Re: [PATCH 05 of 66] compound_lock

Andrea Arcangeli
2010-11-25T16:23:50Z

On Thu, Nov 18, 2010 at 09:28:27AM -0800, Linus Torvalds wrote:
> On Thu, Nov 18, 2010 at 3:49 AM, Mel Gorman <mel@csn.ul.ie> wrote:
> >> +
> >> +static inline void compound_lock_irqsave(struct page *page,
> >> +                                      unsigned long *flagsp)
> >> +{
> >> +#ifdef CONFIG_TRANSPARENT_HUGEPAGE
> >> +     unsigned long flags;
> >> +     local_irq_save(flags);
> >> +     compound_lock(page);
> >> +     *flagsp = flags;
> >> +#endif
> >> +}
> >> +
> >
> > The pattern for spinlock irqsave passes in unsigned long, not unsigned
> > long *. It'd be nice if they matched.
>
> Indeed. Just make the thing return the flags the way the normal
> spin_lock_irqsave() function does.

Done.

diff --git a/include/linux/mm.h b/include/linux/mm.h
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -320,15 +320,14 @@ static inline void compound_unlock(struc
#endif
}

-static inline void compound_lock_irqsave(struct page *page,
- unsigned long *flagsp)
+static inline unsigned long compound_lock_irqsave(struct page *page)
{
+ unsigned long uninitialized_var(flags);
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
- unsigned long flags;
local_irq_save(flags);
compound_lock(page);
- *flagsp = flags;
#endif
+ return flags;
}

static inline void compound_unlock_irqrestore(struct page *page,

diff --git a/mm/swap.c b/mm/swap.c
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -94,7 +94,7 @@ static void put_compound_page(struct pag
*/
smp_mb();
/* page_head wasn't a dangling pointer */
- compound_lock_irqsave(page_head, &flags);
+ flags = compound_lock_irqsave(page_head);
if (unlikely(!PageTail(page))) {
/* __split_huge_page_refcount run before us */
compound_unlock_irqrestore(page_head, flags);

Thanks,
Andrea