Merge branch 'writeback' of git://git.kernel.dk/linux-2.6-block
[pandora-kernel.git] / mm / page-writeback.c
index 1eea4fa..69b5fba 100644 (file)
@@ -44,18 +44,21 @@ static long ratelimit_pages = 32;
 /*
  * When balance_dirty_pages decides that the caller needs to perform some
  * non-background writeback, this is how many pages it will attempt to write.
- * It should be somewhat larger than RATELIMIT_PAGES to ensure that reasonably
+ * It should be somewhat larger than dirtied pages to ensure that reasonably
  * large amounts of I/O are submitted.
  */
-static inline long sync_writeback_pages(void)
+static inline long sync_writeback_pages(unsigned long dirtied)
 {
-       return ratelimit_pages + ratelimit_pages / 2;
+       if (dirtied < ratelimit_pages)
+               dirtied = ratelimit_pages;
+
+       return dirtied + dirtied / 2;
 }
 
 /* The following parameters are exported via /proc/sys/vm */
 
 /*
- * Start background writeback (via pdflush) at this percentage
+ * Start background writeback (via writeback threads) at this percentage
  */
 int dirty_background_ratio = 10;
 
@@ -155,37 +158,37 @@ static void update_completion_period(void)
 }
 
 int dirty_background_ratio_handler(struct ctl_table *table, int write,
-               struct file *filp, void __user *buffer, size_t *lenp,
+               void __user *buffer, size_t *lenp,
                loff_t *ppos)
 {
        int ret;
 
-       ret = proc_dointvec_minmax(table, write, filp, buffer, lenp, ppos);
+       ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
        if (ret == 0 && write)
                dirty_background_bytes = 0;
        return ret;
 }
 
 int dirty_background_bytes_handler(struct ctl_table *table, int write,
-               struct file *filp, void __user *buffer, size_t *lenp,
+               void __user *buffer, size_t *lenp,
                loff_t *ppos)
 {
        int ret;
 
-       ret = proc_doulongvec_minmax(table, write, filp, buffer, lenp, ppos);
+       ret = proc_doulongvec_minmax(table, write, buffer, lenp, ppos);
        if (ret == 0 && write)
                dirty_background_ratio = 0;
        return ret;
 }
 
 int dirty_ratio_handler(struct ctl_table *table, int write,
-               struct file *filp, void __user *buffer, size_t *lenp,
+               void __user *buffer, size_t *lenp,
                loff_t *ppos)
 {
        int old_ratio = vm_dirty_ratio;
        int ret;
 
-       ret = proc_dointvec_minmax(table, write, filp, buffer, lenp, ppos);
+       ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
        if (ret == 0 && write && vm_dirty_ratio != old_ratio) {
                update_completion_period();
                vm_dirty_bytes = 0;
@@ -195,13 +198,13 @@ int dirty_ratio_handler(struct ctl_table *table, int write,
 
 
 int dirty_bytes_handler(struct ctl_table *table, int write,
-               struct file *filp, void __user *buffer, size_t *lenp,
+               void __user *buffer, size_t *lenp,
                loff_t *ppos)
 {
        unsigned long old_bytes = vm_dirty_bytes;
        int ret;
 
-       ret = proc_doulongvec_minmax(table, write, filp, buffer, lenp, ppos);
+       ret = proc_doulongvec_minmax(table, write, buffer, lenp, ppos);
        if (ret == 0 && write && vm_dirty_bytes != old_bytes) {
                update_completion_period();
                vm_dirty_ratio = 0;
@@ -380,7 +383,8 @@ static unsigned long highmem_dirtyable_memory(unsigned long total)
                struct zone *z =
                        &NODE_DATA(node)->node_zones[ZONE_HIGHMEM];
 
-               x += zone_page_state(z, NR_FREE_PAGES) + zone_lru_pages(z);
+               x += zone_page_state(z, NR_FREE_PAGES) +
+                    zone_reclaimable_pages(z);
        }
        /*
         * Make sure that the number of highmem pages is never larger
@@ -404,7 +408,7 @@ unsigned long determine_dirtyable_memory(void)
 {
        unsigned long x;
 
