Merge git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile

[firefly-linux-kernel-4.4.55.git] / mm / page-writeback.c

diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 45e187b2d97183a90df9a5ee8558404f9f1bd826..5daf5568b9e149ea9dce0383b0452bd30ad67f84 100644 (file)
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -857,8 +857,11 @@ static void bdi_update_write_bandwidth(struct backing_dev_info *bdi,
         *                   bw * elapsed + write_bandwidth * (period - elapsed)
         * write_bandwidth = ---------------------------------------------------
         *                                          period
+        *
+        * @written may have decreased due to account_page_redirty().
+        * Avoid underflowing @bw calculation.
         */
-       bw = written - bdi->written_stamp;
+       bw = written - min(written, bdi->written_stamp);
        bw *= HZ;
        if (unlikely(elapsed > period)) {
                do_div(bw, elapsed);
@@ -922,7 +925,7 @@ static void global_update_bandwidth(unsigned long thresh,
                                    unsigned long now)
 {
        static DEFINE_SPINLOCK(dirty_lock);
-       static unsigned long update_time;
+       static unsigned long update_time = INITIAL_JIFFIES;
 
        /*
         * check locklessly first to optimize away locking for the most time
@@ -2107,6 +2110,25 @@ void account_page_dirtied(struct page *page, struct address_space *mapping)
 }
 EXPORT_SYMBOL(account_page_dirtied);
 
+/*
+ * Helper function for deaccounting dirty page without writeback.
+ *
+ * Doing this should *normally* only ever be done when a page
+ * is truncated, and is not actually mapped anywhere at all. However,
+ * fs/buffer.c does this when it notices that somebody has cleaned
+ * out all the buffers on a page without actually doing it through
+ * the VM. Can you say "ext3 is horribly ugly"? Thought you could.
+ */
+void account_page_cleaned(struct page *page, struct address_space *mapping)
+{
+       if (mapping_cap_account_dirty(mapping)) {
+               dec_zone_page_state(page, NR_FILE_DIRTY);
+               dec_bdi_stat(inode_to_bdi(mapping->host), BDI_RECLAIMABLE);
+               task_io_account_cancelled_write(PAGE_CACHE_SIZE);
+       }
+}
+EXPORT_SYMBOL(account_page_cleaned);
+
 /*
  * For address_spaces which do not use buffers.  Just tag the page as dirty in
  * its radix tree.
@@ -2206,7 +2228,8 @@ int set_page_dirty(struct page *page)
                 * it will confuse readahead and make it restart the size rampup
                 * process. But it's a trivial problem.
                 */
-               ClearPageReclaim(page);
+               if (PageReclaim(page))
+                       ClearPageReclaim(page);
 #ifdef CONFIG_BLOCK
                if (!spd)
                        spd = __set_page_dirty_buffers;