From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
To: linux-mm@kvack.org
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-cachefs@redhat.com, linux-afs@lists.infradead.org,
Zi Yan <ziy@nvidia.com>, Christoph Hellwig <hch@lst.de>,
Jeff Layton <jlayton@kernel.org>
Subject: [PATCH v7 08/28] mm: Add get_folio
Date: Fri, 9 Apr 2021 19:50:45 +0100 [thread overview]
Message-ID: <20210409185105.188284-9-willy@infradead.org> (raw)
In-Reply-To: <20210409185105.188284-1-willy@infradead.org>
If we know we have a folio, we can call get_folio() instead
of get_page() and save the overhead of calling compound_head().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Jeff Layton <jlayton@kernel.org>
---
include/linux/mm.h | 26 +++++++++++++++++---------
1 file changed, 17 insertions(+), 9 deletions(-)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 747c6f47aef6..67d9104c1cc1 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1219,18 +1219,26 @@ static inline bool is_pci_p2pdma_page(const struct page *page)
}
/* 127: arbitrary random number, small enough to assemble well */
-#define page_ref_zero_or_close_to_overflow(page) \
- ((unsigned int) page_ref_count(page) + 127u <= 127u)
+#define folio_ref_zero_or_close_to_overflow(folio) \
+ ((unsigned int) folio_ref_count(folio) + 127u <= 127u)
+
+/**
+ * get_folio - Increment the reference count on a folio.
+ * @folio: The folio.
+ *
+ * Context: May be called in any context, as long as you know that
+ * you have a refcount on the folio. If you do not already have one,
+ * try_grab_page() may be the right interface for you to use.
+ */
+static inline void get_folio(struct folio *folio)
+{
+ VM_BUG_ON_FOLIO(folio_ref_zero_or_close_to_overflow(folio), folio);
+ folio_ref_inc(folio);
+}
static inline void get_page(struct page *page)
{
- page = compound_head(page);
- /*
- * Getting a normal page or the head of a compound page
- * requires to already have an elevated page->_refcount.
- */
- VM_BUG_ON_PAGE(page_ref_zero_or_close_to_overflow(page), page);
- page_ref_inc(page);
+ get_folio(page_folio(page));
}
bool __must_check try_grab_page(struct page *page, unsigned int flags);
--
2.30.2
next prev parent reply other threads:[~2021-04-09 18:58 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-09 18:50 [PATCH v7 00/28] Memory Folios Matthew Wilcox (Oracle)
2021-04-09 18:50 ` [PATCH v7 01/28] mm: Optimise nth_page for contiguous memmap Matthew Wilcox (Oracle)
2021-04-12 6:08 ` Christoph Hellwig
2021-04-09 18:50 ` [PATCH v7 02/28] mm: Introduce struct folio Matthew Wilcox (Oracle)
2021-04-09 22:45 ` kernel test robot
2021-04-10 2:43 ` Bogus struct page layout on 32-bit Matthew Wilcox
2021-04-10 6:21 ` Jesper Dangaard Brouer
2021-04-10 8:52 ` Ilias Apalodimas
2021-04-10 14:06 ` Matthew Wilcox
2021-04-10 15:54 ` Russell King - ARM Linux admin
2021-04-16 9:26 ` Grygorii Strashko
2021-04-16 14:10 ` Arnd Bergmann
2021-04-17 13:08 ` David Laight
2021-04-10 14:17 ` David Laight
2021-04-10 19:10 ` Arnd Bergmann
2021-04-11 22:35 ` Matthew Wilcox
2021-04-10 2:51 ` [PATCH v7 02/28] mm: Introduce struct folio kernel test robot
