Merge branch 'urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/writeback

* 'urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/writeback:
  squeeze max-pause area and drop pass-good area

2 files changed, 2 insertions, 24 deletions

diff --git a/include/linux/writeback.h b/include/linux/writeback.h
index f1bfa12ea246..2b8963ff0f35 100644
--- a/include/linux/writeback.h
+++ b/include/linux/writeback.h
@@ -12,15 +12,6 @@
  *
  *      (thresh - thresh/DIRTY_FULL_SCOPE, thresh)
  *
- * The 1/16 region above the global dirty limit will be put to maximum pauses:
- *
- *      (limit, limit + limit/DIRTY_MAXPAUSE_AREA)
- *
- * The 1/16 region above the max-pause region, dirty exceeded bdi's will be put
- * to loops:
- *
- *      (limit + limit/DIRTY_MAXPAUSE_AREA, limit + limit/DIRTY_PASSGOOD_AREA)
- *
  * Further beyond, all dirtier tasks will enter a loop waiting (possibly long
  * time) for the dirty pages to drop, unless written enough pages.
  *
@@ -31,8 +22,6 @@
  */
 #define DIRTY_SCOPE             8
 #define DIRTY_FULL_SCOPE        (DIRTY_SCOPE / 2)
-#define DIRTY_MAXPAUSE_AREA             16
-#define DIRTY_PASSGOOD_AREA             8
 
 /*
  * 4MB minimal write chunk size
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index d1960744f881..0e309cd1b5b9 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -754,21 +754,10 @@ static void balance_dirty_pages(struct address_space *mapping,
                  * 200ms is typically more than enough to curb heavy dirtiers;
                  * (b) the pause time limit makes the dirtiers more responsive.
                  */
-                if (nr_dirty < dirty_thresh +
-                               dirty_thresh / DIRTY_MAXPAUSE_AREA &&
+                if (nr_dirty < dirty_thresh &&
+                    bdi_dirty < (task_bdi_thresh + bdi_thresh) / 2 &&
                     time_after(jiffies, start_time + MAX_PAUSE))
                         break;
-                /*
-                 * pass-good area. When some bdi gets blocked (eg. NFS server
-                 * not responding), or write bandwidth dropped dramatically due
-                 * to concurrent reads, or dirty threshold suddenly dropped and
-                 * the dirty pages cannot be brought down anytime soon (eg. on
-                 * slow USB stick), at least let go of the good bdi's.
-                 */
-                if (nr_dirty < dirty_thresh +
-                               dirty_thresh / DIRTY_PASSGOOD_AREA &&
-                    bdi_dirty < bdi_thresh)
-                        break;
 
                 /*
                  * Increase the delay for each loop, up to our previous