allocation failures when cache eats all memory -- the updatedb issue

allocation failures when cache eats all memory -- the updatedb issue

[Craig Christophel]

[-- Attachment #1: Type: text/plain, Size: 205 bytes --]

The attached patch fixes all of these problems for me.  More than likley this 
is just covering the real issue, but the difference should allow someone with 
more VM talent than myself to fix.


Craig.




[-- Attachment #2: vmscan-alloc-fix.diff --]
[-- Type: text/x-diff, Size: 1929 bytes --]

--- linux/mm/vmscan.c	Sat Nov 17 22:18:17 2001
+++ linux.mt/mm/vmscan.c	Mon Dec 10 19:55:23 2001
@@ -531,13 +531,14 @@
  * We move them the other way when we see the
  * reference bit on the page.
  */
-static void refill_inactive(int nr_pages)
+static int refill_inactive(int nr_pages)
 {
 	struct list_head * entry;
+	int count = 0;
 
 	spin_lock(&pagemap_lru_lock);
 	entry = active_list.prev;
-	while (nr_pages-- && entry != &active_list) {
+	while (nr_pages && entry != &active_list) {
 		struct page * page;
 
 		page = list_entry(entry, struct page, lru);
@@ -545,14 +546,16 @@
 		if (PageTestandClearReferenced(page)) {
 			list_del(&page->lru);
 			list_add(&page->lru, &active_list);
-			continue;
+		} else {
+			del_page_from_active_list(page);
+			add_page_to_inactive_list(page);
+			SetPageReferenced(page);
+			nr_pages--;
+			count++;
 		}
-
-		del_page_from_active_list(page);
-		add_page_to_inactive_list(page);
-		SetPageReferenced(page);
 	}
 	spin_unlock(&pagemap_lru_lock);
+	return count;
 }
 
 static int FASTCALL(shrink_caches(zone_t * classzone, int priority, unsigned int gfp_mask, int nr_pages));
@@ -564,22 +567,24 @@
 	nr_pages -= kmem_cache_reap(gfp_mask);
 	if (nr_pages <= 0)
 		return 0;
+	shrink_dcache_memory(priority, gfp_mask);
+	shrink_icache_memory(priority, gfp_mask);
+#ifdef CONFIG_QUOTA
+	shrink_dqcache_memory(DEF_PRIORITY, gfp_mask);
+#endif
 
 	nr_pages = chunk_size;
 	/* try to keep the active list 2/3 of the size of the cache */
 	ratio = (unsigned long) nr_pages * nr_active_pages / ((nr_inactive_pages + 1) * 2);
+	if(!ratio)
+		ratio = nr_pages;
+
 	refill_inactive(ratio);
 
 	nr_pages = shrink_cache(nr_pages, classzone, gfp_mask, priority);
+
 	if (nr_pages <= 0)
 		return 0;
-
-	shrink_dcache_memory(priority, gfp_mask);
-	shrink_icache_memory(priority, gfp_mask);
-#ifdef CONFIG_QUOTA
-	shrink_dqcache_memory(DEF_PRIORITY, gfp_mask);
-#endif
-
 	return nr_pages;
 }