Re: [PATCH v5 5/7] x86/tlb: add tlb_flushall_shift for specific CPU

From: H. Peter Anvin
Date: Wed May 16 2012 - 13:57:12 EST


On 05/15/2012 11:49 PM, Alex Shi wrote:
> + if (!cpu_has_invlpg || vma->vm_flags & VM_HUGETLB
> + || tlb_flushall_shift == (u16)TLB_FLUSH_ALL) {

I asked for you to fold the cpu_has_invlpg test into tlb_flushall_shift.
Also, (u16)TLB_FLUSH_ALL really is hit up with the ugly stick... why on
earth is this u16? It's a bit shift, so it can't be bigger than 6 bits
anyway... and if you want to be able to use -1 as a sentinel you might
as well make it a signed value and use < 0 or == -1 as the test.

Am I missing something really fundamental here?

-hpa

--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.

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