Re: [PATCH 1/2] mm: hugetlb: add hugetlb_alloc_threads cmdline option

[Thomas Prescher]

On Sat, 2025-02-22 at 18:46 -0800, Andrew Morton wrote:
> 
> I'm all for auto-tuning but yeah, for a boot-time thing like this we
> require a boot-time knob.
> 
> As is often (always) the case, the sad thing is that about five
> people
> in the world know that this exists.  How can we tell our users that
> this new thing is available and possibly useful to them?  We have no
> channel.
> 
> Perhaps in your [2/2] we could be noisier?  
> 
> 	HugeTLB: allocation took 4242ms with
> hugepage_alloc_threads=42
> 
> and with a facility level higher than KERN_DEBUG (can/should we use
> pr_foo() here, btw?).  That should get people curious and poking
> around
> in the documentation and experimenting.

I completely agree with what you are saying. So for v2, I would:

a) change the default from 2 threads per node to 25% of the total
threads per node to make it faster for everyone

b) make it noisier by using pr_info instead of printk(KERN_DEBUG ...)
and also print the number of threads that are used

Anything that I am missing here?