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Subject[PATCH 31/35] Optimistically check the first page on the PCP free list is suitable
Date
The PCP lists are searched for a page of the suitable order. However,
the majority of pages are still expected to be order-0 pages and the
setup for the search is a bit expensive. This patch optimistically
checks if the first page is suitable for use in the hot-page allocation
path.

Signed-off-by: Mel Gorman <mel@csn.ul.ie>
---
mm/page_alloc.c | 6 ++++++
1 files changed, 6 insertions(+), 0 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index bb5bd5e..8568284 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1212,6 +1212,12 @@ again:
if (pcp_page_suit(page, order))
break;
} else {
+ /* Optimistic before we start a list search */
+ page = list_entry(list->next, struct page, lru);
+ if (pcp_page_suit(page, order))
+ goto found;
+
+ /* Do the search */
list_for_each_entry(page, list, lru)
if (pcp_page_suit(page, order))
break;
--
1.5.6.5


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