From: Kevin Diggs <kevdig@hypersurf•com>
To: linuxppc-dev@ozlabs•org
Subject: to schedule() or not to schedule() ?
Date: Sun, 03 Aug 2008 11:33:15 -0700 [thread overview]
Message-ID: <4895F9EB.8050508@hypersurf.com> (raw)
Hi,
I have the following near the top of my cpufreq driver target routine:
while(test_and_set_bit(cf750gxmCfgChangeBit,&cf750gxvStateBits)) {
/*
* Someone mucking with our cfg? (I hope it is ok to call
* schedule() here! - truth is I have no idea what I am doing
* ... my reasoning is I want to yeild the cpu so whoever is
* mucking around can finish)
*/
schedule();
}
This is to prevent bad things from happening if someone is trying to
change a parameter for the driver via sysfs while the target routine is
running. Fortunately, because I had a bug where this bit was not getting
cleared on one of the paths through the target routine ... I now know it
is not safe to call schedule (it got stuck in there - knocked out my adb
keyboard! - (I think target is called from a timer that the governor
sets up ... interrupt context?)).
How does one very briefly yield the cpu in this context?
kevin
next reply other threads:[~2008-08-03 18:45 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-08-03 18:33 Kevin Diggs [this message]
2008-08-05 18:37 ` to schedule() or not to schedule() ? Chris Friesen
2008-08-05 19:26 ` Kevin Diggs
2008-08-05 23:00 ` Michael Ellerman
2008-08-06 1:59 ` Kevin Diggs
2008-08-06 21:12 ` Arnd Bergmann
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