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From: Tejun Heo <tj@kernel.org>
To: axboe@kernel.dk, vgoyal@redhat.com
Cc: ctalbott@google.com, rni@google.com,
	linux-kernel@vger.kernel.org, Tejun Heo <tj@kernel.org>
Subject: [PATCH 11/16] blkcg: add blkio_policy[] array and allow one policy per policy ID
Date: Wed,  1 Feb 2012 12:50:24 -0800	[thread overview]
Message-ID: <1328129429-11823-12-git-send-email-tj@kernel.org> (raw)
In-Reply-To: <1328129429-11823-1-git-send-email-tj@kernel.org>

Block cgroup policies are maintained in a linked list and,
theoretically, multiple policies sharing the same policy ID are
allowed.

This patch temporarily restricts one policy per plid and adds
blkio_policy[] array which indexes registered policy types by plid.
Both the restriction and blkio_policy[] array are transitional and
will be removed once API cleanup is complete.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
---
 block/blk-cgroup.c |   10 ++++++++++
 block/blk-cgroup.h |    2 ++
 2 files changed, 12 insertions(+), 0 deletions(-)

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index cd9fbae..3c13943 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -29,6 +29,8 @@ static LIST_HEAD(blkio_list);
 struct blkio_cgroup blkio_root_cgroup = { .weight = 2*BLKIO_WEIGHT_DEFAULT };
 EXPORT_SYMBOL_GPL(blkio_root_cgroup);
 
+static struct blkio_policy_type *blkio_policy[BLKIO_NR_POLICIES];
+
 static struct cgroup_subsys_state *blkiocg_create(struct cgroup_subsys *,
 						  struct cgroup *);
 static int blkiocg_can_attach(struct cgroup_subsys *, struct cgroup *,
@@ -1694,7 +1696,11 @@ static void blkiocg_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
 void blkio_policy_register(struct blkio_policy_type *blkiop)
 {
 	spin_lock(&blkio_list_lock);
+
+	BUG_ON(blkio_policy[blkiop->plid]);
+	blkio_policy[blkiop->plid] = blkiop;
 	list_add_tail(&blkiop->list, &blkio_list);
+
 	spin_unlock(&blkio_list_lock);
 }
 EXPORT_SYMBOL_GPL(blkio_policy_register);
@@ -1702,7 +1708,11 @@ EXPORT_SYMBOL_GPL(blkio_policy_register);
 void blkio_policy_unregister(struct blkio_policy_type *blkiop)
 {
 	spin_lock(&blkio_list_lock);
+
+	BUG_ON(blkio_policy[blkiop->plid] != blkiop);
+	blkio_policy[blkiop->plid] = NULL;
 	list_del_init(&blkiop->list);
+
 	spin_unlock(&blkio_list_lock);
 }
 EXPORT_SYMBOL_GPL(blkio_policy_unregister);
diff --git a/block/blk-cgroup.h b/block/blk-cgroup.h
index 41c960b..562fa55 100644
--- a/block/blk-cgroup.h
+++ b/block/blk-cgroup.h
@@ -19,6 +19,8 @@
 enum blkio_policy_id {
 	BLKIO_POLICY_PROP = 0,		/* Proportional Bandwidth division */
 	BLKIO_POLICY_THROTL,		/* Throttling */
+
+	BLKIO_NR_POLICIES,
 };
 
 /* Max limits for throttle policy */
-- 
1.7.7.3


  parent reply	other threads:[~2012-02-01 20:51 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-02-01 20:50 [PATCHSET] blkcg: kill policy node and blkg->dev, take#4 Tejun Heo
2012-02-01 20:50 ` [PATCH 01/16] blkcg: make CONFIG_BLK_CGROUP bool Tejun Heo
2012-02-02  6:53   ` Li Zefan
2012-02-02 17:14     ` Tejun Heo
2012-02-01 20:50 ` [PATCH 02/16] cfq: don't register propio policy if !CONFIG_CFQ_GROUP_IOSCHED Tejun Heo
2012-02-01 20:50 ` [PATCH 03/16] elevator: clear auxiliary data earlier during elevator switch Tejun Heo
2012-02-01 20:50 ` [PATCH 04/16] elevator: make elevator_init_fn() return 0/-errno Tejun Heo
2012-02-01 20:50 ` [PATCH 05/16] block: implement blk_queue_bypass_start/end() Tejun Heo
2012-02-01 20:50 ` [PATCH 06/16] block: extend queue bypassing to cover blkcg policies Tejun Heo
2012-02-01 20:50 ` [PATCH 07/16] blkcg: shoot down blkio_groups on elevator switch Tejun Heo
2012-02-01 20:50 ` [PATCH 08/16] blkcg: move rcu_read_lock() outside of blkio_group get functions Tejun Heo
2012-02-01 20:50 ` [PATCH 09/16] blkcg: update blkg get functions take blkio_cgroup as parameter Tejun Heo
2012-02-01 20:50 ` [PATCH 10/16] blkcg: use q and plid instead of opaque void * for blkio_group association Tejun Heo
2012-02-01 20:50 ` Tejun Heo [this message]
2012-02-01 20:50 ` [PATCH 12/16] blkcg: use the usual get blkg path for root blkio_group Tejun Heo
2012-02-01 20:50 ` [PATCH 13/16] blkcg: factor out blkio_group creation Tejun Heo
2012-02-01 20:50 ` [PATCH 14/16] blkcg: don't allow or retain configuration of missing devices Tejun Heo
2012-02-01 20:50 ` [PATCH 15/16] blkcg: kill blkio_policy_node Tejun Heo
2012-02-01 20:50 ` [PATCH 16/16] blkcg: kill the mind-bending blkg->dev Tejun Heo
  -- strict thread matches above, loose matches on Subject: below --
2012-01-23 23:09 [PATCHSET] blkcg: kill policy node and blkg->dev, take#3 Tejun Heo
2012-01-23 23:09 ` [PATCH 11/16] blkcg: add blkio_policy[] array and allow one policy per policy ID Tejun Heo

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