[Xen-devel] [PATCH v5 2/2] mm/page_alloc: remove software prefetching in __free_pages_core

[Arun KS <arunks@xxxxxxxxxxxxxx>]

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@xxxxxxxxx>
Signed-off-by: Arun KS <arunks@xxxxxxxxxxxxxx>
---
 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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