Re: [PATCH 14/28] mm, page_alloc: Simplify last cpupid reset

From: Vlastimil Babka
Date: Tue Apr 26 2016 - 09:30:56 EST


On 04/15/2016 11:07 AM, Mel Gorman wrote:
The current reset unnecessarily clears flags and makes pointless calculations.

Ugh, indeed.

Signed-off-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>

Acked-by: Vlastimil Babka <vbabka@xxxxxxx>

---
include/linux/mm.h | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index ffcff53e3b2b..60656db00abd 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -837,10 +837,7 @@ extern int page_cpupid_xchg_last(struct page *page, int cpupid);

static inline void page_cpupid_reset_last(struct page *page)
{
- int cpupid = (1 << LAST_CPUPID_SHIFT) - 1;
-
- page->flags &= ~(LAST_CPUPID_MASK << LAST_CPUPID_PGSHIFT);
- page->flags |= (cpupid & LAST_CPUPID_MASK) << LAST_CPUPID_PGSHIFT;
+ page->flags |= LAST_CPUPID_MASK << LAST_CPUPID_PGSHIFT;
}
#endif /* LAST_CPUPID_NOT_IN_PAGE_FLAGS */
#else /* !CONFIG_NUMA_BALANCING */