From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755397Ab2BVBrx (ORCPT ); Tue, 21 Feb 2012 20:47:53 -0500 Received: from mail-pz0-f46.google.com ([209.85.210.46]:45648 "EHLO mail-pz0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755271Ab2BVBrt (ORCPT ); Tue, 21 Feb 2012 20:47:49 -0500 Authentication-Results: mr.google.com; spf=pass (google.com: domain of htejun@gmail.com designates 10.68.233.36 as permitted sender) smtp.mail=htejun@gmail.com; dkim=pass header.i=htejun@gmail.com From: Tejun Heo To: axboe@kernel.dk, vgoyal@redhat.com Cc: ctalbott@google.com, rni@google.com, linux-kernel@vger.kernel.org, Tejun Heo Subject: [PATCH 20/36] blkcg: clear all request_queues on blkcg policy [un]registrations Date: Tue, 21 Feb 2012 17:46:47 -0800 Message-Id: <1329875223-5102-21-git-send-email-tj@kernel.org> X-Mailer: git-send-email 1.7.7.3 In-Reply-To: <1329875223-5102-1-git-send-email-tj@kernel.org> References: <1329875223-5102-1-git-send-email-tj@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Keep track of all request_queues which have blkcg initialized and turn on bypass and invoke blkcg_clear_queue() on all before making changes to blkcg policies. This is to prepare for moving blkg management into blkcg core. Note that this uses more brute force than necessary. Finer grained shoot down will be implemented later and given that policy [un]registration almost never happens on running systems (blk-throtl can't be built as a module and cfq usually is the builtin default iosched), this shouldn't be a problem for the time being. Signed-off-by: Tejun Heo Cc: Vivek Goyal --- block/blk-cgroup.c | 48 +++++++++++++++++++++++++++++++++++++++++++++++- include/linux/blkdev.h | 3 +++ 2 files changed, 50 insertions(+), 1 deletions(-) diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index eadc21c..1695856 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -27,6 +27,9 @@ static DEFINE_SPINLOCK(blkio_list_lock); static LIST_HEAD(blkio_list); +static DEFINE_MUTEX(all_q_mutex); +static LIST_HEAD(all_q_list); + struct blkio_cgroup blkio_root_cgroup = { .weight = 2*BLKIO_WEIGHT_DEFAULT }; EXPORT_SYMBOL_GPL(blkio_root_cgroup); @@ -1461,9 +1464,20 @@ done: */ int blkcg_init_queue(struct request_queue *q) { + int ret; + might_sleep(); - return blk_throtl_init(q); + ret = blk_throtl_init(q); + if (ret) + return ret; + + mutex_lock(&all_q_mutex); + INIT_LIST_HEAD(&q->all_q_node); + list_add_tail(&q->all_q_node, &all_q_list); + mutex_unlock(&all_q_mutex); + + return 0; } /** @@ -1487,6 +1501,10 @@ void blkcg_drain_queue(struct request_queue *q) */ void blkcg_exit_queue(struct request_queue *q) { + mutex_lock(&all_q_mutex); + list_del_init(&q->all_q_node); + mutex_unlock(&all_q_mutex); + blk_throtl_exit(q); } @@ -1532,8 +1550,33 @@ static void blkiocg_attach(struct cgroup_subsys *ss, struct cgroup *cgrp, } } +static void blkcg_bypass_start(void) + __acquires(&all_q_mutex) +{ + struct request_queue *q; + + mutex_lock(&all_q_mutex); + + list_for_each_entry(q, &all_q_list, all_q_node) { + blk_queue_bypass_start(q); + blkg_destroy_all(q); + } +} + +static void blkcg_bypass_end(void) + __releases(&all_q_mutex) +{ + struct request_queue *q; + + list_for_each_entry(q, &all_q_list, all_q_node) + blk_queue_bypass_end(q); + + mutex_unlock(&all_q_mutex); +} + void blkio_policy_register(struct blkio_policy_type *blkiop) { + blkcg_bypass_start(); spin_lock(&blkio_list_lock); BUG_ON(blkio_policy[blkiop->plid]); @@ -1541,11 +1584,13 @@ void blkio_policy_register(struct blkio_policy_type *blkiop) list_add_tail(&blkiop->list, &blkio_list); spin_unlock(&blkio_list_lock); + blkcg_bypass_end(); } EXPORT_SYMBOL_GPL(blkio_policy_register); void blkio_policy_unregister(struct blkio_policy_type *blkiop) { + blkcg_bypass_start(); spin_lock(&blkio_list_lock); BUG_ON(blkio_policy[blkiop->plid] != blkiop); @@ -1553,5 +1598,6 @@ void blkio_policy_unregister(struct blkio_policy_type *blkiop) list_del_init(&blkiop->list); spin_unlock(&blkio_list_lock); + blkcg_bypass_end(); } EXPORT_SYMBOL_GPL(blkio_policy_unregister); diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 315db1d..e8c0bbd 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -397,6 +397,9 @@ struct request_queue { struct bsg_class_device bsg_dev; #endif +#ifdef CONFIG_BLK_CGROUP + struct list_head all_q_node; +#endif #ifdef CONFIG_BLK_DEV_THROTTLING /* Throttle data */ struct throtl_data *td; -- 1.7.7.3