Re: [PATCH] mm/hugetlb: remove unnecessary memory fetch in PageHeadHuge()

[Kirill A. Shutemov]

On Thu, Mar 12, 2020 at 03:41:19AM +0300, Kirill A. Shutemov wrote:
> On Wed, Mar 11, 2020 at 06:24:40PM +0100, Vlastimil Babka wrote:
> > Commit f1e61557f023 ("mm: pack compound_dtor and compound_order into one word
> > in struct page") changed compound_dtor from a pointer to an array index in
> > order to pack it. To check if page has the hugeltbfs compound_dtor, we can
> > just compare the index directly without fetching the function pointer.
> > Said commit did that with PageHuge() and we can do the same with PageHeadHuge()
> > to make the code a bit smaller and faster.
> > 
> > Signed-off-by: Vlastimil Babka <vbabka@xxxxxxx>
> > Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
> > Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
> 
> Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
> 
> We use literaly the same check in the function next to this one --
> PageHuge().

Ugh.. I have to read the commit message, not only the code :P

-- 
 Kirill A. Shutemov