tree 357690d6017682a4a21824f7d3f34a83406a136d
parent affee4b294a0fc97d67c8a77dc080c4dd262a79e
author Tejun Heo <tj@kernel.org> 1277798832 +0200
committer Tejun Heo <tj@kernel.org> 1277798832 +0200

workqueue: implement per-cwq active work limit

Add cwq->nr_active, cwq->max_active and cwq->delayed_work.  nr_active
counts the number of active works per cwq.  A work is active if it's
flushable (colored) and is on cwq's worklist.  If nr_active reaches
max_active, new works are queued on cwq->delayed_work and activated
later as works on the cwq complete and decrement nr_active.

cwq->max_active can be specified via the new @max_active parameter to
__create_workqueue() and is set to 1 for all workqueues for now.  As
each cwq has only single worker now, this double queueing doesn't
cause any behavior difference visible to its users.

This will be used to reimplement freeze/thaw and implement shared
worker pool.

Signed-off-by: Tejun Heo <tj@kernel.org>