MIGRATE_RECLAIMABLE allocations tend to be very bursty in nature like
when updatedb starts. It is likely this will occur in situations where
MAX_ORDER blocks of pages are not free. This means that updatedb can scatter
MIGRATE_RECLAIMABLE pages throughout the address space. This patch is more
agressive about stealing blocks of pages for MIGRATE_RECLAIMABLE.

Signed-off-by: Mel Gorman <[EMAIL PROTECTED]>
---

 page_alloc.c |   18 +++++++++++++++---
 1 files changed, 15 insertions(+), 3 deletions(-)

diff -rup -X /usr/src/patchset-0.6/bin//dontdiff 
linux-2.6.20-mm2-011_biasplacement/mm/page_alloc.c 
linux-2.6.20-mm2-012_grabbyreclaim/mm/page_alloc.c
--- linux-2.6.20-mm2-011_biasplacement/mm/page_alloc.c  2007-02-20 
18:52:18.000000000 +0000
+++ linux-2.6.20-mm2-012_grabbyreclaim/mm/page_alloc.c  2007-02-20 
18:54:35.000000000 +0000
@@ -806,11 +806,23 @@ retry:
 
                        /*
                         * If breaking a large block of pages, move all free
-                        * pages to the preferred allocation list
+                        * pages to the preferred allocation list. If falling
+                        * back for a reclaimable kernel allocation, be more
+                        * agressive about taking ownership of free pages
                         */
-                       if (unlikely(current_order >= MAX_ORDER / 2)) {
+                       if (unlikely(current_order >= MAX_ORDER / 2) ||
+                                       start_migratetype == 
MIGRATE_RECLAIMABLE) {
+                               unsigned long pages;
+                               pages = move_freepages_block(zone, page,
+                                                               
start_migratetype);
+
+                               /* Claim the whole block if over half of it is 
free */
+                               if ((pages << current_order) >= (1 << 
(MAX_ORDER-2)) &&
+                                               migratetype != 
MIGRATE_HIGHATOMIC)
+                                       set_pageblock_migratetype(page,
+                                                               
start_migratetype);
+
                                migratetype = start_migratetype;
-                               move_freepages_block(zone, page, migratetype);
                        }
 
                        /* Remove the page from the freelists */
-
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