1 files changed, 34 insertions, 51 deletions

diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index de9836f43db5..e630188ccc40 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -99,23 +99,6 @@ EXPORT_SYMBOL(laptop_mode);
 
 static void background_writeout(unsigned long _min_pages);
 
-struct writeback_state
-{
-        unsigned long nr_dirty;
-        unsigned long nr_unstable;
-        unsigned long nr_mapped;
-        unsigned long nr_writeback;
-};
-
-static void get_writeback_state(struct writeback_state *wbs)
-{
-        wbs->nr_dirty = global_page_state(NR_FILE_DIRTY);
-        wbs->nr_unstable = global_page_state(NR_UNSTABLE_NFS);
-        wbs->nr_mapped = global_page_state(NR_FILE_MAPPED) +
-                                global_page_state(NR_ANON_PAGES);
-        wbs->nr_writeback = global_page_state(NR_WRITEBACK);
-}
-
 /*
  * Work out the current dirty-memory clamping and background writeout
  * thresholds.
@@ -134,8 +117,8 @@ static void get_writeback_state(struct writeback_state *wbs)
  * clamping level.
  */
 static void
-get_dirty_limits(struct writeback_state *wbs, long *pbackground, long *pdirty,
-                struct address_space *mapping)
+get_dirty_limits(long *pbackground, long *pdirty,
+                                        struct address_space *mapping)
 {
         int background_ratio;           /* Percentages */
         int dirty_ratio;
@@ -145,8 +128,6 @@ get_dirty_limits(struct writeback_state *wbs, long *pbackground, long *pdirty,
         unsigned long available_memory = total_pages;
         struct task_struct *tsk;
 
-        get_writeback_state(wbs);
-
 #ifdef CONFIG_HIGHMEM
         /*
          * If this mapping can only allocate from low memory,
@@ -157,7 +138,9 @@ get_dirty_limits(struct writeback_state *wbs, long *pbackground, long *pdirty,
 #endif
 
 
-        unmapped_ratio = 100 - (wbs->nr_mapped * 100) / total_pages;
+        unmapped_ratio = 100 - ((global_page_state(NR_FILE_MAPPED) +
+                                global_page_state(NR_ANON_PAGES)) * 100) /
+                                        total_pages;
 
         dirty_ratio = vm_dirty_ratio;
         if (dirty_ratio > unmapped_ratio / 2)
@@ -190,7 +173,6 @@ get_dirty_limits(struct writeback_state *wbs, long *pbackground, long *pdirty,
  */
 static void balance_dirty_pages(struct address_space *mapping)
 {
-        struct writeback_state wbs;
         long nr_reclaimable;
         long background_thresh;
         long dirty_thresh;
@@ -208,11 +190,12 @@ static void balance_dirty_pages(struct address_space *mapping)
                         .range_cyclic   = 1,
                 };
 
-                get_dirty_limits(&wbs, &background_thresh,
-                                        &dirty_thresh, mapping);
-                nr_reclaimable = wbs.nr_dirty + wbs.nr_unstable;
-                if (nr_reclaimable + wbs.nr_writeback <= dirty_thresh)
-                        break;
+                get_dirty_limits(&background_thresh, &dirty_thresh, mapping);
+                nr_reclaimable = global_page_state(NR_FILE_DIRTY) +
+                                        global_page_state(NR_UNSTABLE_NFS);
+                if (nr_reclaimable + global_page_state(NR_WRITEBACK) <=
+                        dirty_thresh)
+                                break;
 
                 if (!dirty_exceeded)
                         dirty_exceeded = 1;
@@ -225,11 +208,14 @@ static void balance_dirty_pages(struct address_space *mapping)
                  */
                 if (nr_reclaimable) {
                         writeback_inodes(&wbc);
-                        get_dirty_limits(&wbs, &background_thresh,
-                                        &dirty_thresh, mapping);
-                        nr_reclaimable = wbs.nr_dirty + wbs.nr_unstable;
-                        if (nr_reclaimable + wbs.nr_writeback <= dirty_thresh)
-                                break;
+                        get_dirty_limits(&background_thresh,
+                                                &dirty_thresh, mapping);
+                        nr_reclaimable = global_page_state(NR_FILE_DIRTY) +
+                                        global_page_state(NR_UNSTABLE_NFS);
+                        if (nr_reclaimable +
+                                global_page_state(NR_WRITEBACK)
+                                        <= dirty_thresh)
+                                                break;
                         pages_written += write_chunk - wbc.nr_to_write;
                         if (pages_written >= write_chunk)
                                 break;          /* We've done our duty */
@@ -237,8 +223,9 @@ static void balance_dirty_pages(struct address_space *mapping)
                 blk_congestion_wait(WRITE, HZ/10);
         }
 
