From: Tejun Heo <tj@kernel.org>
Date: Tue, 29 Jun 2010 08:07:12 +0000 (+0200)
Subject: workqueue: reimplement workqueue freeze using max_active
X-Git-Tag: v2.6.36-rc1~506^2~38
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a0a1a5fd4fb15ec61117c759fe9f5c16c53d9e9c;p=pandora-kernel.git

workqueue: reimplement workqueue freeze using max_active

Currently, workqueue freezing is implemented by marking the worker
freezeable and calling try_to_freeze() from dispatch loop.
Reimplement it using cwq->limit so that the workqueue is frozen
instead of the worker.

* workqueue_struct->saved_max_active is added which stores the
  specified max_active on initialization.

* On freeze, all cwq->max_active's are quenched to zero.  Freezing is
  complete when nr_active on all cwqs reach zero.

* On thaw, all cwq->max_active's are restored to wq->saved_max_active
  and the worklist is repopulated.

This new implementation allows having single shared pool of workers
per cpu.

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

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