bdi, &bdi_debug_stats_fops);
if (!bdi->debug_stats) {
debugfs_remove(bdi->debug_dir);
+ bdi->debug_dir = NULL;
return -ENOMEM;
}
spin_lock_bh(&wb->work_lock);
if (!test_and_clear_bit(WB_registered, &wb->state)) {
spin_unlock_bh(&wb->work_lock);
- /*
- * Wait for wb shutdown to finish if someone else is just
- * running wb_shutdown(). Otherwise we could proceed to wb /
- * bdi destruction before wb_shutdown() is finished.
- */
- wait_on_bit(&wb->state, WB_shutting_down, TASK_UNINTERRUPTIBLE);
return;
}
- set_bit(WB_shutting_down, &wb->state);
spin_unlock_bh(&wb->work_lock);
cgwb_remove_from_bdi_list(wb);
mod_delayed_work(bdi_wq, &wb->dwork, 0);
flush_delayed_work(&wb->dwork);
WARN_ON(!list_empty(&wb->work_list));
- /*
- * Make sure bit gets cleared after shutdown is finished. Matches with
- * the barrier provided by test_and_clear_bit() above.
- */
- smp_wmb();
- clear_bit(WB_shutting_down, &wb->state);
}
static void wb_exit(struct bdi_writeback *wb)
* protected.
*/
static DEFINE_SPINLOCK(cgwb_lock);
+static struct workqueue_struct *cgwb_release_wq;
/**
* wb_congested_get_create - get or create a wb_congested
struct bdi_writeback *wb = container_of(work, struct bdi_writeback,
release_work);
+ mutex_lock(&wb->bdi->cgwb_release_mutex);
wb_shutdown(wb);
css_put(wb->memcg_css);
css_put(wb->blkcg_css);
+ mutex_unlock(&wb->bdi->cgwb_release_mutex);
fprop_local_destroy_percpu(&wb->memcg_completions);
percpu_ref_exit(&wb->refcnt);
{
struct bdi_writeback *wb = container_of(refcnt, struct bdi_writeback,
refcnt);
- schedule_work(&wb->release_work);
+ queue_work(cgwb_release_wq, &wb->release_work);
}
static void cgwb_kill(struct bdi_writeback *wb)
INIT_RADIX_TREE(&bdi->cgwb_tree, GFP_ATOMIC);
bdi->cgwb_congested_tree = RB_ROOT;
+ mutex_init(&bdi->cgwb_release_mutex);
+ init_rwsem(&bdi->wb_switch_rwsem);
ret = wb_init(&bdi->wb, bdi, 1, GFP_KERNEL);
if (!ret) {
spin_lock_irq(&cgwb_lock);
radix_tree_for_each_slot(slot, &bdi->cgwb_tree, &iter, 0)
cgwb_kill(*slot);
+ spin_unlock_irq(&cgwb_lock);
+ mutex_lock(&bdi->cgwb_release_mutex);
+ spin_lock_irq(&cgwb_lock);
while (!list_empty(&bdi->wb_list)) {
wb = list_first_entry(&bdi->wb_list, struct bdi_writeback,
bdi_node);
spin_lock_irq(&cgwb_lock);
}
spin_unlock_irq(&cgwb_lock);
+ mutex_unlock(&bdi->cgwb_release_mutex);
}
/**
spin_unlock_irq(&cgwb_lock);
}
+static int __init cgwb_init(void)
+{
+ /*
+ * There can be many concurrent release work items overwhelming
+ * system_wq. Put them in a separate wq and limit concurrency.
+ * There's no point in executing many of these in parallel.
+ */
+ cgwb_release_wq = alloc_workqueue("cgwb_release", 0, 1);
+ if (!cgwb_release_wq)
+ return -ENOMEM;
+
+ return 0;
+}
+subsys_initcall(cgwb_init);
+
#else /* CONFIG_CGROUP_WRITEBACK */
static int cgwb_bdi_init(struct backing_dev_info *bdi)