Re: [PATCH v6 3/6] mm/page_alloc: add support for initializing pageblock as isolated.

[Zi Yan <ziy@nvidia.com>]

On 30 May 2025, at 13:06, Vlastimil Babka wrote:

> On 5/30/25 18:22, Zi Yan wrote:
>> MIGRATE_ISOLATE is a standalone bit, so a pageblock cannot be initialized
>> to just MIGRATE_ISOLATE. Add init_pageblock_migratetype() to enable
>> initialize a pageblock with a migratetype and isolated.
>>
>> Signed-off-by: Zi Yan <ziy@nvidia.com>
>> Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
>
>> +void __meminit init_pageblock_migratetype(struct page *page,
>> +					  enum migratetype migratetype,
>> +					  bool isolate)
>> +{
>> +	unsigned long mask = MIGRATETYPE_MASK;
>> +	unsigned long flags = migratetype;
>> +
>> +	if (unlikely(page_group_by_mobility_disabled &&
>> +		     migratetype < MIGRATE_PCPTYPES))
>> +		migratetype = MIGRATE_UNMOVABLE;
>> +
>> +#ifdef CONFIG_MEMORY_ISOLATION
>> +	if (migratetype == MIGRATE_ISOLATE) {
>> +		VM_WARN_ONCE(
>> +			1,
>> +			"Set isolate=true to isolate pageblock with a migratetype");
>> +		return;
>> +	}
>> +	if (isolate) {
>> +		mask = MIGRATETYPE_AND_ISO_MASK;
>> +		flags |= BIT(PB_migrate_isolate);
>> +	}
>> +#endif
>> +	__set_pfnblock_flags_mask(page, page_to_pfn(page), flags, mask);
>
> Nit: I think this could have also used MIGRATETYPE_AND_ISO_MASK unconditionally?

Yes, let me send a fixup patch. Thanks for spotting it.

>> +}
>> +
>>  #ifdef CONFIG_DEBUG_VM
>>  static int page_outside_zone_boundaries(struct zone *zone, struct page *page)
>>  {


Best Regards,
Yan, Zi