Exemplo n.º 1
0
static void cgwb_bdi_destroy(struct backing_dev_info *bdi)
{
	struct radix_tree_iter iter;
	struct rb_node *rbn;
	void **slot;

	WARN_ON(test_bit(WB_registered, &bdi->wb.state));

	spin_lock_irq(&cgwb_lock);

	radix_tree_for_each_slot(slot, &bdi->cgwb_tree, &iter, 0)
		cgwb_kill(*slot);

	while ((rbn = rb_first(&bdi->cgwb_congested_tree))) {
		struct bdi_writeback_congested *congested =
			rb_entry(rbn, struct bdi_writeback_congested, rb_node);

		rb_erase(rbn, &bdi->cgwb_congested_tree);
		congested->bdi = NULL;	/* mark @congested unlinked */
	}

	spin_unlock_irq(&cgwb_lock);

	/*
	 * All cgwb's and their congested states must be shutdown and
	 * released before returning.  Drain the usage counter to wait for
	 * all cgwb's and cgwb_congested's ever created on @bdi.
	 */
	atomic_dec(&bdi->usage_cnt);
	wait_event(cgwb_release_wait, !atomic_read(&bdi->usage_cnt));
}
Exemplo n.º 2
0
/**
 * wb_blkcg_offline - kill all wb's associated with a blkcg being offlined
 * @blkcg: blkcg being offlined
 *
 * Also prevents creation of any new wb's associated with @blkcg.
 */
void wb_blkcg_offline(struct blkcg *blkcg)
{
	struct bdi_writeback *wb, *next;

	spin_lock_irq(&cgwb_lock);
	list_for_each_entry_safe(wb, next, &blkcg->cgwb_list, blkcg_node)
		cgwb_kill(wb);
	blkcg->cgwb_list.next = NULL;	/* prevent new wb's */
	spin_unlock_irq(&cgwb_lock);
}
Exemplo n.º 3
0
/**
 * wb_memcg_offline - kill all wb's associated with a memcg being offlined
 * @memcg: memcg being offlined
 *
 * Also prevents creation of any new wb's associated with @memcg.
 */
void wb_memcg_offline(struct mem_cgroup *memcg)
{
	struct list_head *memcg_cgwb_list = mem_cgroup_cgwb_list(memcg);
	struct bdi_writeback *wb, *next;

	spin_lock_irq(&cgwb_lock);
	list_for_each_entry_safe(wb, next, memcg_cgwb_list, memcg_node)
		cgwb_kill(wb);
	memcg_cgwb_list->next = NULL;	/* prevent new wb's */
	spin_unlock_irq(&cgwb_lock);
}
Exemplo n.º 4
0
static void cgwb_bdi_unregister(struct backing_dev_info *bdi)
{
	struct radix_tree_iter iter;
	void **slot;
	struct bdi_writeback *wb;

	WARN_ON(test_bit(WB_registered, &bdi->wb.state));

	spin_lock_irq(&cgwb_lock);
	radix_tree_for_each_slot(slot, &bdi->cgwb_tree, &iter, 0)
		cgwb_kill(*slot);

	while (!list_empty(&bdi->wb_list)) {
		wb = list_first_entry(&bdi->wb_list, struct bdi_writeback,
				      bdi_node);
		spin_unlock_irq(&cgwb_lock);
		wb_shutdown(wb);
		spin_lock_irq(&cgwb_lock);
	}
	spin_unlock_irq(&cgwb_lock);
}
Exemplo n.º 5
0
static int cgwb_create(struct backing_dev_info *bdi,
		       struct cgroup_subsys_state *memcg_css, gfp_t gfp)
{
	struct mem_cgroup *memcg;
	struct cgroup_subsys_state *blkcg_css;
	struct blkcg *blkcg;
	struct list_head *memcg_cgwb_list, *blkcg_cgwb_list;
	struct bdi_writeback *wb;
	unsigned long flags;
	int ret = 0;

	memcg = mem_cgroup_from_css(memcg_css);
	blkcg_css = cgroup_get_e_css(memcg_css->cgroup, &io_cgrp_subsys);
	blkcg = css_to_blkcg(blkcg_css);
	memcg_cgwb_list = mem_cgroup_cgwb_list(memcg);
	blkcg_cgwb_list = &blkcg->cgwb_list;

	/* look up again under lock and discard on blkcg mismatch */
	spin_lock_irqsave(&cgwb_lock, flags);
	wb = radix_tree_lookup(&bdi->cgwb_tree, memcg_css->id);
	if (wb && wb->blkcg_css != blkcg_css) {
		cgwb_kill(wb);
		wb = NULL;
	}
	spin_unlock_irqrestore(&cgwb_lock, flags);
	if (wb)
		goto out_put;

	/* need to create a new one */
	wb = kmalloc(sizeof(*wb), gfp);
	if (!wb)
		return -ENOMEM;

	ret = wb_init(wb, bdi, blkcg_css->id, gfp);
	if (ret)
		goto err_free;

	ret = percpu_ref_init(&wb->refcnt, cgwb_release, 0, gfp);
	if (ret)
		goto err_wb_exit;

	ret = fprop_local_init_percpu(&wb->memcg_completions, gfp);
	if (ret)
		goto err_ref_exit;

	wb->memcg_css = memcg_css;
	wb->blkcg_css = blkcg_css;
	INIT_WORK(&wb->release_work, cgwb_release_workfn);
	set_bit(WB_registered, &wb->state);

	/*
	 * The root wb determines the registered state of the whole bdi and
	 * memcg_cgwb_list and blkcg_cgwb_list's next pointers indicate
	 * whether they're still online.  Don't link @wb if any is dead.
	 * See wb_memcg_offline() and wb_blkcg_offline().
	 */
	ret = -ENODEV;
	spin_lock_irqsave(&cgwb_lock, flags);
	if (test_bit(WB_registered, &bdi->wb.state) &&
	    blkcg_cgwb_list->next && memcg_cgwb_list->next) {
		/* we might have raced another instance of this function */
		ret = radix_tree_insert(&bdi->cgwb_tree, memcg_css->id, wb);
		if (!ret) {
			atomic_inc(&bdi->usage_cnt);
			list_add_tail_rcu(&wb->bdi_node, &bdi->wb_list);
			list_add(&wb->memcg_node, memcg_cgwb_list);
			list_add(&wb->blkcg_node, blkcg_cgwb_list);
			css_get(memcg_css);
			css_get(blkcg_css);
		}
	}
	spin_unlock_irqrestore(&cgwb_lock, flags);
	if (ret) {
		if (ret == -EEXIST)
			ret = 0;
		goto err_fprop_exit;
	}
	goto out_put;

err_fprop_exit:
	fprop_local_destroy_percpu(&wb->memcg_completions);
err_ref_exit:
	percpu_ref_exit(&wb->refcnt);
err_wb_exit:
	wb_exit(wb);
err_free:
	kfree(wb);
out_put:
	css_put(blkcg_css);
	return ret;
}