Re: Why Semaphore Hardware-Dependent?

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Sun, 27 Aug 2006, Chris Wedgwood wrote:

> On Mon, Aug 28, 2006 at 10:18:35AM +1000, Paul Mackerras wrote:
> 
> > I believe the reason for not doing something like this on x86 was
> > the fact that we still support i386 processors, which don't have the
> > cmpxchg instruction.  That's fair enough, but I would be opposed to
> > making semaphores bigger and slower on PowerPC because of that.
> > Hence the two different styles of implementation.
> 
> The i386 is older than some of the kernel hackers, and given that a
> modern kernel is pretty painful with less than say 16MB or RAM in
> practice, I don't see that it would be all that terrible to drop
> support for ancient CPUs at some point (yes, I know some newer
> embedded (and similar) CPUs might be affected here too, but surely not
> that many that people really use --- and they could just use 2.4.x).

Also note that i386 has a cmpxchg emulation for those machines that do not 
support cmpxchg.

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]
  Powered by Linux