Re: [RFC 1/7] powerpc/mm: Make vmemmap_populate accommodate ZONE_DEVICE memory

[Anshuman Khandual <khandual@linux.vnet.ibm.com>]

On 05/03/2016 01:34 PM, Balbir Singh wrote:
> 
> 
> On 03/05/16 16:29, Anshuman Khandual wrote:
>> Change the vmemmap_populate function to detect device memory through
>> to_vmemmap_altmap and then call generic the __vmmemap_alloc_block_buf
>> function instead of vmemmap_alloc_block as the earlier can allocate
>> physical memory from the device range instead of the system RAM.
>>
>> Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com>
>> ---
>>  arch/powerpc/mm/init_64.c | 6 +++++-
>>  1 file changed, 5 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c
>> index ba65566..db73708 100644
>> --- a/arch/powerpc/mm/init_64.c
>> +++ b/arch/powerpc/mm/init_64.c
>> @@ -42,6 +42,7 @@
>>  #include <linux/memblock.h>
>>  #include <linux/hugetlb.h>
>>  #include <linux/slab.h>
>> +#include <linux/memremap.h>
>>  
>>  #include <asm/pgalloc.h>
>>  #include <asm/page.h>
>> @@ -312,6 +313,7 @@ static __meminit void vmemmap_list_populate(unsigned long phys,
>>  int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node)
>>  {
>>  	unsigned long page_size = 1 << mmu_psize_defs[mmu_vmemmap_psize].shift;
>> +	unsigned long orig = start;
> 
> I would much rather do struct vmem_altmap *altmap = to_vmem_altmap(start);

Sure, makes sense.