[PATCH 0/2] Allow configurable stack size (especially 32k on PPC64)

[Hamish Martin]

On 02/22/2017 09:06 PM, Benjamin Herrenschmidt wrote:
> On Wed, 2017-02-22 at 17:25 +1100, Michael Ellerman wrote:
>>
>> Thanks for the detailed explanation.
>>
>> The patches look fine, so I don't see any reason why we wouldn't merge
>> this. I might make the config option depend on EXPERT, but that's just
>> cosmetic.
>>
>>
>> You're right about the difference in stack overhead between 32 & 64-bit.
>> But I guess on the other hand we've been using 16K stacks on 64-bit for
>> over 15 years, and although we have had some reports of stack overflow
>> they're not a common problem.
>
> Right and in fact I wonder if we could generally help this for cases
> like this one (lots of stacked devices) by having the generic driver
> core break those chains by deferring new device registration to a work
> queue or kthread.
>
> That would help in a lot of cases. We do get some stupid deep chains
> in cases of many bus encapsulation.
>
> Cheers,
> Ben.
>
>
Agreed. In fact you suggested it back in 2008 somewhere in the thread I 
linked to in my cover letter for the series. That's obviously going to 
take a long time to happen, so for now I hope this series will allow 
some respite for users affected.

Thanks for your input.