Re: [PATCH v10 05/14] unwind_user/deferred: Add unwind cache

[Peter Zijlstra]

On Thu, Jun 19, 2025 at 04:47:14AM -0400, Steven Rostedt wrote:
> On Thu, 19 Jun 2025 09:56:11 +0200
> Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
> 
> > Well, the trivial solution is to make it 511 and call it a day. Don't
> > make things complicated if you don't have to.
> 
> I don't know if this is more complicated, but it should make it fit
> nicely in a page:
> 
>   /* Make the cache fit in a page */
>   #define UNWIND_MAX_ENTRIES                                      \
>         ((PAGE_SIZE - sizeof(struct unwind_cache)) / sizeof(long))

Right, that's the fancy way of spelling 511 :-) Except on 32bit, where
it now spells 1023 instead.

Did you want that bitness difference?

Also, you ready for some *reaaally* big numbers on Power/ARM with 64K
pages? :-)