Re: [PATCH v2 08/13] mm/sparse: move __highest_used_section_nr handling

[David Hildenbrand (Arm)]

On 9/22/26 06:24, Oscar Salvador (SUSE) wrote:
> On Mon, Sep 21, 2026 at 09:59:00PM +0200, David Hildenbrand (Arm) wrote:
>> In preparation for removing __section_mark_present(), let's move
>> __highest_used_section_nr handling into its callers. Verify in
>> sparse_init_one_section() that it was properly updated.
>>
>> In sparse_sections_init() we can just set it to the last processed
>> section_nr.
>>
>> No functional change intended.
>>
>> Reviewed-by: Mike Rapoport (Microsoft) <rppt@xxxxxxxxxx>
>> Signed-off-by: David Hildenbrand (Arm) <david@xxxxxxxxxx>
> 
> Acked-by: Oscar Salvador <osalvador@xxxxxxx>
> 
>> ---
> ...
>> --- a/mm/sparse.h
>> +++ b/mm/sparse.h
>> @@ -26,6 +26,7 @@ static inline void sparse_init_one_section(struct mem_section *ms,
>>  	unsigned long coded_mem_map;
>>  
>>  	BUILD_BUG_ON(SECTION_MAP_LAST_BIT > PFN_SECTION_SHIFT);
>> +	VM_WARN_ON_ONCE(section_nr > __highest_used_section_nr);
> 
> I wonder, have we seen this in the wild?

No, it would be highly unexpected (thus VM_WARN_ON_ONCE).

Thanks!

-- 
Cheers,

David