Hi Vineet,
On Thu, 2017-11-30 at 09:46 -0800, Vineet Gupta wrote:
> On 11/29/2017 12:21 AM, Alexey Brodkin wrote:
> > As of today we assumed that "machine_desc->init_per_cpu" calls
> > are only usable on SMP systems when we want to run some piece of
> > code on early boot for each and every core, I guess assumption was
> > we have "machine_desc->init_early" for single-core cases where
> > the one and only master core can do all the things.
> >
> > But it turned out for platforms which might be both UP and SMP it
> > might be benificial to use "init_per_cpu" for both UP and SMP cases
> > with which we achieve 2 things simultaneously:
> > 1) Exactly the same one code will be used for UP&SMP for
> > things required to be done on each an every core regardless if it's
> > a master and the only core in UP system or any other slave core in SMP
> > setup.
> > 1) There will be no "ifdef CONFIG_SMP" around "init_per_cpu".
> >
>
> Seems fine to me. However this needs to go with the actual platform change which
> needs it.
Well for example this might get in the way of building kernel for HSDK with
CONFIG_SMP disabled which is IMHO quite valid case in terms of testing
code-base compiled with no CONFIG_SMP (something Waldemar was up to).
Is it a strong enough reason for that patch to be applied?
-Alexey
On 06/14/2018 03:26 PM, Alexey Brodkin wrote:
> Hi Vineet,
>
> On Thu, 2017-11-30 at 09:46 -0800, Vineet Gupta wrote:
>> On 11/29/2017 12:21 AM, Alexey Brodkin wrote:
>>> As of today we assumed that "machine_desc->init_per_cpu" calls
>>> are only usable on SMP systems when we want to run some piece of
>>> code on early boot for each and every core, I guess assumption was
>>> we have "machine_desc->init_early" for single-core cases where
>>> the one and only master core can do all the things.
>>>
>>> But it turned out for platforms which might be both UP and SMP it
>>> might be benificial to use "init_per_cpu" for both UP and SMP cases
>>> with which we achieve 2 things simultaneously:
>>> 1) Exactly the same one code will be used for UP&SMP for
>>> things required to be done on each an every core regardless if it's
>>> a master and the only core in UP system or any other slave core in SMP
>>> setup.
>>> 1) There will be no "ifdef CONFIG_SMP" around "init_per_cpu".
>>>
>> Seems fine to me. However this needs to go with the actual platform change which
>> needs it.
> Well for example this might get in the way of building kernel for HSDK with
> CONFIG_SMP disabled which is IMHO quite valid case in terms of testing
> code-base compiled with no CONFIG_SMP
Fair enough - although world is moving away from UP.
> (something Waldemar was up to).
Really, why does he care if we are running SMP kernel - oh his simulation time
goes up. But honestly he should try and use the SMP kernel for testing as that
might uncover any system wide / SMP specific bugs in testing uclibc as well !
> Is it a strong enough reason for that patch to be applied?
Well per my original reply I didn't have any objections for this per-se and wanted
to see the platform patch. Seems we don't need platform patch as it is not under
#ifdef in hsdk/platform.c
I'll queue this up !
-Vineet