[PATCH] Fix vmi time header bug

[powerpc.git] / mm / page-writeback.c

diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 1d2fc89..f469e3c 100644 (file)
--- 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
 
 
@@ -298,11 +296,21 @@ void balance_dirty_pages_ratelimited_nr(struct address_space *mapping,
 }
 EXPORT_SYMBOL(balance_dirty_pages_ratelimited_nr);
 
-void throttle_vm_writeout(void)
+void throttle_vm_writeout(gfp_t gfp_mask)
 {
        long background_thresh;
        long dirty_thresh;
 
+       if ((gfp_mask & (__GFP_FS|__GFP_IO)) != (__GFP_FS|__GFP_IO)) {
+               /*
+                * The caller might hold locks which can prevent IO completion
+                * or progress in the filesystem.  So we cannot just sit here
+                * waiting for IO to complete.
+                */
+               congestion_wait(WRITE, HZ/10);
+               return;
+       }
+
         for ( ; ; ) {
                get_dirty_limits(&background_thresh, &dirty_thresh, NULL);
 
@@ -319,7 +327,6 @@ void throttle_vm_writeout(void)
         }
 }
 
-
 /*
  * writeback at least _min_pages, and keep writing until the amount of dirty
  * memory is less than the background threshold, or until we're all clean.
@@ -517,7 +524,7 @@ 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 +533,32 @@ 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 +705,6 @@ 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 +742,16 @@ 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.