Merge branch 'mpi-master' into wip-k-fmlpwip-k-fmlp

Conflicts:
	litmus/sched_cedf.c

1 files changed, 47 insertions, 20 deletions

diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index e3bccac1f025..31f698862420 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -404,25 +404,22 @@ unsigned long determine_dirtyable_memory(void)
  * - vm.dirty_background_ratio  or  vm.dirty_background_bytes
  * - vm.dirty_ratio             or  vm.dirty_bytes
  * The dirty limits will be lifted by 1/4 for PF_LESS_THROTTLE (ie. nfsd) and
- * runtime tasks.
+ * real-time tasks.
  */
 void global_dirty_limits(unsigned long *pbackground, unsigned long *pdirty)
 {
         unsigned long background;
         unsigned long dirty;
-        unsigned long available_memory = determine_dirtyable_memory();
+        unsigned long uninitialized_var(available_memory);
         struct task_struct *tsk;
 
+        if (!vm_dirty_bytes || !dirty_background_bytes)
+                available_memory = determine_dirtyable_memory();
+
         if (vm_dirty_bytes)
                 dirty = DIV_ROUND_UP(vm_dirty_bytes, PAGE_SIZE);
-        else {
-                int dirty_ratio;
-
-                dirty_ratio = vm_dirty_ratio;
-                if (dirty_ratio < 5)
-                        dirty_ratio = 5;
-                dirty = (dirty_ratio * available_memory) / 100;
-        }
+        else
+                dirty = (vm_dirty_ratio * available_memory) / 100;
 
         if (dirty_background_bytes)
                 background = DIV_ROUND_UP(dirty_background_bytes, PAGE_SIZE);
@@ -510,7 +507,7 @@ static void balance_dirty_pages(struct address_space *mapping,
                  * catch-up. This avoids (excessively) small writeouts
                  * when the bdi limits are ramping up.
                  */
-                if (nr_reclaimable + nr_writeback <
+                if (nr_reclaimable + nr_writeback <=
                                 (background_thresh + dirty_thresh) / 2)
                         break;
 
@@ -542,8 +539,8 @@ static void balance_dirty_pages(struct address_space *mapping,
                  * the last resort safeguard.
                  */
                 dirty_exceeded =
-                        (bdi_nr_reclaimable + bdi_nr_writeback >= bdi_thresh)
-                        || (nr_reclaimable + nr_writeback >= dirty_thresh);
+                        (bdi_nr_reclaimable + bdi_nr_writeback > bdi_thresh)
+                        || (nr_reclaimable + nr_writeback > dirty_thresh);
 
                 if (!dirty_exceeded)
                         break;
@@ -569,7 +566,7 @@ static void balance_dirty_pages(struct address_space *mapping,
                                 break;          /* We've done our duty */
                 }
                 trace_wbc_balance_dirty_wait(&wbc, bdi);
-                __set_current_state(TASK_INTERRUPTIBLE);
+                __set_current_state(TASK_UNINTERRUPTIBLE);
                 io_schedule_timeout(pause);
 
                 /*
@@ -930,7 +927,7 @@ retry:
                                 break;
                         }
 
-                        done_index = page->index + 1;
+                        done_index = page->index;
 
                         lock_page(page);
 
@@ -980,6 +977,7 @@ continue_unlock:
                                          * not be suitable for data integrity
                                          * writeout).
                                          */
+                                        done_index = page->index + 1;
                                         done = 1;
                                         break;
                                 }
@@ -1042,11 +1040,17 @@ static int __writepage(struct page *page, struct writeback_control *wbc,
 int generic_writepages(struct address_space *mapping,
                        struct writeback_control *wbc)
 {
+        struct blk_plug plug;
+        int ret;
+
         /* deal with chardevs and other special file */
         if (!mapping->a_ops->writepage)
                 return 0;
 
-        return write_cache_pages(mapping, wbc, __writepage, mapping);
+        blk_start_plug(&plug);
+        ret = write_cache_pages(mapping, wbc, __writepage, mapping);
+        blk_finish_plug(&plug);
+        return ret;
 }
 
 EXPORT_SYMBOL(generic_writepages);
@@ -1109,7 +1113,7 @@ EXPORT_SYMBOL(write_one_page);
 int __set_page_dirty_no_writeback(struct page *page)
 {
         if (!PageDirty(page))
-                SetPageDirty(page);
+                return !TestSetPageDirty(page);
         return 0;
 }
 
@@ -1121,6 +1125,7 @@ void account_page_dirtied(struct page *page, struct address_space *mapping)
 {
         if (mapping_cap_account_dirty(mapping)) {
                 __inc_zone_page_state(page, NR_FILE_DIRTY);
+                __inc_zone_page_state(page, NR_DIRTIED);
                 __inc_bdi_stat(mapping->backing_dev_info, BDI_RECLAIMABLE);
                 task_dirty_inc(current);
                 task_io_account_write(PAGE_CACHE_SIZE);
@@ -1129,6 +1134,18 @@ void account_page_dirtied(struct page *page, struct address_space *mapping)
 EXPORT_SYMBOL(account_page_dirtied);
 
 /*
+ * Helper function for set_page_writeback family.
+ * NOTE: Unlike account_page_dirtied this does not rely on being atomic
+ * wrt interrupts.
+ */
+void account_page_writeback(struct page *page)
+{
+        inc_zone_page_state(page, NR_WRITEBACK);
+        inc_zone_page_state(page, NR_WRITTEN);
+}
+EXPORT_SYMBOL(account_page_writeback);
+
+/*
  * For address_spaces which do not use buffers.  Just tag the page as dirty in
  * its radix tree.
  *
@@ -1201,6 +1218,17 @@ int set_page_dirty(struct page *page)
 
         if (likely(mapping)) {
                 int (*spd)(struct page *) = mapping->a_ops->set_page_dirty;
+                /*
+                 * readahead/lru_deactivate_page could remain
+                 * PG_readahead/PG_reclaim due to race with end_page_writeback
+                 * About readahead, if the page is written, the flags would be
+                 * reset. So no problem.
+                 * About lru_deactivate_page, if the page is redirty, the flag
+                 * will be reset. So no problem. but if the page is used by readahead
+                 * it will confuse readahead and make it restart the size rampup
+                 * process. But it's a trivial problem.
+                 */
+                ClearPageReclaim(page);
 #ifdef CONFIG_BLOCK
                 if (!spd)
                         spd = __set_page_dirty_buffers;
@@ -1229,7 +1257,7 @@ int set_page_dirty_lock(struct page *page)
 {
         int ret;
 
-        lock_page_nosync(page);
+        lock_page(page);
         ret = set_page_dirty(page);
         unlock_page(page);
         return ret;
@@ -1256,7 +1284,6 @@ int clear_page_dirty_for_io(struct page *page)
 
         BUG_ON(!PageLocked(page));
 
-        ClearPageReclaim(page);
         if (mapping && mapping_cap_account_dirty(mapping)) {
                 /*
                  * Yes, Virginia, this is indeed insane.
@@ -1366,7 +1393,7 @@ int test_set_page_writeback(struct page *page)
                 ret = TestSetPageWriteback(page);
         }
         if (!ret)
-                inc_zone_page_state(page, NR_WRITEBACK);
+                account_page_writeback(page);
         return ret;
 
 }