Re: [PATCH v8 1/5] mm: introduce a common interface for balloonpages mobility

From: Michael S. Tsirkin
Date: Thu Aug 23 2012 - 12:24:09 EST


On Thu, Aug 23, 2012 at 04:53:28PM +0300, Michael S. Tsirkin wrote:
> Basically it was very simple: we assumed page->lru was never
> touched for an allocated page, so it's safe to use it for
> internal book-keeping by the driver.
>
> Now, this is not the case anymore, you add some logic in mm/ that might
> or might not touch page->lru depending on things like reference count.

Another thought: would the issue go away if balloon used
page->private to link pages instead of LRU?
mm core could keep a reference on page to avoid it
being used while mm handles it (maybe it does already?).

If we do this, will not the only change to balloon be to tell mm that it
can use compaction for these pages when it allocates the page: using
some GPF flag or a new API?

--
MST
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