malloc and threads

Daniel Jacobowitz drow@mvista.com
Sun Dec 1 09:09:00 GMT 2002


On Wed, Nov 27, 2002 at 09:07:58AM -0800, David Boreham wrote:
> > XScale is an ARM based processor 
> 
> Perhaps there is a bug in the XScale locking code
> or in the CPU hardware ?

Well, there are bugs in the ARM locking code.  I recommend interested
parties look at the conversation between myself and Richard Earnshaw
about this on the gcc-patches list, on Oct. 4th-7th:
  Subject: Atomic operations on the ARM

I don't believe it will affect malloc's use of locks; in short
test-and-set works but exchange-and-add is not atomic.

I'm not sure if compare_and_swap works correctly or not.  A glance
suggests that it does not.

-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer



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