Messages in this thread | | | Date | Sun, 11 Oct 2009 12:26:32 -0700 | From | Arjan van de Ven <> | Subject | Re: [PATCH] sound_core.c: Remove BKL from soundcore_open |
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On Sun, 11 Oct 2009 20:17:59 +0100 Alan Cox <alan@lxorguk.ukuu.org.uk> wrote:
> > it's getting time though to bite the bullet and make it a real > > normal mutex. Lockdep will then flag a bunch of sh*t we'll need to > > fix, but without doing that we're never going to really make > > progress. > > It won't. Instead you get situations like one ioctl blocking another > to an unrelated device that just causes weird failures and performance > problems, or in some cases deadlocks.
yes the bkl using code will be slower because it'll now hit contention.
The deadlocks we need to catch imo; those are the behaviors that are the worst offenders in terms of BKL weird behavior.
> > Open routines block so it takes about 5 seconds of thought to realise > that using a mutex here is brain dead and doesn't work.
it also takes 5 seconds to realize "uh oh. they block. BKL is rather limited in what it provides".
-- Arjan van de Ven Intel Open Source Technology Centre For development, discussion and tips for power savings, visit http://www.lesswatts.org
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