Re: [PATCH v8 2/3] mm/memory hotplug/unplug: Add online_memory_block_pages() and offline_memory_block_pages()

[Mike Rapoport <rppt@kernel.org>]

Hi,

On Tue, Jan 20, 2026 at 10:33:45PM +0800, Tianyou Li wrote:
> Encapsulate the mhp_init_memmap_on_memory() and online_pages() into
> online_memory_block_pages(). Thus we can further optimize the
> set_zone_contiguous() to check the whole memory block range, instead
> of check the zone contiguous in separate range.
> 
> Correspondingly, encapsulate the mhp_deinit_memmap_on_memory() and
> offline_pages() into offline_memory_block_pages().
> 
> Tested-by: Yuan Liu <yuan1.liu@intel.com>
> Reviewed-by: Yuan Liu <yuan1.liu@intel.com>
> Signed-off-by: Tianyou Li <tianyou.li@intel.com>
> ---
>  drivers/base/memory.c          | 53 ++++++---------------------
>  include/linux/memory_hotplug.h | 18 +++++-----
>  mm/memory_hotplug.c            | 65 +++++++++++++++++++++++++++++++---
>  3 files changed, 80 insertions(+), 56 deletions(-)
> 
> diff --git a/drivers/base/memory.c b/drivers/base/memory.c
> index 751f248ca4a8..ea4d6fbf34fd 100644
> --- a/drivers/base/memory.c
> +++ b/drivers/base/memory.c
> @@ -246,31 +246,12 @@ static int memory_block_online(struct memory_block *mem)
>  		nr_vmemmap_pages = mem->altmap->free;
>  
>  	mem_hotplug_begin();
> -	if (nr_vmemmap_pages) {
> -		ret = mhp_init_memmap_on_memory(start_pfn, nr_vmemmap_pages, zone);
> -		if (ret)
> -			goto out;
> -	}
> -
> -	ret = online_pages(start_pfn + nr_vmemmap_pages,
> -			   nr_pages - nr_vmemmap_pages, zone, mem->group);
> -	if (ret) {
> -		if (nr_vmemmap_pages)
> -			mhp_deinit_memmap_on_memory(start_pfn, nr_vmemmap_pages);
> -		goto out;
> -	}
> -
> -	/*
> -	 * Account once onlining succeeded. If the zone was unpopulated, it is
> -	 * now already properly populated.
> -	 */
> -	if (nr_vmemmap_pages)
> -		adjust_present_page_count(pfn_to_page(start_pfn), mem->group,
> -					  nr_vmemmap_pages);
> -
> -	mem->zone = zone;
> -out:
> +	ret = online_memory_block_pages(start_pfn, nr_pages, nr_vmemmap_pages,
> +					zone, mem->group);
> +	if (!ret)
> +		mem->zone = zone;

I think we can move most of memory_block_online() to the new function and
pass struct memory_block to it.
I'd suggest 
	
	int mhp_block_online(struct memory_block *block)

and 

	int mhp_block_offline(struct memory_block *block)

Other than that LGTM.

>  	mem_hotplug_done();
> +
>  	return ret;
>  }
>  

-- 
Sincerely yours,
Mike.