From: Andy Lutomirski <luto@mit.edu>
To: David Nicol <davidnicol@gmail.com>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: Is there a primitive to atomically release a spinlock and go to sleep?
Date: Wed, 01 Sep 2010 22:16:13 -0400 [thread overview]
Message-ID: <4C7F08ED.9010901@mit.edu> (raw)
In-Reply-To: <AANLkTimZnUEM6FFbgw==K3w6hURAgsAO8uRh5W1v6f_j@mail.gmail.com>
David Nicol wrote:
> I'm trying to do something involving multiple kthreads in an ioctl
> handler, and I want to avoid the
> race condition between the third and fourth steps of
>
> acquire mutex
> add &self to a list of threads which will get awakened by
> something else that is also aware of this list
> release mutex
> go to sleep
>
> Is there a standard atomic go-to-sleep function that takes as a
> parameter a pointer to spinlock to release after its state is set to
> TASK_INTERRUPTIBLE?
That wouldn't be enough -- the other thread could try to wake you up before you're even in the list of threads.
Look at wait_event_*() or read this:
http://book.chinaunix.net/special/ebook/PrenticeHall/PrenticeHallPTRTheLinuxKernelPrimer/0131181637/ch03lev1sec7.html
--Andy
prev parent reply other threads:[~2010-09-02 2:16 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-02 1:04 Is there a primitive to atomically release a spinlock and go to sleep? David Nicol
2010-09-02 2:16 ` Andy Lutomirski [this message]
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