Messages in this thread | | | From | Atish Patra <> | Subject | Re: [v2 PATCH] RISC-V: Optimize tlb flush path. | Date | Tue, 20 Aug 2019 20:28:36 +0000 |
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On Tue, 2019-08-20 at 02:22 -0700, hch@infradead.org wrote: > On Tue, Aug 20, 2019 at 08:42:19AM +0000, Atish Patra wrote: > > cmask NULL is pretty common case and we would be unnecessarily > > executing bunch of instructions everytime while not saving much. > > Kernel > > still have to make an SBI call and OpenSBI is doing a local flush > > anyways. > > > > Looking at the code again, I think we can just use cpumask_weight > > and > > do local tlb flush only if local cpu is the only cpu present. > > > > Otherwise, it will just fall through and call > > sbi_remote_sfence_vma(). > > Maybe it is just time to split the different cases at a higher level. > The idea to multiple everything onto a single function always seemed > odd to me. > > FYI, here is what I do for the IPI based tlbflush for the native S- > mode > clint prototype, which seems much easier to understand: > > http://git.infradead.org/users/hch/riscv.git/commitdiff/ea4067ae61e20fcfcf46a6f6bd1cc25710ce3afe
This does seem a lot cleaner to me. We can reuse some of the code for this patch as well. Based on NATIVE_CLINT configuration, it will send an IPI or SBI call.
I can rebase my patch on top of yours and I can send it together or you can include in your series.
Let me know your preference.
-- Regards, Atish
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