Re: [PATCH 0/24] make atomic_read() behave consistently across allarchitectures
From: Chris Snook
Date: Thu Aug 16 2007 - 22:05:51 EST
Herbert Xu wrote:
On Thu, Aug 16, 2007 at 03:48:54PM -0400, Chris Snook wrote:
Can you find an actual atomic_read code snippet there that is
broken without the volatile modifier?
A whole bunch of atomic_read uses will be broken without the volatile
modifier once we start removing barriers that aren't needed if volatile
behavior is guaranteed.
Could you please cite the file/function names so we can
see whether removing the barrier makes sense?
Thanks,
At a glance, several architectures' implementations of smp_call_function() have
one or more legitimate atomic_read() busy-waits that shouldn't be using
CPU-relax. Some of them do work in the loop.
I'm sure there are plenty more examples that various maintainers could find in
their own code.
-- Chris
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