blk-throttle: add throtl_grp->service_queue
Currently, there's single service_queue per queue -
throtl_data->service_queue. All active throtl_grp's are queued on the
queue and dispatched according to their limits. To support hierarchy,
this will be expanded such that active throtl_grp's form a tree
anchored at throtl_data->service_queue and chained through each
intermediate throtl_grp's service_queue.
This patch adds throtl_grp->service_queue to prepare for hierarchy
support. The initialization function - throtl_service_queue_init() -
is added and replaces the macro initializer. The newly added
tg->service_queue isn't used yet. Following patches will do.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index ebaaaa9..7340440 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -33,9 +33,6 @@
unsigned long first_pending_disptime; /* disptime of the first tg */
};
-#define THROTL_SERVICE_QUEUE_INITIALIZER \
- (struct throtl_service_queue){ .pending_tree = RB_ROOT }
-
enum tg_state_flags {
THROTL_TG_PENDING = 1 << 0, /* on parent's pending tree */
};
@@ -60,6 +57,9 @@
/* throtl_data this group belongs to */
struct throtl_data *td;
+ /* this group's service queue */
+ struct throtl_service_queue service_queue;
+
/*
* Dispatch time in jiffies. This is the estimated time when group
* will unthrottle and is ready to dispatch more bio. It is used as
@@ -190,11 +190,18 @@
goto alloc_stats;
}
+/* init a service_queue, assumes the caller zeroed it */
+static void throtl_service_queue_init(struct throtl_service_queue *sq)
+{
+ sq->pending_tree = RB_ROOT;
+}
+
static void throtl_pd_init(struct blkcg_gq *blkg)
{
struct throtl_grp *tg = blkg_to_tg(blkg);
unsigned long flags;
+ throtl_service_queue_init(&tg->service_queue);
RB_CLEAR_NODE(&tg->rb_node);
tg->td = blkg->q->td;
bio_list_init(&tg->bio_lists[0]);
@@ -1168,8 +1175,8 @@
if (!td)
return -ENOMEM;
- td->service_queue = THROTL_SERVICE_QUEUE_INITIALIZER;
INIT_DELAYED_WORK(&td->dispatch_work, blk_throtl_dispatch_work_fn);
+ throtl_service_queue_init(&td->service_queue);
q->td = td;
td->queue = q;