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 08/27] mm: Add put_folio
Date: Sat, 20 Mar 2021 05:40:45 +0000 [thread overview]
Message-ID: <20210320054104.1300774-9-willy@infradead.org> (raw)
In-Reply-To: <20210320054104.1300774-1-willy@infradead.org>
If we know we have a folio, we can call put_folio() instead of put_page()
and save the overhead of calling compound_head(). Also skips the
devmap checks.
This commit looks like it should be a no-op, but actually saves 1714 bytes
of text with the distro-derived config that I'm testing. Some functions
grow a little while others shrink. I presume the compiler is making
different inlining decisions.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
---
include/linux/mm.h | 28 +++++++++++++++++++++++-----
1 file changed, 23 insertions(+), 5 deletions(-)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index e176e9c9990f..5052479febc7 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1226,9 +1226,28 @@ static inline __must_check bool try_get_page(struct page *page)
return true;
}
+/**
+ * put_folio - Decrement the reference count on a folio.
+ * @folio: The folio.
+ *
+ * If the folio's reference count reaches zero, the memory will be
+ * released back to the page allocator and may be used by another
+ * allocation immediately. Do not access the memory or the struct folio
+ * after calling put_folio() unless you can be sure that it wasn't the
+ * last reference.
+ *
+ * Context: May be called in process or interrupt context, but not in NMI
+ * context. May be called while holding a spinlock.
+ */
+static inline void put_folio(struct folio *folio)
+{
+ if (put_page_testzero(&folio->page))
+ __put_page(&folio->page);
+}
+
static inline void put_page(struct page *page)
{
- page = compound_head(page);
+ struct folio *folio = page_folio(page);
/*
* For devmap managed pages we need to catch refcount transition from
@@ -1236,13 +1255,12 @@ static inline void put_page(struct page *page)
* need to inform the device driver through callback. See
* include/linux/memremap.h and HMM for details.
*/
- if (page_is_devmap_managed(page)) {
- put_devmap_managed_page(page);
+ if (page_is_devmap_managed(&folio->page)) {
+ put_devmap_managed_page(&folio->page);
return;
}
- if (put_page_testzero(page))
- __put_page(page);
+ put_folio(folio);
}
/*
--
2.30.2
next prev parent reply other threads:[~2021-03-20 5:42 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 ` Matthew Wilcox (Oracle) [this message]
2021-03-20 5:40 ` [PATCH v5 09/27] mm: Add get_folio Matthew Wilcox (Oracle)
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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