Messages in this thread | | | Date | Thu, 23 Oct 2003 10:09:42 -0700 | From | Tim Hockin <> | Subject | Re: [NFS] RE: [autofs] multiple servers per automount |
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On Thu, Oct 23, 2003 at 01:00:57PM -0400, Mike Waychison wrote: > >Would a GFP_ATOMIC make a difference to the analysis?
> Yes, sleeping within a spinlock is bad practice because it may > eventually deadlock. Pretend that the lock is taken, the call to > kmalloc is made, the mm system doesn't have any immidiately free memory > and through some flow of execution requires that a some pseudo-block > device backed filesystem needs to be mounted -> deadlock. I have no > idea if this is currently a likely scenario, however not sleeping within > a lock is 'The Right Thing' and should be avoided at all costs.
it's worse than that. It's forbidden. It's a VERY likely deadlock scenario in the general sense, even if this particular case is not. If you need to lock something and you need to sleep holding that lock, use a semaphore.
-- Notice that as computers are becoming easier and easier to use, suddenly there's a big market for "Dummies" books. Cause and effect, or merely an ironic juxtaposition of unrelated facts?
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