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Date:   Tue, 3 Apr 2018 13:45:18 -0700 (PDT)
From:   David Rientjes <rientjes@google.com>
To:     Jerome Glisse <jglisse@redhat.com>
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Subject: Re: [PATCH v9 15/24] mm: Introduce __vm_normal_page()
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On Tue, 3 Apr 2018, Jerome Glisse wrote:

> > When dealing with the speculative fault path we should use the VMA's field
> > cached value stored in the vm_fault structure.
> > 
> > Currently vm_normal_page() is using the pointer to the VMA to fetch the
> > vm_flags value. This patch provides a new __vm_normal_page() which is
> > receiving the vm_flags flags value as parameter.
> > 
> > Note: The speculative path is turned on for architecture providing support
> > for special PTE flag. So only the first block of vm_normal_page is used
> > during the speculative path.
> 
> Might be a good idea to explicitly have SPECULATIVE Kconfig option depends
> on ARCH_PTE_SPECIAL and a comment for !HAVE_PTE_SPECIAL in the function
> explaining that speculative page fault should never reach that point.

Yeah, I think that's appropriate but in a follow-up patch since this is 
only propagating vma_flags.  It will require that __HAVE_ARCH_PTE_SPECIAL 
become an actual Kconfig entry, however.