[PATCH v7 1/5] drivers/base/node: Optimize memory block registration to reduce boot time

[David Hildenbrand]

On 04.06.25 05:07, Andrew Morton wrote:
> On Wed, 28 May 2025 12:18:00 -0500 Donet Tom <donettom at linux.ibm.com> wrote:
> 
>> During node device initialization, `memory blocks` are registered under
>> each NUMA node. The `memory blocks` to be registered are identified using
>> the node’s start and end PFNs, which are obtained from the node's pg_data
> 
> It's quite unconventional to omit the [0/N] changelog.  This omission
> somewhat messed up my processes so I added a one-liner to this.
> 

Yeah, I was assuming that I simply did not get cc'ed on the cover 
letter, but there is actually none.

Donet please add that in the future. git can do this using --cover-letter.

>>
>> ...
>>
>> Test Results on My system with 32TB RAM
>> =======================================
>> 1. Boot time with CONFIG_DEFERRED_STRUCT_PAGE_INIT enabled.
>>
>> Without this patch
>> ------------------
>> Startup finished in 1min 16.528s (kernel)
>>
>> With this patch
>> ---------------
>> Startup finished in 17.236s (kernel) - 78% Improvement
> 
> Well someone is in for a nice surprise.
> 
>> 2. Boot time with CONFIG_DEFERRED_STRUCT_PAGE_INIT disabled.
>>
>> Without this patch
>> ------------------
>> Startup finished in 28.320s (kernel)
> 
> what.  CONFIG_DEFERRED_STRUCT_PAGE_INIT is supposed to make bootup
> faster.

Right, that's weird. Especially that it is still slower after these changes.

CONFIG_DEFERRED_STRUCT_PAGE_INIT should be initializing in parallel 
which ... should be faster.

@Donet, how many CPUs and nodes does your system have? Can you identify 
what is taking longer than without CONFIG_DEFERRED_STRUCT_PAGE_INIT?

-- 
Cheers,

David / dhildenb