UBIFS and page migration (take 3)

[Richard Weinberger]

Am 17.05.2016 um 13:27 schrieb Richard Weinberger:
> Vlastimil,
> 
> Am 16.05.2016 um 15:03 schrieb Vlastimil Babka:
>> On 05/16/2016 02:44 PM, Richard Weinberger wrote:
>>> MM folks, do we have a way to force page migration?
>>
>> On NUMA we have migrate_pages(2).
> 
> Doesn't this only migrate process (user) pages?
> AFAIK we need a way to force migration of pages which
> are in the page cache.

While migrate_pages(2) does not seem to hit the ->migratepage()
function, echo 1 > /proc/sys/vm/compact_memory does.
Thanks Vlastimil for pointing me in the right direction!

Just reproduce the issue on UBIFS in a KVM guest and a
simulated NAND. :-)
Let's see whether I can come up with a generic test.

Thanks,
//richard