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From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
To: akpm@linux-foundation.org
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	linux-fsdevel@vger.kernel.org, Zi Yan <ziy@nvidia.com>,
	Christoph Hellwig <hch@lst.de>, Jeff Layton <jlayton@kernel.org>,
	"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
	Vlastimil Babka <vbabka@suse.cz>,
	William Kucharski <william.kucharski@oracle.com>,
	David Howells <dhowells@redhat.com>
Subject: [PATCH v13 08/32] mm: Add folio_get()
Date: Mon, 12 Jul 2021 20:01:40 +0100	[thread overview]
Message-ID: <20210712190204.80979-9-willy@infradead.org> (raw)
In-Reply-To: <20210712190204.80979-1-willy@infradead.org>

If we know we have a folio, we can call folio_get() instead
of get_page() and save the overhead of calling compound_head().
No change to generated code.

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>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Reviewed-by: David Howells <dhowells@redhat.com>
---
 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 c981e3b28eb0..4a0d61a0c376 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1222,18 +1222,26 @@ 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)
+
+/**
+ * folio_get - 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,
+ * folio_try_get() may be the right interface for you to use.
+ */
+static inline void folio_get(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);
+	folio_get(page_folio(page));
 }
 
 bool __must_check try_grab_page(struct page *page, unsigned int flags);
-- 
2.30.2


  parent reply	other threads:[~2021-07-12 19:06 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-12 19:01 [PATCH v13a 00/32] Memory folios Matthew Wilcox (Oracle)
2021-07-12 19:01 ` [PATCH v13 01/32] mm: Convert get_page_unless_zero() to return bool Matthew Wilcox (Oracle)
2021-07-12 19:01 ` [PATCH v13 02/32] mm: Introduce struct folio Matthew Wilcox (Oracle)
2021-07-12 19:01 ` [PATCH v13 03/32] mm: Add folio_pgdat(), folio_zone() and folio_zonenum() Matthew Wilcox (Oracle)
2021-07-12 19:01 ` [PATCH v13 04/32] mm/vmstat: Add functions to account folio statistics Matthew Wilcox (Oracle)
2021-07-12 19:01 ` [PATCH v13 05/32] mm/debug: Add VM_BUG_ON_FOLIO() and VM_WARN_ON_ONCE_FOLIO() Matthew Wilcox (Oracle)
2021-07-12 19:01 ` [PATCH v13 06/32] mm: Add folio reference count functions Matthew Wilcox (Oracle)
2021-07-12 19:01 ` [PATCH v13 07/32] mm: Add folio_put() Matthew Wilcox (Oracle)
2021-07-12 19:01 ` Matthew Wilcox (Oracle) [this message]
2021-07-12 19:01 ` [PATCH v13 09/32] mm: Add folio_try_get_rcu() Matthew Wilcox (Oracle)
2021-07-12 19:01 ` [PATCH v13 10/32] mm: Add folio flag manipulation functions Matthew Wilcox (Oracle)
2021-07-12 19:01 ` [PATCH v13 11/32] mm/lru: Add folio LRU functions Matthew Wilcox (Oracle)
2021-07-12 19:01 ` [PATCH v13 12/32] mm: Handle per-folio private data Matthew Wilcox (Oracle)
2021-07-12 19:01 ` [PATCH v13 13/32] mm/filemap: Add folio_index(), folio_file_page() and folio_contains() Matthew Wilcox (Oracle)
2021-07-12 19:01 ` [PATCH v13 14/32] mm/filemap: Add folio_next_index() Matthew Wilcox (Oracle)
2021-07-12 19:01 ` [PATCH v13 15/32] mm/filemap: Add folio_pos() and folio_file_pos() Matthew Wilcox (Oracle)
2021-07-12 19:01 ` [PATCH v13 16/32] mm/util: Add folio_mapping() and folio_file_mapping() Matthew Wilcox (Oracle)
2021-07-12 19:01 ` [PATCH v13 17/32] mm/filemap: Add folio_unlock() Matthew Wilcox (Oracle)
2021-07-12 19:01 ` [PATCH v13 18/32] mm/filemap: Add folio_lock() Matthew Wilcox (Oracle)
2021-07-12 19:01 ` [PATCH v13 19/32] mm/filemap: Add folio_lock_killable() Matthew Wilcox (Oracle)
2021-07-12 19:01 ` [PATCH v13 20/32] mm/filemap: Add __folio_lock_async() Matthew Wilcox (Oracle)
2021-07-12 19:01 ` [PATCH v13 21/32] mm/filemap: Add folio_wait_locked() Matthew Wilcox (Oracle)
2021-07-12 19:01 ` [PATCH v13 22/32] mm/filemap: Add __folio_lock_or_retry() Matthew Wilcox (Oracle)
2021-07-12 19:01 ` [PATCH v13 23/32] mm/swap: Add folio_rotate_reclaimable() Matthew Wilcox (Oracle)
2021-07-12 19:01 ` [PATCH v13 24/32] mm/filemap: Add folio_end_writeback() Matthew Wilcox (Oracle)
2021-07-12 19:01 ` [PATCH v13 25/32] mm/writeback: Add folio_wait_writeback() Matthew Wilcox (Oracle)
2021-07-12 19:01 ` [PATCH v13 26/32] mm/writeback: Add folio_wait_stable() Matthew Wilcox (Oracle)
2021-07-12 19:01 ` [PATCH v13 27/32] mm/filemap: Add folio_wait_bit() Matthew Wilcox (Oracle)
2021-07-12 19:02 ` [PATCH v13 28/32] mm/filemap: Add folio_wake_bit() Matthew Wilcox (Oracle)
2021-07-12 19:02 ` [PATCH v13 29/32] mm/filemap: Convert page wait queues to be folios Matthew Wilcox (Oracle)
2021-07-12 19:02 ` [PATCH v13 30/32] mm/filemap: Add folio private_2 functions Matthew Wilcox (Oracle)
2021-07-12 19:02 ` [PATCH v13 31/32] fs/netfs: Add folio fscache functions Matthew Wilcox (Oracle)
2021-07-12 19:02 ` [PATCH v13 32/32] mm: Add folio_mapped() Matthew Wilcox (Oracle)

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