On Mon, 2008-09-01 at 14:51 +0200, Nick Piggin wrote: > Hi, > > This is a sweep of the tree to remove volatile qualifier from bitops, and I > have then tried to fix the resulting fallout. This will be split up as > individual patches before submission, but for now I include the entire thing > in one. > > The benefit of this is to relieve the compiler of the constraints demanded > by volatile, we get a smaller icache footprint, generally due to fewer loads > and stores. It saves over 20k of text on an allyesconfig on x86-64. (BTW. gcc > really does some idiotic things when inline is nooped: it out of lines things > like constant_test_bit...) > > The downside is that we can no longer use bitops on volatile data types, but > there are very few users of this, and it would be nice to convert them away > from volatile anyway. I have attempted to do that here:
> drm: Made wrapped and context_state non volatile. Remember set_bit and > clear_bit can't be used to open and close a critical section (is > wrapped OK here?). Our ioctls rely on a lock being held around all the code, which is guaranteed by using .ioctl instead of .unlocked_ioctl as I understand. Removing the volatile from both of these should be safe. -- Eric Anholt [EMAIL PROTECTED] [EMAIL PROTECTED]
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