Re: [PATCH v17 14/21] mm/compaction: do page isolation first in compaction

From: Alex Shi
Date: Wed Aug 12 2020 - 08:16:48 EST

在 2020/8/12 下午7:43, Alex Shi 写道:
>>> Sorry, I still can not follow you here. Compound code part is unchanged
>>> and follow the original logical. So would you like to pose a new code to
>>> see if its works?
>> No there are significant changes as you reordered all of the
>> operations. Prior to your change the LRU bit was checked, but not
>> cleared before testing for PageCompound. Now you are clearing it
>> before you are testing if it is a compound page. So if compaction is
>> running we will be seeing the pages in the LRU stay put, but the
>> compound bit flickering off and on if the compound page is encountered
>> with the wrong or NULL lruvec. What I was suggesting is that the

> The lruvec could be wrong or NULL here, that is the base stone of whole
> patchset.
Sorry for typo. s/could/could not/