Re: [PATCH] mm: hugetlb: flush dcache before returning zeroed hugepage to userspace

From: Will Deacon
Date: Thu Aug 16 2012 - 14:33:06 EST


On Thu, Aug 16, 2012 at 07:20:15PM +0100, Michal Hocko wrote:
> On Thu 16-08-12 17:09:54, Will Deacon wrote:
> > +static inline void arch_clear_hugepage_flags(struct page *page)
> > +{
> > + flush_dcache_page(page);
> > +}
> > +
>
> Why do we need the hook for ia64? hugetlb_no_page calls clear_huge_page
> and that one calls flush_dcache_page (via clear_user_page), right?
> The same applies to copy_huge_page for COW.

You're right, these are redundant for ppc and ia64 (although ppc does have a
comment moaning about the flush). Looks like it's just sh and ARM that need to
do anything.

Cheers,

Will
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