X-Git-Url: http://pilppa.org/gitweb/gitweb.cgi?a=blobdiff_plain;f=mm%2Fpage-writeback.c;h=f7e088f5a309eff3a03c8da5ad4ca4b37ecd5518;hb=690b8d9d54941c90af1d43b0cc24903d20386f5b;hp=1d2fc89ca56d522c0811db6fe5022ef9c2fa17c7;hpb=7658cc289288b8ae7dd2c2224549a048431222b3;p=linux-2.6-omap-h63xx.git

diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 1d2fc89ca56..f7e088f5a30 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -133,11 +133,9 @@ get_dirty_limits(long *pbackground, long *pdirty,
 
 #ifdef CONFIG_HIGHMEM
 	/*
-	 * If this mapping can only allocate from low memory,
-	 * we exclude high memory from our count.
+	 * We always exclude high memory from our count.
 	 */
-	if (mapping && !(mapping_gfp_mask(mapping) & __GFP_HIGHMEM))
-		available_memory -= totalhigh_pages;
+	available_memory -= totalhigh_pages;
 #endif
 
 
@@ -517,7 +515,7 @@ static int __cpuinit
 ratelimit_handler(struct notifier_block *self, unsigned long u, void *v)
 {
 	writeback_set_ratelimit();
-	return 0;
+	return NOTIFY_DONE;
 }
 
 static struct notifier_block __cpuinitdata ratelimit_nb = {
@@ -526,37 +524,32 @@ static struct notifier_block __cpuinitdata ratelimit_nb = {
 };
 
 /*
- * If the machine has a large highmem:lowmem ratio then scale back the default
- * dirty memory thresholds: allowing too much dirty highmem pins an excessive
- * number of buffer_heads.
+ * Called early on to tune the page writeback dirty limits.
+ *
+ * We used to scale dirty pages according to how total memory
+ * related to pages that could be allocated for buffers (by
+ * comparing nr_free_buffer_pages() to vm_total_pages.
+ *
+ * However, that was when we used "dirty_ratio" to scale with
+ * all memory, and we don't do that any more. "dirty_ratio"
+ * is now applied to total non-HIGHPAGE memory (by subtracting
+ * totalhigh_pages from vm_total_pages), and as such we can't
+ * get into the old insane situation any more where we had
+ * large amounts of dirty pages compared to a small amount of
+ * non-HIGHMEM memory.
+ *
+ * But we might still want to scale the dirty_ratio by how
+ * much memory the box has..
  */
 void __init page_writeback_init(void)
 {
-	long buffer_pages = nr_free_buffer_pages();
-	long correction;
-
-	correction = (100 * 4 * buffer_pages) / vm_total_pages;
-
-	if (correction < 100) {
-		dirty_background_ratio *= correction;
-		dirty_background_ratio /= 100;
-		vm_dirty_ratio *= correction;
-		vm_dirty_ratio /= 100;
-
-		if (dirty_background_ratio <= 0)
-			dirty_background_ratio = 1;
-		if (vm_dirty_ratio <= 0)
-			vm_dirty_ratio = 1;
-	}
 	mod_timer(&wb_timer, jiffies + dirty_writeback_interval);
 	writeback_set_ratelimit();
 	register_cpu_notifier(&ratelimit_nb);
 }
 
 /**
- * generic_writepages - walk the list of dirty pages of the given
- *                      address space and writepage() all of them.
- *
+ * generic_writepages - walk the list of dirty pages of the given address space and writepage() all of them.
  * @mapping: address space structure to write
  * @wbc: subtract the number of written pages from *@wbc->nr_to_write
  *
@@ -703,7 +696,6 @@ int do_writepages(struct address_space *mapping, struct writeback_control *wbc)
 
 /**
  * write_one_page - write out a single page and optionally wait on I/O
- *
  * @page: the page to write
  * @wait: if true, wait on writeout
  *
@@ -741,6 +733,16 @@ int write_one_page(struct page *page, int wait)
 }
 EXPORT_SYMBOL(write_one_page);
 
+/*
+ * For address_spaces which do not use buffers nor write back.
+ */
+int __set_page_dirty_no_writeback(struct page *page)
+{
+	if (!PageDirty(page))
+		SetPageDirty(page);
+	return 0;
+}
+
 /*
  * For address_spaces which do not use buffers.  Just tag the page as dirty in
  * its radix tree.