The patch titled
Subject: mm/page_alloc.c: remove software prefetching in __free_pages_core()
has been added to the -mm tree. Its filename is
mm-page_alloc-remove-software-prefetching-in-__free_pages_core.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-page_alloc-remove-software-prefetching-in-__free_pages_core.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-page_alloc-remove-software-prefetching-in-__free_pages_core.patch
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------------------------------------------------------
From: Arun KS <arunks@xxxxxxxxxxxxxx>
Subject: mm/page_alloc.c: remove software prefetching in __free_pages_core()
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.
Link: http://lkml.kernel.org/r/1538727006-5727-2-git-send-email-arunks@xxxxxxxxxxxxxx
Signed-off-by: Arun KS <arunks@xxxxxxxxxxxxxx>
Suggested-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Aaron Lu <aaron.lu@xxxxxxxxx>
Cc: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>
Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Cc: Juergen Gross <jgross@xxxxxxxx>
Cc: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: K. Y. Srinivasan <kys@xxxxxxxxxxxxx>
Cc: Mathieu Malaterre <malat@xxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Oscar Salvador <osalvador@xxxxxxx>
Cc: Souptick Joarder <jrdr.linux@xxxxxxxxx>
Cc: Srivatsa Vaddagiri <vatsa@xxxxxxxxxxxxxx>
Cc: Stephen Hemminger <sthemmin@xxxxxxxxxxxxx>
Cc: Vinayak Menon <vinmenon@xxxxxxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/page_alloc.c | 6 +-----
1 file changed, 1 insertion(+), 5 deletions(-)
--- a/mm/page_alloc.c~mm-page_alloc-remove-software-prefetching-in-__free_pages_core
+++ a/mm/page_alloc.c
@@ -1264,14 +1264,10 @@ void __free_pages_core(struct page *page
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);
_
Patches currently in -mm which might be from arunks@xxxxxxxxxxxxxx are
memory_hotplug-free-pages-as-higher-order.patch
mm-page_alloc-remove-software-prefetching-in-__free_pages_core.patch
