Debug patch

Add some debug printk's to watch how the cpuset specific throttling code is
doing.

Signed-off-by: Christoph Lameter <clameter@sgi.com>

Index: linux-2.6.20-rc4-mm1/fs/fs-writeback.c
===================================================================
--- linux-2.6.20-rc4-mm1.orig/fs/fs-writeback.c	2007-01-12 13:01:25.000000000 -0800
+++ linux-2.6.20-rc4-mm1/fs/fs-writeback.c	2007-01-12 13:01:29.000000000 -0800
@@ -361,6 +361,8 @@
 				nodes_addr(*wbc->nodes), nr_node_ids)) {
 			/* No pages on nodes that we are flushing now */
 			list_move(&inode->i_list, &sb->s_dirty);
+			printk(KERN_INFO "sync_sb_inodes %p dirty_map=%lx allowed=%lx\n",
+				inode, inode->dirty_nodes.bits[0], wbc->nodes->bits[0]);
 			continue;
 		}
 #endif
Index: linux-2.6.20-rc4-mm1/mm/page-writeback.c
===================================================================
--- linux-2.6.20-rc4-mm1.orig/mm/page-writeback.c	2007-01-12 13:01:22.000000000 -0800
+++ linux-2.6.20-rc4-mm1/mm/page-writeback.c	2007-01-12 13:01:29.000000000 -0800
@@ -274,6 +274,9 @@
 			if (nr_reclaimable + dl.nr_writeback <= dl.thresh_dirty)
 						break;
 			pages_written += write_chunk - wbc.nr_to_write;
+			if (pages_written)
+				printk(KERN_INFO "Synchrononous writeback nodes=%lx wrote %ld pages triggered by inode %p\n",
+				cpuset_current_mems_allowed.bits[0], pages_written, mapping->host);
 			if (pages_written >= write_chunk)
 				break;		/* We've done our duty */
 		}
@@ -296,9 +299,12 @@
 	 * background_thresh, to keep the amount of dirty memory low.
 	 */
 	if ((laptop_mode && pages_written) ||
-	     (!laptop_mode && (nr_reclaimable > dl.thresh_background)))
+	     (!laptop_mode && (nr_reclaimable > dl.thresh_background))) {
+		printk(KERN_INFO "Background writeback nodes=%lx triggered by inode %p\n",
+				cpuset_current_mems_allowed.bits[0], mapping->host);
 		pdflush_operation(background_writeout, 0,
 			&cpuset_current_mems_allowed);
+	}
 }
 
 void set_page_dirty_balance(struct page *page)
@@ -418,10 +424,15 @@
  */
 int wakeup_pdflush(long nr_pages, nodemask_t *nodes)
 {
+	int rc;
+
 	if (nr_pages == 0)
 		nr_pages = global_page_state(NR_FILE_DIRTY) +
 				global_page_state(NR_UNSTABLE_NFS);
-	return pdflush_operation(background_writeout, nr_pages, nodes);
+	rc = pdflush_operation(background_writeout, nr_pages, nodes);
+	printk(KERN_INFO "wakeup_pdflush(%ld,%lx) == %d\n",nr_pages, nodes ? nodes->bits[0]: 0,
+		rc);
+	return rc;
 }
 
 static void wb_timer_fn(unsigned long unused);
@@ -832,6 +843,9 @@
 		if (mapping->host) {
 			/* !PageAnon && !swapper_space */
 			__mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
+			if (!node_isset(page_to_nid(page), mapping->host->dirty_nodes))
+printk(KERN_INFO "__set_page_dirty_nobuffers: Dirty map update inode=%p node=%d\n", mapping->host, page_to_nid(page));
+
 			cpuset_update_dirty_nodes(mapping->host, page);
 		}
 		return 1;
Index: linux-2.6.20-rc4-mm1/fs/buffer.c
===================================================================
--- linux-2.6.20-rc4-mm1.orig/fs/buffer.c	2007-01-12 12:59:59.000000000 -0800
+++ linux-2.6.20-rc4-mm1/fs/buffer.c	2007-01-12 13:01:29.000000000 -0800
@@ -741,6 +741,10 @@
 	}
 	write_unlock_irq(&mapping->tree_lock);
 	__mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
+	if (!node_isset(page_to_nid(page), mapping->host->dirty_nodes))
+		printk(KERN_INFO "__set_page_dirty_buffers: Dirty map update inode=%p node=%d\n",
+			mapping->host, page_to_nid(page));
+
 	cpuset_update_dirty_nodes(mapping->host, page);
 	return 1;
 }