diff options
| -rw-r--r-- | fs/fs-writeback.c | 61 |
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(); } |