svn commit: r241889 - in user/andre/tcp_workqueue/sys: arm/arm cddl/compat/opensolaris/kern cddl/contrib/opensolaris/uts/common/dtrace cddl/contrib/opensolaris/uts/common/fs/zfs ddb dev/acpica dev/...

[Andre Oppermann]

On 28.10.2012 22:32, Attilio Rao wrote:
> On Sun, Oct 28, 2012 at 9:20 PM, Andre Oppermann <andre at freebsd.org> wrote:
>> On 28.10.2012 18:42, Attilio Rao wrote:
>>>
>>> On Sat, Oct 27, 2012 at 5:27 PM, Attilio Rao <attilio at freebsd.org> wrote:
>>>>
>>>> Here we go with further comments tweaks.
>>>> Also, in order to make it a complete NOP from KPI perspective I had to
>>>> change the way the mtx_assert() wrapper was implemented as in v1 it
>>>> wasn't correctly handling the const qualifier.
>>>> I think the result is better now and you should refer to this patch for
>>>> reviews:
>>>> http://www.freebsd.org/~attilio/mtx_decoupled2.patch
>>
>>
>> Thank you for the updated patch.  If the others more versed in this
>> area are happy with it I'm not objecting.
>>
>>
>>> BTW, the mtx_sysuninit() introduction can be avoided by using this other
>>> trick:
>>> #define MTX_SYSINIT(name, mtx, desc, opts)                              \
>>>           static struct mtx_args name##_args = {                          \
>>>                   (mtx),                                                  \
>>>                   (desc),                                                 \
>>>                   (opts)                                                  \
>>>           };                                                              \
>>>           SYSINIT(name##_mtx_sysinit, SI_SUB_LOCK, SI_ORDER_MIDDLE,       \
>>>               mtx_sysinit, &name##_args);                                 \
>>>           SYSUNINIT(name##_mtx_sysuninit, SI_SUB_LOCK, SI_ORDER_MIDDLE,   \
>>>               _mtx_destroy, __DEVOLATILE(void *, &(mtx)->mtx_lock))
>>>
>>> I'm just not sure that I would like the use of __DEVOLATILE() even if
>>> it would help in this case when introducing MTX_SYSINIT_UNSHARE()
>>> because we will just need to reuse the same code.
>>
>>
>> I'm not really happy about the _unshare naming.  Something like
>> _aligned or _cachline would be much more obvious on what it does.
>
> I agree. Infact if we want to apply this to ie. sx locks too _unshared
> will generate too much confusion (as already reported by Jeff too).
> I'd say _aligned is good to go.

_aligned can be slightly confusing too for someone not aware of the
differences of alignment (begin of structure aligned) and the additional
padding to a cache line.  So _cacheline is probably more expressive and
spells out what the real purpose is.

-- 
Andre