(Replying to the reply because for some reason my mail client never got your reply?!) On 14/10/2019 14:29, Vincent Guittot wrote: > On Mon, 14 Oct 2019 at 14:16, Quentin Perret <qperret@xxxxxxxxxx> wrote: >> FWIW we already clear the EAS static key properly (based on the sd >> pointer, not the static key), so this is really only for the >> capacity-aware stuff. >> Ah, right. >> So what happens it you have mutiple root domains ? You might skip >> build_sched_domains() for one of them and end up not setting the static >> key when you should no ? >> >> I suppose an alternative would be to play with static_branch_inc() / >> static_branch_dec() from build_sched_domains() or something along those >> lines. >> Hmph, so I went with the concept that having the key set should mandate having a non-NULL sd_asym_cpucapacity domain, which is why I unset it as soon as one CPU gets attached to a NULL domain. Sadly as you pointed out, this doesn't work if we have another root domain that sees asymmetry. It also kinda sounds broken to have SDs of a root domain that does not see asymmetry (e.g. LITTLEs only) to see that key being set. Maybe what we want is to have a key per root domain? >> Thanks, >> Quentin
