From: Christoph Lameter <clameter@sgi.com>
Date: Thu, 7 Dec 2006 04:33:02 +0000 (-0800)
Subject: [PATCH] drain_node_page(): Drain pages in batch units
X-Git-Tag: v2.6.20-rc1~15^2~14^2~326
X-Git-Url: http://ftp.safe.ca/?a=commitdiff_plain;h=bc4ba393c007248f76c05945abb7b7b892cdd1cc;p=safe%2Fjmp%2Flinux-2.6

[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>
---

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index a840e70..86f2984 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);
 			}
 		}