-        if (nr_reclaimable + wbs.nr_writeback <= dirty_thresh && dirty_exceeded)
-                dirty_exceeded = 0;
+        if (nr_reclaimable + global_page_state(NR_WRITEBACK)
+                <= dirty_thresh && dirty_exceeded)
+                        dirty_exceeded = 0;
 
         if (writeback_in_progress(bdi))
                 return;         /* pdflush is already working this queue */
@@ -300,12 +287,11 @@ EXPORT_SYMBOL(balance_dirty_pages_ratelimited_nr);
 
 void throttle_vm_writeout(void)
 {
-        struct writeback_state wbs;
         long background_thresh;
         long dirty_thresh;
 
         for ( ; ; ) {
-                get_dirty_limits(&wbs, &background_thresh, &dirty_thresh, NULL);
+                get_dirty_limits(&background_thresh, &dirty_thresh, NULL);
 
                 /*
                  * Boost the allowable dirty threshold a bit for page
@@ -313,8 +299,9 @@ void throttle_vm_writeout(void)
                  */
                 dirty_thresh += dirty_thresh / 10;      /* wheeee... */
 
-                if (wbs.nr_unstable + wbs.nr_writeback <= dirty_thresh)
-                        break;
+                if (global_page_state(NR_UNSTABLE_NFS) +
+                        global_page_state(NR_WRITEBACK) <= dirty_thresh)
+                                break;
                 blk_congestion_wait(WRITE, HZ/10);
         }
 }
@@ -337,12 +324,12 @@ static void background_writeout(unsigned long _min_pages)
         };
 
         for ( ; ; ) {
-                struct writeback_state wbs;
                 long background_thresh;
                 long dirty_thresh;
 
-                get_dirty_limits(&wbs, &background_thresh, &dirty_thresh, NULL);
-                if (wbs.nr_dirty + wbs.nr_unstable < background_thresh
+                get_dirty_limits(&background_thresh, &dirty_thresh, NULL);
+                if (global_page_state(NR_FILE_DIRTY) +
+                        global_page_state(NR_UNSTABLE_NFS) < background_thresh
                                 && min_pages <= 0)
                         break;
                 wbc.encountered_congestion = 0;
@@ -366,12 +353,9 @@ static void background_writeout(unsigned long _min_pages)
  */
 int wakeup_pdflush(long nr_pages)
 {
-        if (nr_pages == 0) {
-                struct writeback_state wbs;
-
-                get_writeback_state(&wbs);
-                nr_pages = wbs.nr_dirty + wbs.nr_unstable;
-        }
+        if (nr_pages == 0)
+                nr_pages = global_page_state(NR_FILE_DIRTY) +
+                                global_page_state(NR_UNSTABLE_NFS);
         return pdflush_operation(background_writeout, nr_pages);
 }
 
@@ -402,7 +386,6 @@ static void wb_kupdate(unsigned long arg)
         unsigned long start_jif;
         unsigned long next_jif;
         long nr_to_write;
-        struct writeback_state wbs;
         struct writeback_control wbc = {
                 .bdi            = NULL,
                 .sync_mode      = WB_SYNC_NONE,
@@ -415,11 +398,11 @@ static void wb_kupdate(unsigned long arg)
 
         sync_supers();
 
-        get_writeback_state(&wbs);
         oldest_jif = jiffies - dirty_expire_interval;
         start_jif = jiffies;
         next_jif = start_jif + dirty_writeback_interval;
-        nr_to_write = wbs.nr_dirty + wbs.nr_unstable +
+        nr_to_write = global_page_state(NR_FILE_DIRTY) +
+                        global_page_state(NR_UNSTABLE_NFS) +
                         (inodes_stat.nr_inodes - inodes_stat.nr_unused);
         while (nr_to_write > 0) {
                 wbc.encountered_congestion = 0;