Re: [PATCH] mm/mempool: use static key for boot-time debug enablement

[Vlastimil Babka (SUSE)]

On 5/27/26 22:06, Andrew Morton wrote:
> On Wed, 27 May 2026 06:46:34 -0400 lirongqing <lirongqing@xxxxxxxxx> wrote:
> 
>> Replace the #ifdef CONFIG_SLUB_DEBUG_ON conditional compilation with a
>> static key (mempool_debug_enabled). This allows enabling mempool debugging
>> at boot time via:
>> 
>>     mempool_debug
>> 
>> Instead of requiring CONFIG_SLUB_DEBUG_ON at compile time. Benefits:
> 
> Sashiko is suggesting that we use mempool_debug=<...> here.  Which permits
> mempool_debug=n if for some reason the kernel is defaulting to "on".  Which
> we might choose to do in the future.   I think that's a little better - do others agree?

Yeah we could do that. But I still think "CONFIG_SLUB_DEBUG_ON" isn't what
should cause mempool_debug to default to "on". It can be revisited once
there's a solid argument why default on would be needed.

> Same goes for the new dmapool_debug.

Ack.

> Sashiko asked a second question:
> 	https://sashiko.dev/#/patchset/20260527104634.2434-1-lirongqing@xxxxxxxxx

Seems the same thing as Usama raised about static key init ordering.