From 595043e5f9ef1d8263bd9fda215cade489227491 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Thu, 28 Sep 2017 11:26:59 -0600 Subject: [PATCH] writeback: provide a wakeup_flusher_threads_bdi() Similar to wakeup_flusher_threads(), except that we only wake up the flusher threads on the specified backing device. No functional changes in this patch. Acked-by: Johannes Weiner Tested-by: Chris Mason Reviewed-by: Jan Kara Reviewed-by: Christoph Hellwig Signed-off-by: Jens Axboe --- fs/fs-writeback.c | 39 +++++++++++++++++++++++++++++---------- include/linux/writeback.h | 2 ++ 2 files changed, 31 insertions(+), 10 deletions(-) diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index fe555bce886c..9f39829459dc 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -1946,6 +1946,33 @@ void wb_workfn(struct work_struct *work) current->flags &= ~PF_SWAPWRITE; } +/* + * Start writeback of `nr_pages' pages on this bdi. If `nr_pages' is zero, + * write back the whole world. + */ +static void __wakeup_flusher_threads_bdi(struct backing_dev_info *bdi, + long nr_pages, enum wb_reason reason) +{ + struct bdi_writeback *wb; + + if (!bdi_has_dirty_io(bdi)) + return; + + list_for_each_entry_rcu(wb, &bdi->wb_list, bdi_node) + wb_start_writeback(wb, wb_split_bdi_pages(wb, nr_pages), + reason); +} + +void wakeup_flusher_threads_bdi(struct backing_dev_info *bdi, + enum wb_reason reason) +{ + long nr_pages = get_nr_dirty_pages(); + + rcu_read_lock(); + __wakeup_flusher_threads_bdi(bdi, nr_pages, reason); + rcu_read_unlock(); +} + /* * Wakeup the flusher threads to start writeback of all currently dirty pages */ @@ -1963,16 +1990,8 @@ void wakeup_flusher_threads(enum wb_reason reason) nr_pages = get_nr_dirty_pages(); rcu_read_lock(); - list_for_each_entry_rcu(bdi, &bdi_list, bdi_list) { - struct bdi_writeback *wb; - - if (!bdi_has_dirty_io(bdi)) - continue; - - list_for_each_entry_rcu(wb, &bdi->wb_list, bdi_node) - wb_start_writeback(wb, wb_split_bdi_pages(wb, nr_pages), - reason); - } + list_for_each_entry_rcu(bdi, &bdi_list, bdi_list) + __wakeup_flusher_threads_bdi(bdi, nr_pages, reason); rcu_read_unlock(); } diff --git a/include/linux/writeback.h b/include/linux/writeback.h index 1f9c6db5e29a..9c0091678af4 100644 --- a/include/linux/writeback.h +++ b/include/linux/writeback.h @@ -190,6 +190,8 @@ bool try_to_writeback_inodes_sb_nr(struct super_block *, unsigned long nr, enum wb_reason reason); void sync_inodes_sb(struct super_block *); void wakeup_flusher_threads(enum wb_reason reason); +void wakeup_flusher_threads_bdi(struct backing_dev_info *bdi, + enum wb_reason reason); void inode_wait_for_writeback(struct inode *inode); /* writeback.h requires fs.h; it, too, is not included from here. */