On Tue, 2 Oct 2012 17:59:11 +0100
Will Deacon <will.deacon@xxxxxxx> wrote:
> On x86 memory accesses to pages without the ACCESSED flag set result in the
> ACCESSED flag being set automatically. With the ARM architecture a page access
> fault is raised instead (and it will continue to be raised until the ACCESSED
> flag is set for the appropriate PTE/PMD).
>
> For normal memory pages, handle_pte_fault will call pte_mkyoung (effectively
> setting the ACCESSED flag). For transparent huge pages, pmd_mkyoung will only
> be called for a write fault.
>
> This patch ensures that faults on transparent hugepages which do not result
> in a CoW update the access flags for the faulting pmd.
Alas, the code you're altering has changed so much in linux-next that I
am reluctant to force this fix in there myself. Can you please
redo/retest/resend? You can do that on 3.7-rc1 if you like, then we
can feed this into -rc2.
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -3524,7 +3524,8 @@ retry:
>
> barrier();
> if (pmd_trans_huge(orig_pmd)) {
> - if (flags & FAULT_FLAG_WRITE &&
> + int dirty = flags & FAULT_FLAG_WRITE;
`flags' is `unsigned int', so making `dirty' match that is nicer.
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