[PATCH] fadvise(): write commands

[linux-2.6] / mm / page-writeback.c

diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 5240e426c1f771d24febb3ac60c8b375e794d28d..c1052ee79f01096d6dfe23f8d1021c80216b3ad5 100644 (file)
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -46,7 +46,7 @@
 static long ratelimit_pages = 32;
 
 static long total_pages;       /* The total number of pages in the machine. */
-static int dirty_exceeded;     /* Dirty mem may be over limit */
+static int dirty_exceeded __cacheline_aligned_in_smp;  /* Dirty mem may be over limit */
 
 /*
  * When balance_dirty_pages decides that the caller needs to perform some
@@ -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;
 
@@ -212,7 +213,8 @@ static void balance_dirty_pages(struct address_space *mapping)
                if (nr_reclaimable + wbs.nr_writeback <= dirty_thresh)
                        break;
 
-               dirty_exceeded = 1;
+               if (!dirty_exceeded)
+                       dirty_exceeded = 1;
 
                /* Note: nr_reclaimable denotes nr_dirty + nr_unstable.
                 * Unstable writes are a feature of certain networked
@@ -234,7 +236,7 @@ static void balance_dirty_pages(struct address_space *mapping)
                blk_congestion_wait(WRITE, HZ/10);
        }
 
-       if (nr_reclaimable + wbs.nr_writeback <= dirty_thresh)
+       if (nr_reclaimable + wbs.nr_writeback <= dirty_thresh && dirty_exceeded)
                dirty_exceeded = 0;
 
        if (writeback_in_progress(bdi))
@@ -379,8 +381,8 @@ 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
@@ -405,9 +407,9 @@ 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) {
@@ -424,7 +426,7 @@ 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);
 }
 
@@ -434,11 +436,11 @@ 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;
@@ -467,7 +469,7 @@ 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);
 }
 
 /*
@@ -543,7 +545,7 @@ 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);
 }