[PATCH] unlazy page movement

[Rik van Riel <riel@conectiva.com.br>]

Hi Alan,

since the VM balancing just about depends on the fact that
the pages it encounters on the inactive_clean list really
are freeable, here is a small patch to unlazy the queue
movement whenever we touch inactive page cache pages.

Please consider applying for the next -ac kernel.

thanks,

Rik
--
IA64: a worthy successor to i860.


--- filemap.c.orig	Mon Aug 13 14:19:58 2001
+++ filemap.c	Tue Aug 14 00:09:14 2001
@@ -353,8 +353,16 @@
 		if (page->index == offset)
 			break;
 	}
-	/* Mark the page referenced, kswapd will find it later. */
-	SetPageReferenced(page);
+	/*
+	 * Mark the page referenced so kswapd knows to up page->age
+	 * the next VM scan. Make sure to move inactive pages to the
+	 * active list so we don't get a nasty surprise when the pages
+	 * we thought were freeable aren't...
+	 */
+	if (PageActive(page))
+		SetPageReferenced(page);
+	else
+		activate_page(page);

 not_found:
 	return page;

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