Re: Page migration issue with UBIFS

From: Joonsoo Kim
Date: Thu Mar 17 2016 - 11:17:24 EST

2016-03-17 17:13 GMT+09:00 Richard Weinberger <richard@xxxxxx>:
> Am 17.03.2016 um 08:11 schrieb Joonsoo Kim:
>>> It is still not clear why UBIFS has to provide a >migratepage() and what the expected semantics
>>> are.
>>> What we know so far is that the fall back migration function is broken. I'm sure not only on UBIFS.
>>> Can CMA folks please clarify? :-)
>> Hello,
>> As you mentioned earlier, this issue would not be directly related
>> to CMA. It looks like it is more general issue related to interaction
>> between MM and FS. Your first error log shows that error happens when
>> ubifs_set_page_dirty() is called in try_to_unmap_one() which also
>> can be called by reclaimer (kswapd or direct reclaim). Quick search shows
>> that problem also happens on reclaim. Is that fixed?
> Well, this problem happened only on a tainted kernel and never popped up again.
> So, I really don't know. :-)
>> I think that you need to CC other people who understand interaction
>> between MM and FS perfectly.
> Who is missing on the CC list?

Vlastimil already added Hugh and Mel to other relevant thread but I think
this thread has more information about the problem so I add them here.