Re: [RFC][PATCH 03/11] x86/mm: Page size aware flush_tlb_mm_range()

[Dave Hansen]

On 09/13/2018 11:46 AM, Peter Zijlstra wrote:
> On Thu, Sep 13, 2018 at 08:42:30PM +0200, Peter Zijlstra wrote:
>>>> +#define flush_tlb_range(vma, start, end)			\
>>>> +		flush_tlb_mm_range((vma)->vm_mm, start, end,	\
>>>> +				(vma)->vm_flags & VM_HUGETLB ? PMD_SHIFT : PAGE_SHIFT)
>>> This is safe.  But, Couldn't this PMD_SHIFT also be PUD_SHIFT for a 1G
>>> hugetlb page?
>> It could be, but can we tell at that point?
> I had me a look in higetlb.h, would something like so work?
> 
> #define flush_tlb_range(vma, start, end)			\
> 	flush_tlb_mm_range((vma)->vm_mm, start, end,		\
> 			   huge_page_shift(hstate_vma(vma)))
> 

I think you still need the VM_HUGETLB check somewhere because
hstate_vma() won't work on non-VM_HUGETLB VMAs.  But, yeah, something
close to that should be OK.