Message-ID: <40921.64.62.206.10.1214006079.squirrel@ruckus.brouhaha.com>
Date: Fri, 20 Jun 2008 16:54:39 -0700 (PDT)
Subject: Any lightweight way for one thread to force another thread to 
     suspend execution?
From: "Eric Smith" <eric@brouhaha.com>
To: linux-kernel@vger.kernel.org
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Is there any method for one thread to force another thread to suspend
execution, then later let it resume, that is lighter weight than using
signals?  I don't need it to be portable to anything other than Linux.
The suspend needs to be synchronous, but resume doesn't.

What I've thought about so far (but haven't tested) for thread A
to suspend thread B is to use a signal and two pthread conditions:

    Thread A                   Thread B
    -----------------------    -----------------------
    send signal to B

    wait on a cond 1

                               enter signal handler

                               signal cond 1

                               wait on cond 2

    wake up
    do stuff that needs
    thread B suspended

    signal cond 2

    continue                   wake up


Thanks for any suggestions!
Eric Smith

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