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
