1 files changed, 36 insertions, 28 deletions

diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 945559fb63d2..893d7677579e 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -75,12 +75,12 @@ int vm_dirty_ratio = 40;
  * The interval between `kupdate'-style writebacks, in centiseconds
  * (hundredths of a second)
  */
-int dirty_writeback_centisecs = 5 * 100;
+int dirty_writeback_interval = 5 * HZ;
 
 /*
  * The longest number of centiseconds for which data is allowed to remain dirty
  */
-int dirty_expire_centisecs = 30 * 100;
+int dirty_expire_interval = 30 * HZ;
 
 /*
  * Flag that makes the machine dump writes/reads and block dirtyings.
@@ -88,7 +88,8 @@ int dirty_expire_centisecs = 30 * 100;
 int block_dump;
 
 /*
- * Flag that puts the machine in "laptop mode".
+ * Flag that puts the machine in "laptop mode". Doubles as a timeout in jiffies:
+ * a full sync is triggered after this time elapses without any disk activity.
  */
 int laptop_mode;
 
@@ -255,8 +256,9 @@ static void balance_dirty_pages(struct address_space *mapping)
 }
 
 /**
- * balance_dirty_pages_ratelimited - balance dirty memory state
+ * balance_dirty_pages_ratelimited_nr - balance dirty memory state
  * @mapping: address_space which was dirtied
+ * @nr_pages: number of pages which the caller has just dirtied
  *
  * Processes which are dirtying memory should call in here once for each page
  * which was newly dirtied.  The function will periodically check the system's
@@ -267,10 +269,12 @@ static void balance_dirty_pages(struct address_space *mapping)
  * limit we decrease the ratelimiting by a lot, to prevent individual processes
  * from overshooting the limit by (ratelimit_pages) each.
  */
-void balance_dirty_pages_ratelimited(struct address_space *mapping)
+void balance_dirty_pages_ratelimited_nr(struct address_space *mapping,
+                                        unsigned long nr_pages_dirtied)
 {
-        static DEFINE_PER_CPU(int, ratelimits) = 0;
-        long ratelimit;
+        static DEFINE_PER_CPU(unsigned long, ratelimits) = 0;
+        unsigned long ratelimit;
+        unsigned long *p;
 
         ratelimit = ratelimit_pages;
         if (dirty_exceeded)
@@ -280,15 +284,18 @@ void balance_dirty_pages_ratelimited(struct address_space *mapping)
          * Check the rate limiting. Also, we do not want to throttle real-time
          * tasks in balance_dirty_pages(). Period.
          */
-        if (get_cpu_var(ratelimits)++ >= ratelimit) {
-                __get_cpu_var(ratelimits) = 0;
-                put_cpu_var(ratelimits);
+        preempt_disable();
+        p =  &__get_cpu_var(ratelimits);
+        *p += nr_pages_dirtied;
+        if (unlikely(*p >= ratelimit)) {
+                *p = 0;
+                preempt_enable();
                 balance_dirty_pages(mapping);
                 return;
         }
-        put_cpu_var(ratelimits);
+        preempt_enable();
 }
-EXPORT_SYMBOL(balance_dirty_pages_ratelimited);
+EXPORT_SYMBOL(balance_dirty_pages_ratelimited_nr);
 
 void throttle_vm_writeout(void)
 {
@@ -380,8 +387,8 @@ static DEFINE_TIMER(laptop_mode_wb_timer, laptop_timer_fn, 0, 0);
  * just walks the superblock inode list, writing back any inodes which are
  * older than a specific point in time.
  *
- * Try to run once per dirty_writeback_centisecs.  But if a writeback event
- * takes longer than a dirty_writeback_centisecs interval, then leave a
+ * Try to run once per dirty_writeback_interval.  But if a writeback event
+ * takes longer than a dirty_writeback_interval interval, then leave a
  * one-second gap.
  *
  * older_than_this takes precedence over nr_to_write.  So we'll only write back
@@ -406,9 +413,9 @@ static void wb_kupdate(unsigned long arg)
         sync_supers();
 
         get_writeback_state(&wbs);
-        oldest_jif = jiffies - (dirty_expire_centisecs * HZ) / 100;
+        oldest_jif = jiffies - dirty_expire_interval;
         start_jif = jiffies;
-        next_jif = start_jif + (dirty_writeback_centisecs * HZ) / 100;
+        next_jif = start_jif + dirty_writeback_interval;
         nr_to_write = wbs.nr_dirty + wbs.nr_unstable +
                         (inodes_stat.nr_inodes - inodes_stat.nr_unused);
         while (nr_to_write > 0) {
@@ -425,7 +432,7 @@ static void wb_kupdate(unsigned long arg)
         }
         if (time_before(next_jif, jiffies + HZ))
                 next_jif = jiffies + HZ;
-        if (dirty_writeback_centisecs)
+        if (dirty_writeback_interval)
                 mod_timer(&wb_timer, next_jif);
 }
 
@@ -435,11 +442,11 @@ static void wb_kupdate(unsigned long arg)
 int dirty_writeback_centisecs_handler(ctl_table *table, int write,
                 struct file *file, void __user *buffer, size_t *length, loff_t *ppos)
 {
-        proc_dointvec(table, write, file, buffer, length, ppos);
-        if (dirty_writeback_centisecs) {
+        proc_dointvec_userhz_jiffies(table, write, file, buffer, length, ppos);
+        if (dirty_writeback_interval) {
                 mod_timer(&wb_timer,
-                        jiffies + (dirty_writeback_centisecs * HZ) / 100);
-        } else {
+                        jiffies + dirty_writeback_interval);
+                } else {
                 del_timer(&wb_timer);
         }
         return 0;
@@ -468,7 +475,7 @@ static void laptop_timer_fn(unsigned long unused)
  */
 void laptop_io_completion(void)
 {
-        mod_timer(&laptop_mode_wb_timer, jiffies + laptop_mode * HZ);
+        mod_timer(&laptop_mode_wb_timer, jiffies + laptop_mode);
 }
 
 /*
@@ -544,7 +551,7 @@ void __init page_writeback_init(void)
                 if (vm_dirty_ratio <= 0)
                         vm_dirty_ratio = 1;
         }
-        mod_timer(&wb_timer, jiffies + (dirty_writeback_centisecs * HZ) / 100);
+        mod_timer(&wb_timer, jiffies + dirty_writeback_interval);
         set_ratelimit();
         register_cpu_notifier(&ratelimit_nb);
 }
@@ -621,8 +628,6 @@ EXPORT_SYMBOL(write_one_page);
  */
 int __set_page_dirty_nobuffers(struct page *page)
 {
-        int ret = 0;
-
         if (!TestSetPageDirty(page)) {
                 struct address_space *mapping = page_mapping(page);
                 struct address_space *mapping2;
@@ -644,8 +649,9 @@ int __set_page_dirty_nobuffers(struct page *page)
                                                         I_DIRTY_PAGES);
                         }
                 }
+                return 1;
         }
-        return ret;
+        return 0;
 }
 EXPORT_SYMBOL(__set_page_dirty_nobuffers);
 
@@ -675,8 +681,10 @@ int fastcall set_page_dirty(struct page *page)
                         return (*spd)(page);
                 return __set_page_dirty_buffers(page);
         }
-        if (!PageDirty(page))
-                SetPageDirty(page);
+        if (!PageDirty(page)) {
+                if (!TestSetPageDirty(page))
+                        return 1;
+        }
         return 0;
 }
 EXPORT_SYMBOL(set_page_dirty);