Re: [PATCH v10 2/5] mm: Add helper to convert HMM pfn to migrate pfn

[David Hildenbrand (Arm)]

>>
>>> +
>>> +		migrate->src[i] |= (pfn & HMM_PFN_WRITE) ? MIGRATE_PFN_WRITE : 0;
>>> +		migrate->src[i] |= (pfn & HMM_PFN_COMPOUND) ? MIGRATE_PFN_COMPOUND : 0;
>>> +		migrate->dst[i] = 0;
>>> +	}
>>> +
>>> +	if (migrate->cpages)
>>> +		migrate_vma_unmap(migrate);
>> Can you remind me why we do this here, in the setup() phase? The function doc
>> does not really describe that.
> 
> It is to be in par what migrate_vma_setup() does today after the "collect" phase.
> 

Ah, okay. How the whole machinery works is still a bit of a mystery for me :)

-- 
Cheers,

David