Re: [PATCH v14 062/138] mm/migrate: Add folio_migrate_copy()

Matthew Wilcox
2021-08-13T04:16:54Z

On Thu, Aug 12, 2021 at 01:56:24PM +0200, Vlastimil Babka wrote:
> On 7/15/21 5:35 AM, Matthew Wilcox (Oracle) wrote:
> > This is the folio equivalent of migrate_page_copy(), which is retained
> > as a wrapper for filesystems which are not yet converted to folios.
> > Also convert copy_huge_page() to folio_copy().
> >
> > Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
>
> Acked-by: Vlastimil Babka <vbabka@suse.cz>
>
> The way folio_copy() avoids cond_resched() for single page would IMHO deserve a
> comment though, so it's not buried only in this thread.

I think folio_copy() deserves kernel-doc.

/**
* folio_copy - Copy the contents of one folio to another.
* @dst: Folio to copy to.
* @src: Folio to copy from.
*
* The bytes in the folio represented by @src are copied to @dst.
* Assumes the caller has validated that @dst is at least as large as @src.
* Can be called in atomic context for order-0 folios, but if the folio is
* larger, it may sleep.
*/