diff mbox series

[v4,2/2] block: unpin user pages belonging to a folio

Message ID 20240605092455.20435-3-kundan.kumar@samsung.com (mailing list archive)
State New, archived
Headers show
Series block: add larger order folio instead of pages | expand

Commit Message

Kundan Kumar June 5, 2024, 9:24 a.m. UTC
Unpin pages which belong to same folio. This enables us to release folios
on I/O completion rather than looping through pages.

Suggested-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Kundan Kumar <kundan.kumar@samsung.com>
---
 block/bio.c | 13 ++++---------
 1 file changed, 4 insertions(+), 9 deletions(-)

Comments

Matthew Wilcox June 5, 2024, 9:22 p.m. UTC | #1
On Wed, Jun 05, 2024 at 02:54:55PM +0530, Kundan Kumar wrote:
> -		page = folio_page(fi.folio, fi.offset / PAGE_SIZE);
> -		nr_pages = (fi.offset + fi.length - 1) / PAGE_SIZE -
> -			   fi.offset / PAGE_SIZE + 1;
> -		do {
> -			bio_release_page(bio, page++);
> -		} while (--nr_pages != 0);
> +		bio_release_page(bio, &fi.folio->page);
>  	}

Why can't we have ...

		bio_release_folio(bio, fi.folio, nr_pages);

which is implemented as:

static inline void bio_release_page(struct bio *bio, struct folio *folio, unsigned long nr_pages)
{
	if (bio_flagged(bio, BIO_PAGE_PINNED))
		gup_put_folio(folio, nr_pages, FOLL_PIN);
}

Sure, we'd need to make gup_put_folio() unstatic, but this seems far
more sensible.
Christoph Hellwig June 6, 2024, 4:58 a.m. UTC | #2
On Wed, Jun 05, 2024 at 10:22:11PM +0100, Matthew Wilcox wrote:
> Why can't we have ...
> 
> 		bio_release_folio(bio, fi.folio, nr_pages);
> 
> which is implemented as:
> 
> static inline void bio_release_page(struct bio *bio, struct folio *folio, unsigned long nr_pages)
> {
> 	if (bio_flagged(bio, BIO_PAGE_PINNED))
> 		gup_put_folio(folio, nr_pages, FOLL_PIN);
> }
> 
> Sure, we'd need to make gup_put_folio() unstatic, but this seems far
> more sensible.

Yes.  Although maybe a unpin_user_folio wrapper that hides the FOLL_PIN
which we're trying to keep private would be the slightly nicer variant.
diff mbox series

Patch

diff --git a/block/bio.c b/block/bio.c
index 7857b9ca5957..28418170a14a 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -1166,20 +1166,12 @@  void __bio_release_pages(struct bio *bio, bool mark_dirty)
 	struct folio_iter fi;
 
 	bio_for_each_folio_all(fi, bio) {
-		struct page *page;
-		size_t nr_pages;
-
 		if (mark_dirty) {
 			folio_lock(fi.folio);
 			folio_mark_dirty(fi.folio);
 			folio_unlock(fi.folio);
 		}
-		page = folio_page(fi.folio, fi.offset / PAGE_SIZE);
-		nr_pages = (fi.offset + fi.length - 1) / PAGE_SIZE -
-			   fi.offset / PAGE_SIZE + 1;
-		do {
-			bio_release_page(bio, page++);
-		} while (--nr_pages != 0);
+		bio_release_page(bio, &fi.folio->page);
 	}
 }
 EXPORT_SYMBOL_GPL(__bio_release_pages);
@@ -1342,6 +1334,9 @@  static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)
 		} else
 			bio_iov_add_folio(bio, folio, len, folio_offset);
 
+		if (bio_flagged(bio, BIO_PAGE_PINNED) && num_pages > 1)
+			unpin_user_pages(pages + i, num_pages - 1);
+
 		/* Skip the pages which got added */
 		i = i + (num_pages - 1);