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

[Alex Shi]

在 2020/8/7 下午10:51, Alexander Duyck 写道:
> I wonder if this entire section shouldn't be restructured. This is the
> only spot I can see where we are resetting the LRU flag instead of
> pulling the page from the LRU list with the lock held. Looking over
> the code it seems like something like that should be possible. I am
> not sure the LRU lock is really protecting us in either the
> PageCompound check nor the skip bits. It seems like holding a
> reference on the page should prevent it from switching between
> compound or not, and the skip bits are per pageblock with the LRU bits
> being per node/memcg which I would think implies that we could have
> multiple LRU locks that could apply to a single skip bit.

Hi Alexander,

I don't find problem yet on compound or skip bit usage. Would you clarify the
issue do you concerned? 

Thanks!