The patch titled
page allocator: do not call get_pageblock_migratetype() more than necessary
has been added to the -mm tree. Its filename is
page-allocator-do-not-call-get_pageblock_migratetype-more-than-necessary.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find
out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: page allocator: do not call get_pageblock_migratetype() more than necessary
From: Mel Gorman <mel@xxxxxxxxx>
get_pageblock_migratetype() is potentially called twice for every page
free. Once, when being freed to the pcp lists and once when being freed
back to buddy. When freeing from the pcp lists, it is known what the
pageblock type was at the time of free so use it rather than rechecking.
In low memory situations under memory pressure, this might skew
anti-fragmentation slightly but the interference is minimal and decisions
that are fragmenting memory are being made anyway.
Signed-off-by: Mel Gorman <mel@xxxxxxxxx>
Reviewed-by: Christoph Lameter <cl@xxxxxxxxxxxxxxxxxxxx>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
Cc: Pekka Enberg <penberg@xxxxxxxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Nick Piggin <nickpiggin@xxxxxxxxxxxx>
Cc: Dave Hansen <dave@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/page_alloc.c | 16 ++++++++++------
1 file changed, 10 insertions(+), 6 deletions(-)
diff -puN mm/page_alloc.c~page-allocator-do-not-call-get_pageblock_migratetype-more-than-necessary mm/page_alloc.c
--- a/mm/page_alloc.c~page-allocator-do-not-call-get_pageblock_migratetype-more-than-necessary
+++ a/mm/page_alloc.c
@@ -456,16 +456,18 @@ static inline int page_is_buddy(struct p
*/
static inline void __free_one_page(struct page *page,
- struct zone *zone, unsigned int order)
+ struct zone *zone, unsigned int order,
+ int migratetype)
{
unsigned long page_idx;
int order_size = 1 << order;
- int migratetype = get_pageblock_migratetype(page);
if (unlikely(PageCompound(page)))
if (unlikely(destroy_compound_page(page, order)))
return;
+ VM_BUG_ON(migratetype == -1);
+
page_idx = page_to_pfn(page) & ((1 << MAX_ORDER) - 1);
VM_BUG_ON(page_idx & (order_size - 1));
@@ -534,17 +536,18 @@ static void free_pages_bulk(struct zone
page = list_entry(list->prev, struct page, lru);
/* have to delete it as __free_one_page list manipulates */
list_del(&page->lru);
- __free_one_page(page, zone, order);
+ __free_one_page(page, zone, order, page_private(page));
}
spin_unlock(&zone->lock);
}
-static void free_one_page(struct zone *zone, struct page *page, int order)
+static void free_one_page(struct zone *zone, struct page *page, int order,
+ int migratetype)
{
spin_lock(&zone->lock);
zone_clear_flag(zone, ZONE_ALL_UNRECLAIMABLE);
zone->pages_scanned = 0;
- __free_one_page(page, zone, order);
+ __free_one_page(page, zone, order, migratetype);
spin_unlock(&zone->lock);
}
@@ -569,7 +572,8 @@ static void __free_pages_ok(struct page
local_irq_save(flags);
__count_vm_events(PGFREE, 1 << order);
- free_one_page(page_zone(page), page, order);
+ free_one_page(page_zone(page), page, order,
+ get_pageblock_migratetype(page));
local_irq_restore(flags);
}
_
Patches currently in -mm which might be from mel@xxxxxxxxx are
vmscan-low-order-lumpy-reclaim-also-should-use-pageout_io_sync.patch
page-allocator-replace-__alloc_pages_internal-with-__alloc_pages_nodemask.patch
page-allocator-do-not-sanity-check-order-in-the-fast-path.patch
page-allocator-do-not-sanity-check-order-in-the-fast-path-fix.patch
page-allocator-do-not-check-numa-node-id-when-the-caller-knows-the-node-is-valid.patch
page-allocator-check-only-once-if-the-zonelist-is-suitable-for-the-allocation.patch
page-allocator-break-up-the-allocator-entry-point-into-fast-and-slow-paths.patch
page-allocator-move-check-for-disabled-anti-fragmentation-out-of-fastpath.patch
page-allocator-calculate-the-preferred-zone-for-allocation-only-once.patch
page-allocator-calculate-the-preferred-zone-for-allocation-only-once-fix.patch
page-allocator-calculate-the-migratetype-for-allocation-only-once.patch
page-allocator-calculate-the-alloc_flags-for-allocation-only-once.patch
page-allocator-remove-a-branch-by-assuming-__gfp_high-==-alloc_high.patch
page-allocator-inline-__rmqueue_smallest.patch
page-allocator-inline-buffered_rmqueue.patch
page-allocator-inline-__rmqueue_fallback.patch
page-allocator-do-not-call-get_pageblock_migratetype-more-than-necessary.patch
page-allocator-do-not-disable-interrupts-in-free_page_mlock.patch
page-allocator-do-not-setup-zonelist-cache-when-there-is-only-one-node.patch
page-allocator-do-not-check-for-compound-pages-during-the-page-allocator-sanity-checks.patch
page-allocator-use-allocation-flags-as-an-index-to-the-zone-watermark.patch
page-allocator-update-nr_free_pages-only-as-necessary.patch
page-allocator-get-the-pageblock-migratetype-without-disabling-interrupts.patch
page-allocator-use-a-pre-calculated-value-instead-of-num_online_nodes-in-fast-paths.patch
page-allocator-slab-use-nr_online_nodes-to-check-for-a-numa-platform.patch
add-debugging-aid-for-memory-initialisation-problems.patch
--
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