Re: [PATCH] mm: use pagevec to rotate reclaimable page

Hisashi Hifumi
2007-09-14T07:42:58Z

Thank you for your comment.

At 11:37 07/09/14, Andrew Morton wrote:

>The page_count() test here is a bit of a worry, too. Why do we need it?
>The caller must have pinned the page in some fashion else we couldn't use
>it safely in this function at all.
>
>I assume that you discovered that once we've cleared PageWriteback(), the
>page can get reclaimed elsewhere? If so, that could still happen
>immediately after the page_count() test. It's all a bit of a worry.
>Deferring the ClearPageWriteback() will fix any race concerns, but I do
>think that we need to take a ref on the page for the pagevec ownership.
>

Actually, I considered taking a ref to pin pages. But this could prevent
the page
reclaiming activity so I did not use it.

I reflect your comment and send you modified patch.