Subject: Re: [PATCH v2 7/7] memory-hotplug: tile: suitable memory should go to ZONE_MOVABLE

From: Chris Metcalf <[email-masked]>
Date: Thu, 31 Jul 2014 16:43:58 -0400

On 7/21/2014 11:09 PM, Wang Nan wrote:
> Hi Andrew,
>
> Please drop patch 7/7 from -mm tree and keep other 6 patches.
>
> arch_add_memory() in tile is different from others: no nid parameter.
> Patch 7/7 will block compiling.
>
> I cc this mail to Chris Metcalf and hope he can look at this issue.
>
> Other 6 patches looks good.
>
> On 2014/7/21 11:46, Wang Nan wrote:
>> This patch introduces zone_for_memory() to arch_add_memory() on tile to
>> ensure new, higher memory added into ZONE_MOVABLE if movable zone has
>> already setup.
>>
>> This patch also fix a problem: on tile, new memory should be added into
>> ZONE_HIGHMEM by default, not MAX_NR_ZONES-1, which is ZONE_MOVABLE.
>>
>> Signed-off-by: Wang Nan <[email-masked]>
>> Cc: Zhang Yanfei <[email-masked]>
>> Cc: Dave Hansen <[email-masked]>
>> ---
>>  arch/tile/mm/init.c | 3 ++-
>>  1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/tile/mm/init.c b/arch/tile/mm/init.c
>> index bfb3127..22ac6c1 100644
>> --- a/arch/tile/mm/init.c
>> +++ b/arch/tile/mm/init.c
>> @@ -872,7 +872,8 @@ void __init mem_init(void)
>>  int arch_add_memory(u64 start, u64 size)
>>  {
>>  	struct pglist_data *pgdata = &contig_page_data;
>> -	struct zone *zone = pgdata->node_zones + MAX_NR_ZONES-1;
>> +	struct zone *zone = pgdata->node_zones +
>> +		zone_for_memory(nid, start, size, ZONE_HIGHMEM);
>>  	unsigned long start_pfn = start >> PAGE_SHIFT;
>>  	unsigned long nr_pages = size >> PAGE_SHIFT;
>>  

This code is entirely stale; it came from the initial port of Linux
2.6.15 to Tilera.  Since we have always used DISCONTIGMEM unconditionally,
which forces NEED_MULTIPLE_NODES to be true, this code never compiles.
Note the completely irrelevant comment about x86 in this ifdef block, too :-)

The cleanest thing to do is just remove those three functions in the
ifdef block.  I'll do that to our internal tree and plan to push the
change upstream later.

-- 
Chris Metcalf, Tilera Corp.
http://www.tilera.com