diff options
| -rw-r--r-- | fs/fs-writeback.c | 116 |
1 files changed, 30 insertions, 86 deletions
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index c9def2115aca..38e103506484 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -53,8 +53,6 @@ struct wb_writeback_work { unsigned int for_background:1; unsigned int for_sync:1; /* sync(2) WB_SYNC_ALL writeback */ unsigned int auto_free:1; /* free on completion */ - unsigned int single_wait:1; - unsigned int single_done:1; enum wb_reason reason; /* why was writeback initiated? */ struct list_head list; /* pending work list */ @@ -181,11 +179,8 @@ static void wb_queue_work(struct bdi_writeback *wb, trace_writeback_queue(wb->bdi, work); spin_lock_bh(&wb->work_lock); - if (!test_bit(WB_registered, &wb->state)) { - if (work->single_wait) - work->single_done = 1; + if (!test_bit(WB_registered, &wb->state)) goto out_unlock; - } if (work->done) atomic_inc(&work->done->cnt); list_add_tail(&work->list, &wb->work_list); @@ -738,32 +733,6 @@ int inode_congested(struct inode *inode, int cong_bits) EXPORT_SYMBOL_GPL(inode_congested); /** - * wb_wait_for_single_work - wait for completion of a single bdi_writeback_work - * @bdi: bdi the work item was issued to - * @work: work item to wait for - * - * Wait for the completion of @work which was issued to one of @bdi's - * bdi_writeback's. The caller must have set @work->single_wait before - * issuing it. This wait operates independently fo - * wb_wait_for_completion() and also disables automatic freeing of @work. - */ -static void wb_wait_for_single_work(struct backing_dev_info *bdi, - struct wb_writeback_work *work) -{ - if (WARN_ON_ONCE(!work->single_wait)) - return; - - wait_event(bdi->wb_waitq, work->single_done); - - /* - * Paired with smp_wmb() in wb_do_writeback() and ensures that all - * modifications to @work prior to assertion of ->single_done is - * visible to the caller once this function returns. - */ - smp_rmb(); -} - -/** * wb_split_bdi_pages - split nr_pages to write according to bandwidth * @wb: target bdi_writeback to split @nr_pages to * @nr_pages: number of pages to write for the whole bdi @@ -792,38 +761,6 @@ static long wb_split_bdi_pages(struct bdi_writeback *wb, long nr_pages) } /** - * wb_clone_and_queue_work - clone a wb_writeback_work and issue it to a wb - * @wb: target bdi_writeback - * @base_work: source wb_writeback_work - * - * Try to make a clone of @base_work and issue it to @wb. If cloning - * succeeds, %true is returned; otherwise, @base_work is issued directly - * and %false is returned. In the latter case, the caller is required to - * wait for @base_work's completion using wb_wait_for_single_work(). - * - * A clone is auto-freed on completion. @base_work never is. - */ -static bool wb_clone_and_queue_work(struct bdi_writeback *wb, - struct wb_writeback_work *base_work) -{ - struct wb_writeback_work *work; - - work = kmalloc(sizeof(*work), GFP_ATOMIC); - if (work) { - *work = *base_work; - work->auto_free = 1; - work->single_wait = 0; - } else { - work = base_work; - work->auto_free = 0; - work->single_wait = 1; - } - work->single_done = 0; - wb_queue_work(wb, work); - return work != base_work; -} - -/** * bdi_split_work_to_wbs - split a wb_writeback_work to all wb's of a bdi * @bdi: target backing_dev_info * @base_work: wb_writeback_work to issue @@ -838,7 +775,6 @@ static void bdi_split_work_to_wbs(struct backing_dev_info *bdi, struct wb_writeback_work *base_work, bool skip_if_busy) { - long nr_pages = base_work->nr_pages; int next_memcg_id = 0; struct bdi_writeback *wb; struct wb_iter iter; @@ -850,17 +786,39 @@ static void bdi_split_work_to_wbs(struct backing_dev_info *bdi, restart: rcu_read_lock(); bdi_for_each_wb(wb, bdi, &iter, next_memcg_id) { + DEFINE_WB_COMPLETION_ONSTACK(fallback_work_done); + struct wb_writeback_work fallback_work; + struct wb_writeback_work *work; + long nr_pages; + if (!wb_has_dirty_io(wb) || (skip_if_busy && writeback_in_progress(wb))) continue; - base_work->nr_pages = wb_split_bdi_pages(wb, nr_pages); - if (!wb_clone_and_queue_work(wb, base_work)) { - next_memcg_id = wb->memcg_css->id + 1; - rcu_read_unlock(); - wb_wait_for_single_work(bdi, base_work); - goto restart; + nr_pages = wb_split_bdi_pages(wb, base_work->nr_pages); + + work = kmalloc(sizeof(*work), GFP_ATOMIC); + if (work) { + *work = *base_work; + work->nr_pages = nr_pages; + work->auto_free = 1; + wb_queue_work(wb, work); + continue; } + + /* alloc failed, execute synchronously using on-stack fallback */ + work = &fallback_work; + *work = *base_work; + work->nr_pages = nr_pages; + work->auto_free = 0; + work->done = &fallback_work_done; + + wb_queue_work(wb, work); + + next_memcg_id = wb->memcg_css->id + 1; + rcu_read_unlock(); + wb_wait_for_completion(bdi, &fallback_work_done); + goto restart; } rcu_read_unlock(); } @@ -902,8 +860,6 @@ static void bdi_split_work_to_wbs(struct backing_dev_info *bdi, if (bdi_has_dirty_io(bdi) && (!skip_if_busy || !writeback_in_progress(&bdi->wb))) { base_work->auto_free = 0; - base_work->single_wait = 0; - base_work->single_done = 0; wb_queue_work(&bdi->wb, base_work); } } @@ -1794,26 +1750,14 @@ static long wb_do_writeback(struct bdi_writeback *wb) set_bit(WB_writeback_running, &wb->state); while ((work = get_next_work_item(wb)) != NULL) { struct wb_completion *done = work->done; - bool need_wake_up = false; trace_writeback_exec(wb->bdi, work); wrote += wb_writeback(wb, work); - if (work->single_wait) { - WARN_ON_ONCE(work->auto_free); - /* paired w/ rmb in wb_wait_for_single_work() */ - smp_wmb(); - work->single_done = 1; - need_wake_up = true; - } else if (work->auto_free) { + if (work->auto_free) kfree(work); - } - if (done && atomic_dec_and_test(&done->cnt)) - need_wake_up = true; - - if (need_wake_up) wake_up_all(&wb->bdi->wb_waitq); } |