 > > > + * > > > + * - if other tasks are RUNNABLE on that CPU and > > > + * util_est > cpu_util > > > + * then we use util_est since it returns a more restrictive > > > + * estimation of the spare capacity on that CPU, by just > > > considering > > > + * the expected utilization of tasks already runnable on that > > > CPU. > > > + */ > > > + util_est = cpu_rq(cpu)->cfs.util_est_runnable; > > > + util = max(util, util_est); > > > + > > > + return util; > > I should instead clamp util before returning it! ;-) > > > May be a separate patch to remove the clamping part? > > No, I think we should keep cpu_util_wake clamped to not affect the existing > call sites. I just need to remove it where not needed (done) and add it where > needed (will do on the next iteration).
cpu_util_wake() is called only from capacity_spare_wake(). There are no other callsites. The capacity_spare_wake() is clamping the return value of cpu_util_wake() to CPU capacity. The clamping is not needed, I think. -- Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc. Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.
