[RFC] eal: allow worker lcore stacks to be allocated from hugepage memory

[Don Wallwork]

On 4/26/2022 10:58 AM, Stephen Hemminger wrote:
> On Tue, 26 Apr 2022 08:19:59 -0400
> Don Wallwork <donw at xsightlabs.com> wrote:
>
>> Add support for using hugepages for worker lcore stack memory.  The
>> intent is to improve performance by reducing stack memory related TLB
>> misses and also by using memory local to the NUMA node of each lcore.
>>
>> Platforms desiring to make use of this capability must enable the
>> associated option flag and stack size settings in platform config
>> files.
>> ---
>>   lib/eal/linux/eal.c | 39 +++++++++++++++++++++++++++++++++++++++
>>   1 file changed, 39 insertions(+)
>>
> Good idea but having a fixed size stack makes writing complex application
> more difficult. Plus you lose the safety of guard pages.

Thanks for the quick reply.

The expectation is that use of this optional feature would be limited to 
cases where
the performance gains justify the implications of these tradeoffs. For 
example, a specific
data plane application may be okay with limited stack size and could be 
tested to ensure
stack usage remains within limits.

Also, since this applies only to worker threads, the main thread would 
not be impacted
by this change.