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authorVlastimil Babka <vbabka@suse.cz>2017-02-22 15:41:51 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2017-02-22 16:41:27 -0800
commit13ad59df67f19788f6c22985b1a33e466eceb643 (patch)
tree98644ed581610f3af1d52f01963627e94317f2cd
parent76741e776a37973a3e398d504069b3e55c5cc866 (diff)
mm, page_alloc: avoid page_to_pfn() when merging buddies
On architectures that allow memory holes, page_is_buddy() has to perform page_to_pfn() to check for the memory hole. After the previous patch, we have the pfn already available in __free_one_page(), which is the only caller of page_is_buddy(), so move the check there and avoid page_to_pfn(). Link: http://lkml.kernel.org/r/20161216120009.20064-2-vbabka@suse.cz Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Mel Gorman <mgorman@techsingularity.net> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/page_alloc.c10
-rw-r--r--mm/page_isolation.c2
2 files changed, 6 insertions, 6 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 49d40261f8c4..af65c4eedc79 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -714,7 +714,7 @@ static inline void rmv_page_order(struct page *page)
/*
* This function checks whether a page is free && is the buddy
* we can do coalesce a page and its buddy if
- * (a) the buddy is not in a hole &&
+ * (a) the buddy is not in a hole (check before calling!) &&
* (b) the buddy is in the buddy system &&
* (c) a page and its buddy have the same order &&
* (d) a page and its buddy are in the same zone.
@@ -729,9 +729,6 @@ static inline void rmv_page_order(struct page *page)
static inline int page_is_buddy(struct page *page, struct page *buddy,
unsigned int order)
{
- if (!pfn_valid_within(page_to_pfn(buddy)))
- return 0;
-
if (page_is_guard(buddy) && page_order(buddy) == order) {
if (page_zone_id(page) != page_zone_id(buddy))
return 0;
@@ -808,6 +805,9 @@ continue_merging:
while (order < max_order - 1) {
buddy_pfn = __find_buddy_pfn(pfn, order);
buddy = page + (buddy_pfn - pfn);
+
+ if (!pfn_valid_within(buddy_pfn))
+ goto done_merging;
if (!page_is_buddy(page, buddy, order))
goto done_merging;
/*
@@ -862,7 +862,7 @@ done_merging:
* so it's less likely to be used soon and more likely to be merged
* as a higher order page
*/
- if ((order < MAX_ORDER-2) && pfn_valid_within(page_to_pfn(buddy))) {
+ if ((order < MAX_ORDER-2) && pfn_valid_within(buddy_pfn)) {
struct page *higher_page, *higher_buddy;
combined_pfn = buddy_pfn & pfn;
higher_page = page + (combined_pfn - pfn);
diff --git a/mm/page_isolation.c b/mm/page_isolation.c
index dadb7e74d7d6..f4e17a57926a 100644
--- a/mm/page_isolation.c
+++ b/mm/page_isolation.c
@@ -106,7 +106,7 @@ static void unset_migratetype_isolate(struct page *page, unsigned migratetype)
buddy_pfn = __find_buddy_pfn(pfn, order);
buddy = page + (buddy_pfn - pfn);
- if (pfn_valid_within(page_to_pfn(buddy)) &&
+ if (pfn_valid_within(buddy_pfn) &&
!is_migrate_isolate_page(buddy)) {
__isolate_free_page(page, order);
isolated_page = true;

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