diff options
| author | Tejun Heo <tj@kernel.org> | 2012-03-05 13:15:19 -0800 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2012-03-06 21:27:23 +0100 |
| commit | 03aa264ac15637b6f98374270bcdf31400965505 (patch) | |
| tree | 6fa9ca54d3f775fba19123790f6655158034a1d8 /block/elevator.c | |
| parent | 4eef3049986e8397d5003916aed8cad6567a5e02 (diff) | |
blkcg: let blkcg core manage per-queue blkg list and counter
With the previous patch to move blkg list heads and counters to
request_queue and blkg, logic to manage them in both policies are
almost identical and can be moved to blkcg core.
This patch moves blkg link logic into blkg_lookup_create(), implements
common blkg unlink code in blkg_destroy(), and updates
blkg_destory_all() so that it's policy specific and can skip root
group. The updated blkg_destroy_all() is now used to both clear queue
for bypassing and elv switching, and release all blkgs on q exit.
This patch introduces a race window where policy [de]registration may
race against queue blkg clearing. This can only be a problem on cfq
unload and shouldn't be a real problem in practice (and we have many
other places where this race already exists). Future patches will
remove these unlikely races.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/elevator.c')
| -rw-r--r-- | block/elevator.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/block/elevator.c b/block/elevator.c index 8c7561fd2c79..d4d39dab841a 100644 --- a/block/elevator.c +++ b/block/elevator.c @@ -876,7 +876,7 @@ static int elevator_switch(struct request_queue *q, struct elevator_type *new_e) { struct elevator_queue *old = q->elevator; bool registered = old->registered; - int err; + int i, err; /* * Turn on BYPASS and drain all requests w/ elevator private data. @@ -895,7 +895,8 @@ static int elevator_switch(struct request_queue *q, struct elevator_type *new_e) ioc_clear_queue(q); spin_unlock_irq(q->queue_lock); - blkg_destroy_all(q); + for (i = 0; i < BLKIO_NR_POLICIES; i++) + blkg_destroy_all(q, i, false); /* allocate, init and register new elevator */ err = -ENOMEM; |