Re: [cpuops cmpxchg double V2 1/4] Gen eric support for this_cpu_cmpxchg_double

[H. Peter Anvin]

Don't apply "packed" to a structure which needs padding!  That's just user error.

"Mathieu Desnoyers" <mathieu.desnoyers@xxxxxxxxxxxx> wrote:

>* Tejun Heo (tj@xxxxxxxxxx) wrote:
>[...]
>> > (note: packed here along with "aligned" does _not_ generate ugly
>> > bytewise read/write memory ops like "packed" alone. The use of
>> > "packed" is to let the compiler down-align the structure to the
>> > value requested, instead of uselessly aligning it on 32-byte if it
>> > chooses to.)
>> 
>> Yeah, good point.  :-)
>
>For the records, I just noticed that "packed, aligned(8)" can generate
>unaligned
>accesses on sparc64 by removing the padding between a "int" and a
>following
>pointer. So we should not use it.
>
>Thanks,
>
>Mathieu
>
>-- 
>Mathieu Desnoyers
>Operating System Efficiency R&D Consultant
>EfficiOS Inc.
>http://www.efficios.com

-- 
Sent from my mobile phone.  Please pardon any lack of formatting.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/