Hi Matthew,
On Tue, Apr 28, 2020 at 9:44 PM Matthew Wilcox <willy@xxxxxxxxxxxxx> wrote:
> From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>
> Instead of a per-arch word within struct page, use a formerly reserved
> word. This word is shared with page->mapping, so it must be cleared
> before being freed as it is checked in free_pages().
>
> Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Thanks for your patch!
> --- a/include/linux/mm_types.h
> +++ b/include/linux/mm_types.h
> @@ -149,11 +149,8 @@ struct page {
> pgtable_t pmd_huge_pte;
> };
> };
> - unsigned long _pt_pad_2; /* mapping */
> - union {
> - struct mm_struct *pt_mm; /* x86 pgds only */
> - atomic_t pt_frag_refcount; /* powerpc */
> - };
> + struct mm_struct *pt_mm;
> + atomic_t pt_frag_refcount; /* powerpc */
So here is now an implicit hole on 64-bit platforms, right?
Do we have any where alignof(long) != 8?
> #if ALLOC_SPLIT_PTLOCKS
> spinlock_t *ptl;
> #else
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
