On 2017/1/17 18:25, Michal Hocko wrote:
> On Mon 16-01-17 21:38:05, zhongjiang wrote:
>> From: zhong jiang <zhongjiang@xxxxxxxxxx>
>>
>> At present, we skip the reservation storage by the driver for
>> the zone_dvice. but the free pages set aside for the memmap is
>> ignored. And since the free pages is only used as the memmap,
>> so we can also skip the corresponding pages.
> I have really hard time to understand what this patch does and why it
> matters. Could you please rephrase the changelog to state, the problem,
> how it affects users and what is the fix please?
>
Hi, Michal
The patch maybe incorrect if free pages for memmap mapping is accouted for zone_device.
I am just a little confusing about the implement. it maybe simple and stupid.
first pfn for dev_mappage come from vmem_altmap_offset, and free pages reserved for
memmap mapping need to be accounted. I do not know the meaning.
Another issue is in sparse_remove_one_section. A section belongs to zone_device is not
always need to consider the map_offset. is it right ? From pfn_first to end , that section
should no need to consider the map_offet.
Thanks
zhongjiang
>> Signed-off-by: zhong jiang <zhongjiang@xxxxxxxxxx>
>> ---
>> mm/page_alloc.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
>> index d604d25..51d8d03 100644
>> --- a/mm/page_alloc.c
>> +++ b/mm/page_alloc.c
>> @@ -5047,7 +5047,7 @@ void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
>> * memory
>> */
>> if (altmap && start_pfn == altmap->base_pfn)
>> - start_pfn += altmap->reserve;
>> + start_pfn += vmem_altmap_offset(altmap);
>>
>> for (pfn = start_pfn; pfn < end_pfn; pfn++) {
>> /*
>> --
>> 1.8.3.1
>>
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxx. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>