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From: "Rafael J. Wysocki" <rjw@sisk.pl>
To: Tejun Heo <tj@kernel.org>
Subject: Re: [PATCH 2/2] firmware_class: Move request_firmware_nowait() to workqueues
Date: Wed, 28 Mar 2012 00:21:27 +0200
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Cc: Stephen Boyd <sboyd@codeaurora.org>, linux-kernel@vger.kernel.org,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Saravana Kannan <skannan@codeaurora.org>,
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        "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>,
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On Wednesday, March 28, 2012, Tejun Heo wrote:
> On Tue, Mar 27, 2012 at 02:28:30PM -0700, Stephen Boyd wrote:
> > Oddly enough a work_struct was already part of the firmware_work
> > structure but nobody was using it. Instead of creating a new
> > kthread for each request_firmware_nowait() call just schedule the
> > work on the long system workqueue. This should avoid some overhead
> > in forking new threads when they're not strictly necessary.
> > 
> > Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
> > ---
> > 
> > Is it better to use alloc_workqueue() and not put these on the system
> > long workqueue?
> 
> No, just use schedule_work() unless there are specific requirements
> which can't be fulfilled that way (e.g. it's on memory allocation
> path, may consume large amount of cpu cycles, ...)

It may wait quite long.

Rafael