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Subject[PATCH v5 2/2] mm/page_alloc: remove software prefetching in __free_pages_core
Date
They not only increase the code footprint, they actually make things
slower rather than faster. Remove them as contemporary hardware doesn't
need any hint.

Suggested-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Arun KS <arunks@codeaurora.org>
---
mm/page_alloc.c | 6 +-----
1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 7ab5274..90db431 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1258,14 +1258,10 @@ void __free_pages_core(struct page *page, unsigned int order)
struct page *p = page;
unsigned int loop;

- prefetchw(p);
- for (loop = 0; loop < (nr_pages - 1); loop++, p++) {
- prefetchw(p + 1);
+ for (loop = 0; loop < nr_pages ; loop++, p++) {
__ClearPageReserved(p);
set_page_count(p, 0);
}
- __ClearPageReserved(p);
- set_page_count(p, 0);

page_zone(page)->managed_pages += nr_pages;
set_page_refcounted(page);
--
1.9.1
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