Re: [linux-next:master 5002/7443] include/linux/compiler_types.h:357:45: error: call to '__compiletime_assert_474' declared with attribute error: BUILD_BUG_ON failed: PERCPU_DYNAMIC_EARLY_SIZE < NR_KMALLOC_TYPES * KMALLOC_SHIFT_HIGH * sizeof(struct kmem_cache_cpu)

[Vlastimil Babka <vbabka@suse.cz>]

On 11/18/22 20:08, Dennis Zhou wrote:
> On Fri, Nov 18, 2022 at 10:49:43AM +0100, Vlastimil Babka wrote:
>> > 
>> > I think I might be overindexing on the out of tree modifications here.
>> > Currently, I think it's clear how modifying PERCPU_DYNAMIC_RESERVE
>> > affects the system with the lower bound being dictated by
>> > PERCPU_DYNAMIC_EARLY_SIZE. If we bump PERCPU_DYNAMIC_EARLY_SIZE, it's
>> > not inherently obvious you can drop that value lower depending on your
>> > system config.
>> > 
>> > Ultimately, it is only a few pages, so is saving it that big of a deal
>> > today? Likely not, just a bit wasteful to potentially orphan a few extra
>> > pages unnecessarily.
>> > 
>> > Let's just fix this now and I can massage this in the future if anything
>> > comes up. I appreciate you taking the time to have this discussion with
>> > me.
>> > 
>> > Vlastimil, can you please pick up this fix.
>> 
>> Sorry, got a bit lost, so do you mean the original uncoditional bump, or the
>> modification with BITS_PER_LONG > 32 (or PAGE_SHIFT > 12)?
>> 
> 
> No I've made this more complicated than necessary. Please pick up the
> original unconditional bump.
> 
> There's a small chance you'll see a merge conflict in my percpu#for-6.2
> tree:
> d667c94962c1 ("mm/percpu: remove unused PERCPU_DYNAMIC_EARLY_SLOTS")

Thanks, picked up.

> Thanks,
> Dennis
> 
>> > Acked-by: Dennis Zhou <dennis@kernel.org>
>> > 
>> > Thanks,
>> > Dennis