On Tue, Oct 15, 2024 at 02:32:00PM -0700, Ankur Arora wrote: > Catalin Marinas <catalin.marinas@xxxxxxx> writes: > > I'd say if you want > > something like this, better introduce a new smp_cond_load_timeout() > > API. The above looks like a hack that may only work on arm64 when the > > event stream is enabled. > > I had a preliminary version of smp_cond_load_relaxed_timeout() here: > https://lore.kernel.org/lkml/87edae3a1x.fsf@xxxxxxxxxx/ > > Even with an smp_cond_load_timeout(), we would need to fallback to > something like the above for uarchs without WFxT. Yes, the default/generic implementation would use cpu_relax(). For the arm64 one, some combination of __cmpwait() and __delay() with the fallback to cpu_relax(). -- Catalin