-       x = global_page_state(NR_FREE_PAGES) + global_lru_pages();
+       x = global_page_state(NR_FREE_PAGES) + global_reclaimable_pages();
 
        if (!vm_highmem_is_dirtyable)
                x -= highmem_dirtyable_memory(x);
@@ -473,10 +477,11 @@ get_dirty_limits(unsigned long *pbackground, unsigned long *pdirty,
  * balance_dirty_pages() must be called by processes which are generating dirty
  * data.  It looks at the number of dirty pages in the machine and will force
  * the caller to perform writeback if the system is over `vm_dirty_ratio'.
- * If we're over `background_thresh' then pdflush is woken to perform some
- * writeout.
+ * If we're over `background_thresh' then the writeback threads are woken to
+ * perform some writeout.
  */
-static void balance_dirty_pages(struct address_space *mapping)
+static void balance_dirty_pages(struct address_space *mapping,
+                               unsigned long write_chunk)
 {
        long nr_reclaimable, bdi_nr_reclaimable;
        long nr_writeback, bdi_nr_writeback;
@@ -484,7 +489,7 @@ static void balance_dirty_pages(struct address_space *mapping)
        unsigned long dirty_thresh;
        unsigned long bdi_thresh;
        unsigned long pages_written = 0;
-       unsigned long write_chunk = sync_writeback_pages();
+       unsigned long pause = 1;
 
        struct backing_dev_info *bdi = mapping->backing_dev_info;
 
@@ -561,7 +566,15 @@ static void balance_dirty_pages(struct address_space *mapping)
                if (pages_written >= write_chunk)
                        break;          /* We've done our duty */
 
-               schedule_timeout(1);
+               schedule_timeout_interruptible(pause);
+
+               /*
+                * Increase the delay for each loop, up to our previous
+                * default of taking a 100ms nap.
+                */
+               pause <<= 1;
+               if (pause > HZ / 10)
+                       pause = HZ / 10;
        }
 
        if (bdi_nr_reclaimable + bdi_nr_writeback < bdi_thresh &&
@@ -569,7 +582,7 @@ static void balance_dirty_pages(struct address_space *mapping)
                bdi->dirty_exceeded = 0;
 
        if (writeback_in_progress(bdi))
-               return;         /* pdflush is already working this queue */
+               return;
 
        /*
         * In laptop mode, we wait until hitting the higher threshold before
@@ -580,10 +593,10 @@ static void balance_dirty_pages(struct address_space *mapping)
         * background_thresh, to keep the amount of dirty memory low.
         */
        if ((laptop_mode && pages_written) ||
-           (!laptop_mode && ((nr_writeback = global_page_state(NR_FILE_DIRTY)
-                                         + global_page_state(NR_UNSTABLE_NFS))
+           (!laptop_mode && ((global_page_state(NR_FILE_DIRTY)
+                              + global_page_state(NR_UNSTABLE_NFS))
                                          > background_thresh)))
-               bdi_start_writeback(bdi, nr_writeback);
+               bdi_start_writeback(bdi, 0);
 }
 
 void set_page_dirty_balance(struct page *page, int page_mkwrite)
@@ -630,9 +643,10 @@ void balance_dirty_pages_ratelimited_nr(struct address_space *mapping,
        p =  &__get_cpu_var(bdp_ratelimits);
        *p += nr_pages_dirtied;
        if (unlikely(*p >= ratelimit)) {
+               ratelimit = sync_writeback_pages(*p);
                *p = 0;
                preempt_enable();
-               balance_dirty_pages(mapping);
+               balance_dirty_pages(mapping, ratelimit);
                return;
        }
        preempt_enable();
@@ -676,9 +690,9 @@ static DEFINE_TIMER(laptop_mode_wb_timer, laptop_timer_fn, 0, 0);
  * sysctl handler for /proc/sys/vm/dirty_writeback_centisecs
  */
 int dirty_writeback_centisecs_handler(ctl_table *table, int write,
-       struct file *file, void __user *buffer, size_t *length, loff_t *ppos)
+       void __user *buffer, size_t *length, loff_t *ppos)
 {
-       proc_dointvec(table, write, file, buffer, length, ppos);
+       proc_dointvec(table, write, buffer, length, ppos);
        return 0;
 }
 
@@ -1139,6 +1153,13 @@ int redirty_page_for_writepage(struct writeback_control *wbc, struct page *page)
 EXPORT_SYMBOL(redirty_page_for_writepage);
 
 /*
+ * Dirty a page.
+ *
+ * For pages with a mapping this should be done under the page lock
+ * for the benefit of asynchronous memory errors who prefer a consistent
+ * dirty state. This rule can be broken in some special cases,
+ * but should be better not to.
+ *
  * If the mapping doesn't provide a set_page_dirty a_op, then
  * just fall through and assume that it wants buffer_heads.
  */