From: Christoph Lameter <clameter@engr.sgi.com>
Date: Wed, 1 Feb 2006 11:05:32 +0000 (-0800)
Subject: [PATCH] zone_reclaim: do not unmap file backed pages
X-Git-Tag: v2.6.16-rc2~108
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=aa3f18b3391ac305baa01faead3fdf9147daf54b;p=linux-2.6

[PATCH] zone_reclaim: do not unmap file backed pages

zone_reclaim should leave that to the real swapper.  We are only interested
in evicting unmapped pages.

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/vmscan.c b/mm/vmscan.c
index 61ca0097c8..8277f93148 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -477,6 +477,12 @@ static int shrink_list(struct list_head *page_list, struct scan_control *sc)
 		 * processes. Try to unmap it here.
 		 */
 		if (page_mapped(page) && mapping) {
+			/*
+			 * No unmapping if we do not swap
+			 */
+			if (!sc->may_swap)
+				goto keep_locked;
+
 			switch (try_to_unmap(page)) {
 			case SWAP_FAIL:
 				goto activate_locked;