Re: bit fields && data tearing

Peter Hurley
2014-09-05T19:24:35Z

On 09/05/2014 03:05 PM, Paul E. McKenney wrote:
> On Fri, Sep 05, 2014 at 02:50:31PM -0400, Peter Hurley wrote:
>> On 09/05/2014 02:09 PM, Paul E. McKenney wrote:

[cut]

>>> ------------------------------------------------------------------------
>>>
>>> documentation: Record limitations of bitfields and small variables
>>>
>>> This commit documents the fact that it is not safe to use bitfields as
>>> shared variables in synchronization algorithms. It also documents that
>>> CPUs must provide one-byte and two-byte load and store instructions
>> ^
>> atomic
>
> Here you meant non-atomic? My guess is that you are referring to the
> fact that you could emulate a one-byte store on pre-EV56 Alpha CPUs
> using the ll and sc atomic-read-modify-write instructions, correct?

Yes, that's what I meant. I must be tired and am misreading the commit
message, or misinterpreting it's meaning.