Messages in this thread | | | From | Lukas Bulwahn <> | Date | Wed, 30 Sep 2020 18:53:37 +0200 (CEST) | Subject | Re: [PATCH -next for tip:x86/pti] x86/tlb: drop unneeded local vars in enable_l1d_flush_for_task() |
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On Wed, 30 Sep 2020, Thomas Gleixner wrote:
> On Tue, Sep 29 2020 at 10:37, Peter Zijlstra wrote: > > Here, I fixed it.. > > Well, no. What Balbir is trying to do here is to establish whether a > task runs on a !SMT core. sched_smt_active() is system wide, but their > setup is to have a bunch of SMT enabled cores and cores where SMT is off > because the sibling is offlined. They affine these processes to non SMT > cores and the check there validates that before it enabled that flush > thingy. > > Of course this is best effort voodoo because if all CPUs in the mask are > offlined then the task is moved to a SMT enabled one where L1D flush is > useless. Though offlining their workhorse CPUs is probably not the daily > business for obvious raisins. >
Thanks, Thomas.
So, I will keep the semantics as-is, clean up the patch with preempt_{dis,en}able() and send out a v2.
Lukas
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