2021-04-16 15:55 ` Matthew Wilcox
2021-04-19 9:06 ` Kirill A. Shutemov
2021-04-09 18:50 ` [PATCH v7 03/28] mm: Add folio_pgdat and folio_zone Matthew Wilcox (Oracle)
2021-04-09 18:50 ` [PATCH v7 04/28] mm/vmstat: Add functions to account folio statistics Matthew Wilcox (Oracle)
2021-04-09 18:50 ` [PATCH v7 05/28] mm/debug: Add VM_BUG_ON_FOLIO and VM_WARN_ON_ONCE_FOLIO Matthew Wilcox (Oracle)
2021-04-09 18:50 ` [PATCH v7 06/28] mm: Add folio reference count functions Matthew Wilcox (Oracle)
2021-04-09 18:50 ` [PATCH v7 07/28] mm: Add put_folio Matthew Wilcox (Oracle)
2021-04-09 18:50 ` Matthew Wilcox (Oracle) [this message]
2021-04-09 18:50 ` [PATCH v7 09/28] mm: Create FolioFlags Matthew Wilcox (Oracle)
2021-04-19 13:25 ` Peter Zijlstra
2021-04-19 13:55 ` Matthew Wilcox
2021-04-09 18:50 ` [PATCH v7 10/28] mm: Handle per-folio private data Matthew Wilcox (Oracle)
2021-04-09 18:50 ` [PATCH v7 11/28] mm/filemap: Add folio_index, folio_file_page and folio_contains Matthew Wilcox (Oracle)
2021-04-09 18:50 ` [PATCH v7 12/28] mm/filemap: Add folio_next_index Matthew Wilcox (Oracle)
2021-04-09 18:50 ` [PATCH v7 13/28] mm/filemap: Add folio_offset and folio_file_offset Matthew Wilcox (Oracle)
2021-04-09 18:50 ` [PATCH v7 14/28] mm/util: Add folio_mapping and folio_file_mapping Matthew Wilcox (Oracle)
2021-04-09 18:50 ` [PATCH v7 15/28] mm: Add folio_mapcount Matthew Wilcox (Oracle)
2021-04-09 18:50 ` [PATCH v7 16/28] mm/memcg: Add folio wrappers for various functions Matthew Wilcox (Oracle)
2021-04-09 18:50 ` [PATCH v7 17/28] mm/filemap: Add unlock_folio Matthew Wilcox (Oracle)
2021-04-09 18:50 ` [PATCH v7 18/28] mm/filemap: Add lock_folio Matthew Wilcox (Oracle)
2021-04-09 18:50 ` [PATCH v7 19/28] mm/filemap: Add lock_folio_killable Matthew Wilcox (Oracle)
2021-04-09 18:50 ` [PATCH v7 20/28] mm/filemap: Add __lock_folio_async Matthew Wilcox (Oracle)
2021-04-09 18:50 ` [PATCH v7 21/28] mm/filemap: Add __lock_folio_or_retry Matthew Wilcox (Oracle)
2021-04-09 18:50 ` [PATCH v7 22/28] mm/filemap: Add wait_on_folio_locked Matthew Wilcox (Oracle)
2021-04-09 18:51 ` [PATCH v7 23/28] mm/filemap: Add end_folio_writeback Matthew Wilcox (Oracle)
2021-04-09 18:51 ` [PATCH v7 24/28] mm/writeback: Add wait_on_folio_writeback Matthew Wilcox (Oracle)
2021-04-09 18:51 ` [PATCH v7 25/28] mm/writeback: Add wait_for_stable_folio Matthew Wilcox (Oracle)
2021-04-09 18:51 ` [PATCH v7 26/28] mm/filemap: Convert wait_on_page_bit to wait_on_folio_bit Matthew Wilcox (Oracle)
2021-04-09 18:51 ` [PATCH v7 27/28] mm/filemap: Convert wake_up_page_bit to wake_up_folio_bit Matthew Wilcox (Oracle)
2021-04-09 18:51 ` [PATCH v7 28/28] mm/filemap: Convert page wait queues to be folios Matthew Wilcox (Oracle)
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210409185105.188284-9-willy@infradead.org \
--to=willy@infradead.org \
--cc=hch@lst.de \
--cc=jlayton@kernel.org \
--cc=linux-afs@lists.infradead.org \
--cc=linux-cachefs@redhat.com \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=ziy@nvidia.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).