Re: [PATCH 2/9] mm/page_alloc: Add a bulk page allocator

Mel Gorman
2021-03-25T12:38:12Z

On Thu, Mar 25, 2021 at 12:05:25PM +0000, Matthew Wilcox wrote:
> On Thu, Mar 25, 2021 at 11:42:21AM +0000, Mel Gorman wrote:
> > +int __alloc_pages_bulk(gfp_t gfp, int preferred_nid,
> > + nodemask_t *nodemask, int nr_pages,
> > + struct list_head *list);
> > +
> > +/* Bulk allocate order-0 pages */
> > +static inline unsigned long
> > +alloc_pages_bulk(gfp_t gfp, unsigned long nr_pages, struct list_head *list)
> > +{
> > + return __alloc_pages_bulk(gfp, numa_mem_id(), NULL, nr_pages, list);
>
> Discrepancy in the two return types here. Suspect they should both
> be 'unsigned int' so there's no question about "can it return an errno".
>

I'll make it unsigned long as the nr_pages parameter is unsigned long.
It's a silly range to have for pages but it matches alloc_contig_range
even though free_contig_range takes unsigned int *sigh*

> >
> > +/*
>
> If you could make that "/**" instead ...
>

I decided not to until we're reasonably sure the semantics are not going
to change.

---8<---
mm/page_alloc: Add a bulk page allocator -fix

Matthew Wilcox pointed out that the return type for alloc_pages_bulk()
and __alloc_pages_bulk() is inconsistent. Fix it.

Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
---
include/linux/gfp.h | 2 +-
mm/page_alloc.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/linux/gfp.h b/include/linux/gfp.h
index 4a304fd39916..a2be8f4174a9 100644
--- a/include/linux/gfp.h
+++ b/include/linux/gfp.h
@@ -518,7 +518,7 @@ static inline int arch_make_page_accessible(struct page *page)
struct page *__alloc_pages(gfp_t gfp, unsigned int order, int preferred_nid,
nodemask_t *nodemask);

-int __alloc_pages_bulk(gfp_t gfp, int preferred_nid,
+unsigned long __alloc_pages_bulk(gfp_t gfp, int preferred_nid,
nodemask_t *nodemask, int nr_pages,
struct list_head *list);

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index eb547470a7e4..92d55f80c289 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -4978,7 +4978,7 @@ static inline bool prepare_alloc_pages(gfp_t gfp_mask, unsigned int order,
*
* Returns the number of pages on the list.
*/
-int __alloc_pages_bulk(gfp_t gfp, int preferred_nid,
+unsigned long __alloc_pages_bulk(gfp_t gfp, int preferred_nid,
nodemask_t *nodemask, int nr_pages,
struct list_head *page_list)
{