Re: [RFC] mm: introduce page pinner
From: Matthew Wilcox <willy@infradead.org>
Date: 2021-12-08 14:24:21
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On Wed, Dec 08, 2021 at 07:54:35PM +0800, 胡玮文 wrote:
quoted hunk ↗ jump to hunk
@@ -406,6 +409,7 @@ int folio_migrate_mapping(struct address_space *mapping, xas_lock_irq(&xas); if (!folio_ref_freeze(folio, expected_count)) { xas_unlock_irq(&xas); + page_pinner_failure(&folio->page); return -EAGAIN; }I'm not sure what to do with the new folio, it seems using folio->page in new codes is not correct.
It's a transitional measure. Once everything that should be converted to folios has been converted, it can go away. Tail pages don't have their own refcounts, so the page pinner should actually be the folio pinner. I hadn't bothered to point this out because we're in the early days of the folio transition and it'd be unreasonable to criticise Minchan for not converting his patch from pages to folios.