Re: bitops atomicity question
Darren Reed (darrenr@cyber.com.au)
Mon, 25 Aug 1997 17:54:27 +1000 (EST)
In some mail I received from David S. Miller, sie wrote
>
> Date: Sun, 24 Aug 1997 23:55:21 +0200
> From: Pavel Machek <pavel@Elf.mj.gts.cz>
>
> I just would like to ask:
>
> Is test_and_clear_bit guaranteed to be atomic on SMP machines? (I
> would like to create my own locking from userland - ipc semaphores
> are way too slow - and need some atomic operations...)
>
> Depends upon the platform:
>
> Intel: If 'lock' prefix is there, yes.
> Alpha: yes
> Sparc32: no
> Sparc64: yes
> PPC: yes (??? Cort, correct me if I'm wrong)
> m68k: N/A yet 8-)
hmmm, what happened to the CAS/TAS (and firends) on the m68k ? get dropped
from the '30 or is SMP yet to be ported o m68k anyway ?