From f0054bb1e1f3be03cc33369df640db97f10f6172 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Fri, 22 May 2015 17:13:30 -0400 Subject: writeback: move backing_dev_info->wb_lock and ->worklist into bdi_writeback Currently, a bdi (backing_dev_info) embeds single wb (bdi_writeback) and the role of the separation is unclear. For cgroup support for writeback IOs, a bdi will be updated to host multiple wb's where each wb serves writeback IOs of a different cgroup on the bdi. To achieve that, a wb should carry all states necessary for servicing writeback IOs for a cgroup independently. This patch moves bdi->wb_lock and ->worklist into wb. * The lock protects bdi->worklist and bdi->wb.dwork scheduling. While moving, rename it to wb->work_lock as wb->wb_lock is confusing. Also, move wb->dwork downwards so that it's colocated with the new ->work_lock and ->work_list fields. * bdi_writeback_workfn() -> wb_workfn() bdi_wakeup_thread_delayed(bdi) -> wb_wakeup_delayed(wb) bdi_wakeup_thread(bdi) -> wb_wakeup(wb) bdi_queue_work(bdi, ...) -> wb_queue_work(wb, ...) __bdi_start_writeback(bdi, ...) -> __wb_start_writeback(wb, ...) get_next_work_item(bdi) -> get_next_work_item(wb) * bdi_wb_shutdown() is renamed to wb_shutdown() and now takes @wb. The function contained parts which belong to the containing bdi rather than the wb itself - testing cap_writeback_dirty and bdi_remove_from_list() invocation. Those are moved to bdi_unregister(). * bdi_wb_{init|exit}() are renamed to wb_{init|exit}(). Initializations of the moved bdi->wb_lock and ->work_list are relocated from bdi_init() to wb_init(). * As there's still only one bdi_writeback per backing_dev_info, all uses of bdi->state are mechanically replaced with bdi->wb.state introducing no behavior changes. Signed-off-by: Tejun Heo Reviewed-by: Jan Kara Cc: Jens Axboe Cc: Wu Fengguang Signed-off-by: Jens Axboe --- fs/fs-writeback.c | 86 ++++++++++++++++++++++++++----------------------------- 1 file changed, 41 insertions(+), 45 deletions(-) (limited to 'fs/fs-writeback.c') diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index 1945cb9f6b97..a69d2e10d514 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -109,34 +109,33 @@ static inline struct inode *wb_inode(struct list_head *head) EXPORT_TRACEPOINT_SYMBOL_GPL(wbc_writepage); -static void bdi_wakeup_thread(struct backing_dev_info *bdi) +static void wb_wakeup(struct bdi_writeback *wb) { - spin_lock_bh(&bdi->wb_lock); - if (test_bit(WB_registered, &bdi->wb.state)) - mod_delayed_work(bdi_wq, &bdi->wb.dwork, 0); - spin_unlock_bh(&bdi->wb_lock); + spin_lock_bh(&wb->work_lock); + if (test_bit(WB_registered, &wb->state)) + mod_delayed_work(bdi_wq, &wb->dwork, 0); + spin_unlock_bh(&wb->work_lock); } -static void bdi_queue_work(struct backing_dev_info *bdi, - struct wb_writeback_work *work) +static void wb_queue_work(struct bdi_writeback *wb, + struct wb_writeback_work *work) { - trace_writeback_queue(bdi, work); + trace_writeback_queue(wb->bdi, work); - spin_lock_bh(&bdi->wb_lock); - if (!test_bit(WB_registered, &bdi->wb.state)) { + spin_lock_bh(&wb->work_lock); + if (!test_bit(WB_registered, &wb->state)) { if (work->done) complete(work->done); goto out_unlock; } - list_add_tail(&work->list, &bdi->work_list); - mod_delayed_work(bdi_wq, &bdi->wb.dwork, 0); + list_add_tail(&work->list, &wb->work_list); + mod_delayed_work(bdi_wq, &wb->dwork, 0); out_unlock: - spin_unlock_bh(&bdi->wb_lock); + spin_unlock_bh(&wb->work_lock); } -static void -__bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages, - bool range_cyclic, enum wb_reason reason) +static void __wb_start_writeback(struct bdi_writeback *wb, long nr_pages, + bool range_cyclic, enum wb_reason reason) { struct wb_writeback_work *work; @@ -146,8 +145,8 @@ __bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages, */ work = kzalloc(sizeof(*work), GFP_ATOMIC); if (!work) { - trace_writeback_nowork(bdi); - bdi_wakeup_thread(bdi); + trace_writeback_nowork(wb->bdi); + wb_wakeup(wb); return; } @@ -156,7 +155,7 @@ __bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages, work->range_cyclic = range_cyclic; work->reason = reason; - bdi_queue_work(bdi, work); + wb_queue_work(wb, work); } /** @@ -174,7 +173,7 @@ __bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages, void bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages, enum wb_reason reason) { - __bdi_start_writeback(bdi, nr_pages, true, reason); + __wb_start_writeback(&bdi->wb, nr_pages, true, reason); } /** @@ -194,7 +193,7 @@ void bdi_start_background_writeback(struct backing_dev_info *bdi) * writeback as soon as there is no other work to do. */ trace_writeback_wake_background(bdi); - bdi_wakeup_thread(bdi); + wb_wakeup(&bdi->wb); } /* @@ -898,7 +897,7 @@ static long wb_writeback(struct bdi_writeback *wb, * after the other works are all done. */ if ((work->for_background || work->for_kupdate) && - !list_empty(&wb->bdi->work_list)) + !list_empty(&wb->work_list)) break; /* @@ -969,18 +968,17 @@ static long wb_writeback(struct bdi_writeback *wb, /* * Return the next wb_writeback_work struct that hasn't been processed yet. */ -static struct wb_writeback_work * -get_next_work_item(struct backing_dev_info *bdi) +static struct wb_writeback_work *get_next_work_item(struct bdi_writeback *wb) { struct wb_writeback_work *work = NULL; - spin_lock_bh(&bdi->wb_lock); - if (!list_empty(&bdi->work_list)) { - work = list_entry(bdi->work_list.next, + spin_lock_bh(&wb->work_lock); + if (!list_empty(&wb->work_list)) { + work = list_entry(wb->work_list.next, struct wb_writeback_work, list); list_del_init(&work->list); } - spin_unlock_bh(&bdi->wb_lock); + spin_unlock_bh(&wb->work_lock); return work; } @@ -1052,14 +1050,13 @@ static long wb_check_old_data_flush(struct bdi_writeback *wb) */ static long wb_do_writeback(struct bdi_writeback *wb) { - struct backing_dev_info *bdi = wb->bdi; struct wb_writeback_work *work; long wrote = 0; set_bit(WB_writeback_running, &wb->state); - while ((work = get_next_work_item(bdi)) != NULL) { + while ((work = get_next_work_item(wb)) != NULL) { - trace_writeback_exec(bdi, work); + trace_writeback_exec(wb->bdi, work); wrote += wb_writeback(wb, work); @@ -1087,43 +1084,42 @@ static long wb_do_writeback(struct bdi_writeback *wb) * Handle writeback of dirty data for the device backed by this bdi. Also * reschedules periodically and does kupdated style flushing. */ -void bdi_writeback_workfn(struct work_struct *work) +void wb_workfn(struct work_struct *work) { struct bdi_writeback *wb = container_of(to_delayed_work(work), struct bdi_writeback, dwork); - struct backing_dev_info *bdi = wb->bdi; long pages_written; - set_worker_desc("flush-%s", dev_name(bdi->dev)); + set_worker_desc("flush-%s", dev_name(wb->bdi->dev)); current->flags |= PF_SWAPWRITE; if (likely(!current_is_workqueue_rescuer() || !test_bit(WB_registered, &wb->state))) { /* - * The normal path. Keep writing back @bdi until its + * The normal path. Keep writing back @wb until its * work_list is empty. Note that this path is also taken - * if @bdi is shutting down even when we're running off the + * if @wb is shutting down even when we're running off the * rescuer as work_list needs to be drained. */ do { pages_written = wb_do_writeback(wb); trace_writeback_pages_written(pages_written); - } while (!list_empty(&bdi->work_list)); + } while (!list_empty(&wb->work_list)); } else { /* * bdi_wq can't get enough workers and we're running off * the emergency worker. Don't hog it. Hopefully, 1024 is * enough for efficient IO. */ - pages_written = writeback_inodes_wb(&bdi->wb, 1024, + pages_written = writeback_inodes_wb(wb, 1024, WB_REASON_FORKER_THREAD); trace_writeback_pages_written(pages_written); } - if (!list_empty(&bdi->work_list)) + if (!list_empty(&wb->work_list)) mod_delayed_work(bdi_wq, &wb->dwork, 0); else if (wb_has_dirty_io(wb) && dirty_writeback_interval) - bdi_wakeup_thread_delayed(bdi); + wb_wakeup_delayed(wb); current->flags &= ~PF_SWAPWRITE; } @@ -1143,7 +1139,7 @@ void wakeup_flusher_threads(long nr_pages, enum wb_reason reason) list_for_each_entry_rcu(bdi, &bdi_list, bdi_list) { if (!bdi_has_dirty_io(bdi)) continue; - __bdi_start_writeback(bdi, nr_pages, false, reason); + __wb_start_writeback(&bdi->wb, nr_pages, false, reason); } rcu_read_unlock(); } @@ -1174,7 +1170,7 @@ static void wakeup_dirtytime_writeback(struct work_struct *w) list_for_each_entry_rcu(bdi, &bdi_list, bdi_list) { if (list_empty(&bdi->wb.b_dirty_time)) continue; - bdi_wakeup_thread(bdi); + wb_wakeup(&bdi->wb); } rcu_read_unlock(); schedule_delayed_work(&dirtytime_work, dirtytime_expire_interval * HZ); @@ -1347,7 +1343,7 @@ void __mark_inode_dirty(struct inode *inode, int flags) trace_writeback_dirty_inode_enqueue(inode); if (wakeup_bdi) - bdi_wakeup_thread_delayed(bdi); + wb_wakeup_delayed(&bdi->wb); return; } } @@ -1437,7 +1433,7 @@ void writeback_inodes_sb_nr(struct super_block *sb, if (sb->s_bdi == &noop_backing_dev_info) return; WARN_ON(!rwsem_is_locked(&sb->s_umount)); - bdi_queue_work(sb->s_bdi, &work); + wb_queue_work(&sb->s_bdi->wb, &work); wait_for_completion(&done); } EXPORT_SYMBOL(writeback_inodes_sb_nr); @@ -1521,7 +1517,7 @@ void sync_inodes_sb(struct super_block *sb) return; WARN_ON(!rwsem_is_locked(&sb->s_umount)); - bdi_queue_work(sb->s_bdi, &work); + wb_queue_work(&sb->s_bdi->wb, &work); wait_for_completion(&done); wait_sb_inodes(sb); -- cgit v1.2.3-55-g7522