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-rw-r--r--fs/fs-writeback.c61
1 files changed, 46 insertions, 15 deletions
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 3d06ccc..3a07f6d 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -84,13 +84,9 @@ static inline struct inode *wb_inode(struct list_head *head)
return list_entry(head, struct inode, i_wb_list);
}
-static void bdi_queue_work(struct backing_dev_info *bdi,
- struct wb_writeback_work *work)
+/* Wakeup flusher thread or forker thread to fork it. Requires bdi->wb_lock. */
+static void bdi_wakeup_flusher(struct backing_dev_info *bdi)
{
- trace_writeback_queue(bdi, work);
-
- spin_lock_bh(&bdi->wb_lock);
- list_add_tail(&work->list, &bdi->work_list);
if (bdi->wb.task) {
wake_up_process(bdi->wb.task);
} else {
@@ -98,15 +94,26 @@ static void bdi_queue_work(struct backing_dev_info *bdi,
* The bdi thread isn't there, wake up the forker thread which
* will create and run it.
*/
- trace_writeback_nothread(bdi, work);
wake_up_process(default_backing_dev_info.wb.task);
}
+}
+
+static void bdi_queue_work(struct backing_dev_info *bdi,
+ struct wb_writeback_work *work)
+{
+ trace_writeback_queue(bdi, work);
+
+ spin_lock_bh(&bdi->wb_lock);
+ list_add_tail(&work->list, &bdi->work_list);
+ if (!bdi->wb.task)
+ trace_writeback_nothread(bdi, work);
+ bdi_wakeup_flusher(bdi);
spin_unlock_bh(&bdi->wb_lock);
}
static void
__bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages,
- bool range_cyclic, bool for_background)
+ bool range_cyclic)
{
struct wb_writeback_work *work;
@@ -126,7 +133,6 @@ __bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages,
work->sync_mode = WB_SYNC_NONE;
work->nr_pages = nr_pages;
work->range_cyclic = range_cyclic;
- work->for_background = for_background;
bdi_queue_work(bdi, work);
}
@@ -144,7 +150,7 @@ __bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages,
*/
void bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages)
{
- __bdi_start_writeback(bdi, nr_pages, true, false);
+ __bdi_start_writeback(bdi, nr_pages, true);
}
/**
@@ -152,13 +158,20 @@ void bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages)
* @bdi: the backing device to write from
*
* Description:
- * This does WB_SYNC_NONE background writeback. The IO is only
- * started when this function returns, we make no guarentees on
- * completion. Caller need not hold sb s_umount semaphore.
+ * This makes sure WB_SYNC_NONE background writeback happens. When
+ * this function returns, it is only guaranteed that for given BDI
+ * some IO is happening if we are over background dirty threshold.
+ * Caller need not hold sb s_umount semaphore.
*/
void bdi_start_background_writeback(struct backing_dev_info *bdi)
{
- __bdi_start_writeback(bdi, LONG_MAX, true, true);
+ /*
+ * We just wake up the flusher thread. It will perform background
+ * writeback as soon as there is no other work to do.
+ */
+ spin_lock_bh(&bdi->wb_lock);
+ bdi_wakeup_flusher(bdi);
+ spin_unlock_bh(&bdi->wb_lock);
}
/*
@@ -718,6 +731,23 @@ static unsigned long get_nr_dirty_pages(void)
get_nr_dirty_inodes();
}
+static long wb_check_background_flush(struct bdi_writeback *wb)
+{
+ if (over_bground_thresh()) {
+
+ struct wb_writeback_work work = {
+ .nr_pages = LONG_MAX,
+ .sync_mode = WB_SYNC_NONE,
+ .for_background = 1,
+ .range_cyclic = 1,
+ };
+
+ return wb_writeback(wb, &work);
+ }
+
+ return 0;
+}
+
static long wb_check_old_data_flush(struct bdi_writeback *wb)
{
unsigned long expired;
@@ -787,6 +817,7 @@ long wb_do_writeback(struct bdi_writeback *wb, int force_wait)
* Check for periodic writeback, kupdated() style
*/
wrote += wb_check_old_data_flush(wb);
+ wrote += wb_check_background_flush(wb);
clear_bit(BDI_writeback_running, &wb->bdi->state);
return wrote;
@@ -873,7 +904,7 @@ void wakeup_flusher_threads(long nr_pages)
list_for_each_entry_rcu(bdi, &bdi_list, bdi_list) {
if (!bdi_has_dirty_io(bdi))
continue;
- __bdi_start_writeback(bdi, nr_pages, false, false);
+ __bdi_start_writeback(bdi, nr_pages, false);
}
rcu_read_unlock();
}
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