- ported from linux-2.4.25-atmdd.patch

[packages/kernel.git] / 350-autoswap

diff -upN reference/kernel/sysctl.c current/kernel/sysctl.c
--- reference/kernel/sysctl.c	2004-04-30 11:23:56.000000000 -0700
+++ current/kernel/sysctl.c	2004-05-02 08:41:25.000000000 -0700
@@ -721,11 +721,8 @@ static ctl_table vm_table[] = {
 		.procname	= "swappiness",
 		.data		= &vm_swappiness,
 		.maxlen		= sizeof(vm_swappiness),
-		.mode		= 0644,
-		.proc_handler	= &proc_dointvec_minmax,
-		.strategy	= &sysctl_intvec,
-		.extra1		= &zero,
-		.extra2		= &one_hundred,
+		.mode		= 0444 /* read-only*/,
+		.proc_handler	= &proc_dointvec,
 	},
 #ifdef CONFIG_HUGETLB_PAGE
 	 {
diff -upN reference/mm/vmscan.c current/mm/vmscan.c
--- reference/mm/vmscan.c	2004-04-30 11:23:57.000000000 -0700
+++ current/mm/vmscan.c	2004-05-02 08:41:25.000000000 -0700
@@ -42,7 +42,7 @@
 /*
  * From 0 .. 100.  Higher means more swappy.
  */
-int vm_swappiness = 60;
+int vm_swappiness = 0;
 static long total_memory;
 
 #define lru_to_page(_head) (list_entry((_head)->prev, struct page, lru))
@@ -586,6 +586,7 @@ refill_inactive_zone(struct zone *zone, 
 	LIST_HEAD(l_active);	/* Pages to go onto the active_list */
 	struct page *page;
 	struct pagevec pvec;
+	struct sysinfo i;
 	int reclaim_mapped = 0;
 	long mapped_ratio;
 	long distress;
@@ -627,14 +628,39 @@ refill_inactive_zone(struct zone *zone, 
 	 */
 	mapped_ratio = (ps->nr_mapped * 100) / total_memory;
 
+	si_swapinfo(&i);
+	if (likely(i.totalswap)) {
+		int app_centile, swap_centile;
+
+		/*
+		 * app_centile is the percentage of physical ram used
+		 * by application pages.
+		 */
+		si_meminfo(&i);
+		app_centile = 100 - ((i.freeram + get_page_cache_size() -
+			total_swapcache_pages) / (i.totalram / 100));
+
+		/*
+		 * swap_centile is the percentage of the last (sizeof physical
+		 * ram) of swap free.
+		 */
+		swap_centile = i.freeswap / 
+			(min(i.totalswap, i.totalram) / 100);
+
+		/*
+		 * Autoregulate vm_swappiness to be equal to the lowest of
+		 * app_centile and swap_centile. -ck
+		 */
+		vm_swappiness = min(app_centile, swap_centile);
+	} else 
+		vm_swappiness = 0;
+
 	/*
 	 * Now decide how much we really want to unmap some pages.  The mapped
 	 * ratio is downgraded - just because there's a lot of mapped memory
 	 * doesn't necessarily mean that page reclaim isn't succeeding.
 	 *
 	 * The distress ratio is important - we don't want to start going oom.
-	 *
-	 * A 100% value of vm_swappiness overrides this algorithm altogether.
 	 */
 	swap_tendency = mapped_ratio / 2 + distress + vm_swappiness;