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>
Subject: [PATCH v5 09/27] mm: Add get_folio
Date: Sat, 20 Mar 2021 05:40:46 +0000 [thread overview]
Message-ID: <20210320054104.1300774-10-willy@infradead.org> (raw)
In-Reply-To: <20210320054104.1300774-1-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>
---
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 5052479febc7..8fc7b04a1438 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1198,18 +1198,26 @@ 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) page_ref_count(&folio->page) + 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);
+ page_ref_inc(&folio->page);
+}
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:[~2021-03-20 5:43 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-20 5:40 [PATCH v5 00/27] Memory Folios Matthew Wilcox (Oracle)
2021-03-20 5:40 ` [PATCH v5 01/27] fs/cachefiles: Remove wait_bit_key layout dependency Matthew Wilcox (Oracle)
2021-03-22 8:06 ` Christoph Hellwig
2021-03-20 5:40 ` [PATCH v5 02/27] mm/writeback: Add wait_on_page_writeback_killable Matthew Wilcox (Oracle)
2021-03-22 8:07 ` Christoph Hellwig
2021-03-20 5:40 ` [PATCH v5 03/27] afs: Use wait_on_page_writeback_killable Matthew Wilcox (Oracle)
2021-03-22 8:08 ` Christoph Hellwig
2021-03-20 5:40 ` [PATCH v5 04/27] mm: Introduce struct folio Matthew Wilcox (Oracle)
2021-03-20 5:40 ` [PATCH v5 05/27] mm: Add folio_pgdat and folio_zone Matthew Wilcox (Oracle)
2021-03-20 5:40 ` [PATCH v5 06/27] mm/vmstat: Add functions to account folio statistics Matthew Wilcox (Oracle)
2021-03-20 5:40 ` [PATCH v5 07/27] mm/debug: Add VM_BUG_ON_FOLIO and VM_WARN_ON_ONCE_FOLIO Matthew Wilcox (Oracle)
2021-03-20 5:40 ` [PATCH v5 08/27] mm: Add put_folio Matthew Wilcox (Oracle)
2021-03-20 5:40 ` Matthew Wilcox (Oracle) [this message]
2021-03-20 5:40 ` [PATCH v5 10/27] mm: Create FolioFlags Matthew Wilcox (Oracle)
2021-03-20 5:40 ` [PATCH v5 11/27] mm: Handle per-folio private data Matthew Wilcox (Oracle)
2021-03-20 5:40 ` [PATCH v5 12/27] mm: Add folio_index, folio_file_page and folio_contains Matthew Wilcox (Oracle)
2021-03-20 5:40 ` [PATCH v5 13/27] mm/util: Add folio_mapping and folio_file_mapping Matthew Wilcox (Oracle)
2021-03-20 5:40 ` [PATCH v5 14/27] mm/memcg: Add folio wrappers for various functions Matthew Wilcox (Oracle)
2021-03-20 5:40 ` [PATCH v5 15/27] mm/filemap: Add unlock_folio Matthew Wilcox (Oracle)
2021-03-20 5:40 ` [PATCH v5 16/27] mm/filemap: Add lock_folio Matthew Wilcox (Oracle)
2021-03-20 5:40 ` [PATCH v5 17/27] mm/filemap: Add lock_folio_killable Matthew Wilcox (Oracle)
2021-03-20 5:40 ` [PATCH v5 18/27] mm/filemap: Add __lock_folio_async Matthew Wilcox (Oracle)
2021-03-20 5:40 ` [PATCH v5 19/27] mm/filemap: Add __lock_folio_or_retry Matthew Wilcox (Oracle)
2021-03-20 5:40 ` [PATCH v5 20/27] mm/filemap: Add wait_on_folio_locked Matthew Wilcox (Oracle)
2021-03-20 5:40 ` [PATCH v5 21/27] mm/filemap: Add end_folio_writeback Matthew Wilcox (Oracle)
2021-03-20 5:40 ` [PATCH v5 22/27] mm/writeback: Add wait_on_folio_writeback Matthew Wilcox (Oracle)
2021-03-20 5:41 ` [PATCH v5 23/27] mm/writeback: Add wait_for_stable_folio Matthew Wilcox (Oracle)
2021-03-20 5:41 ` [PATCH v5 24/27] mm/filemap: Convert wait_on_page_bit to wait_on_folio_bit Matthew Wilcox (Oracle)
2021-03-21 7:10 ` kernel test robot
2021-03-20 5:41 ` [PATCH v5 25/27] mm/filemap: Convert wake_up_page_bit to wake_up_folio_bit Matthew Wilcox (Oracle)
2021-03-20 5:41 ` [PATCH v5 26/27] mm/filemap: Convert page wait queues to be folios Matthew Wilcox (Oracle)
2021-03-20 7:54 ` kernel test robot
2021-03-20 5:41 ` [PATCH v5 27/27] mm/doc: Build kerneldoc for various mm files Matthew Wilcox (Oracle)
2021-03-22 3:25 ` [PATCH v5 00/27] Memory Folios Matthew Wilcox
2021-03-22 9:25 ` [PATCH v5 01/27] fs/cachefiles: Remove wait_bit_key layout dependency David Howells
2021-03-22 9:26 ` [PATCH v5 02/27] mm/writeback: Add wait_on_page_writeback_killable David Howells
2021-03-22 9:27 ` [PATCH v5 03/27] afs: Use wait_on_page_writeback_killable David Howells
2021-03-22 19:41 ` Matthew Wilcox
2021-03-22 17:59 ` [PATCH v5 00/27] Memory Folios Johannes Weiner
2021-03-22 18:47 ` Matthew Wilcox
2021-03-24 0:29 ` Johannes Weiner
2021-03-24 6:24 ` Matthew Wilcox
2021-03-26 17:48 ` Johannes Weiner
2021-03-29 16:58 ` Matthew Wilcox
2021-03-29 17:56 ` Matthew Wilcox
2021-03-30 19:30 ` Johannes Weiner
2021-03-30 21:09 ` Matthew Wilcox
2021-03-31 18:14 ` Johannes Weiner
2021-03-31 18:28 ` Matthew Wilcox
2021-04-01 5:05 ` Al Viro
2021-04-01 12:07 ` Matthew Wilcox
2021-04-01 16:00 ` Johannes Weiner
2021-03-31 14:54 ` Christoph Hellwig
2021-03-23 15:50 ` Christoph Hellwig
2021-03-23 11:29 ` [PATCH v5 03/27] afs: Use wait_on_page_writeback_killable David Howells
2021-03-23 17:50 ` [PATCH v5 00/27] Memory Folios David Howells
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