[PATCH] drain_node_page(): Drain pages in batch units

drain_node_pages() currently drains the complete pageset of all pages.  If
there are a large number of pages in the queues then we may hold off
interrupts for too long.

Duplicate the method used in free_hot_cold_page.  Only drain pcp->batch
pages at one time.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 8 insertions, 2 deletions

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index a840e702722c..86f2984f8b79 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -685,9 +685,15 @@ void drain_node_pages(int nodeid)
 
                         pcp = &pset->pcp[i];
                         if (pcp->count) {
+                                int to_drain;
+
                                 local_irq_save(flags);
-                                free_pages_bulk(zone, pcp->count, &pcp->list, 0);
-                                pcp->count = 0;
+                                if (pcp->count >= pcp->batch)
+                                        to_drain = pcp->batch;
+                                else
+                                        to_drain = pcp->count;
+                                free_pages_bulk(zone, to_drain, &pcp->list, 0);
+                                pcp->count -= to_drain;
                                 local_irq_restore(flags);
                         }
                 }