Re: Page migration issue with UBIFS

[Richard Weinberger]

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?
> 
> http://www.spinics.net/lists/linux-fsdevel/msg79531.html

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?

Thanks,
//richard