[RFC] nptl: change default stack guard size of threads

[Florian Weimer]

On 12/19/2017 01:34 PM, James Greenhalgh wrote:

> Option 1: 64k guard pages for LP64 on AArch64.

> Option 2: 4k guard pages for LP64 for AArch64

> Our proposal then, having spoken things through with the Arm engineers
> here, and taken in to consideration the opinions on this thread, is that
> we move to two "blessed" configurations of the GCC support for AArch64.

Are there any Arm engineers who prefer Option 2, or is that just there 
to accommodate feedback on libc-alpha?

My main concern was the variance in configurations with Option 1 
(compared to Option 2).  To some extent, the variance with Option 1 is 
temporary.  If both Option 1 and 2 are offered, we have permanent 
variance.  From my point of view, that's worth that just going with 
Option 1.

So if this is some sort of consensus proposal, as opposed to actual 
technical requirements which favor Option 2 in some deployments, I think 
that's not a good idea, and we should go with Option 1 instead.

Thanks,
Florian