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
Subject: [PATCH v5 11/27] mm: Handle per-folio private data
Date: Sat, 20 Mar 2021 05:40:48 +0000 [thread overview]
Message-ID: <20210320054104.1300774-12-willy@infradead.org> (raw)
In-Reply-To: <20210320054104.1300774-1-willy@infradead.org>
Add folio_private() and set_folio_private() which mirror page_private()
and set_page_private() -- ie folio private data is the same as page
private data. The only difference is that these return a void *
instead of an unsigned long, which matches the majority of users.
Turn attach_page_private() into attach_folio_private() and reimplement
attach_page_private() as a wrapper. No filesystem which uses page private
data currently supports compound pages, so we're free to define the rules.
attach_page_private() may only be called on a head page; if you want
to add private data to a tail page, you can call set_page_private()
directly (and shouldn't increment the page refcount! That should be
done when adding private data to the head page / folio).
This saves 597 bytes of text with the distro-derived config that I'm
testing due to removing the calls to compound_head() in get_page()
& put_page().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
include/linux/mm_types.h | 16 ++++++++++++++
include/linux/pagemap.h | 48 ++++++++++++++++++++++++----------------
2 files changed, 45 insertions(+), 19 deletions(-)
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 4fc0b230d3ea..90086f93e9de 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -278,6 +278,12 @@ static inline atomic_t *compound_pincount_ptr(struct page *page)
#define PAGE_FRAG_CACHE_MAX_SIZE __ALIGN_MASK(32768, ~PAGE_MASK)
#define PAGE_FRAG_CACHE_MAX_ORDER get_order(PAGE_FRAG_CACHE_MAX_SIZE)
+/*
+ * page_private can be used on tail pages. However, PagePrivate is only
+ * checked by the VM on the head page. So page_private on the tail pages
+ * should be used for data that's ancillary to the head page (eg attaching
+ * buffer heads to tail pages after attaching buffer heads to the head page)
+ */
#define page_private(page) ((page)->private)
static inline void set_page_private(struct page *page, unsigned long private)
@@ -285,6 +291,16 @@ static inline void set_page_private(struct page *page, unsigned long private)
page->private = private;
}
+static inline void *folio_private(struct folio *folio)
+{
+ return (void *)folio->page.private;
+}
+
+static inline void set_folio_private(struct folio *folio, void *v)
+{
+ folio->page.private = (unsigned long)v;
+}
+
struct page_frag_cache {
void * va;
#if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 8c844ba67785..6676210addf6 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -260,42 +260,52 @@ static inline int page_cache_add_speculative(struct page *page, int count)
}
/**
- * attach_page_private - Attach private data to a page.
- * @page: Page to attach data to.
- * @data: Data to attach to page.
+ * attach_folio_private - Attach private data to a folio.
+ * @folio: Folio to attach data to.
+ * @data: Data to attach to folio.
*
- * Attaching private data to a page increments the page's reference count.
- * The data must be detached before the page will be freed.
+ * Attaching private data to a folio increments the page's reference count.
+ * The data must be detached before the folio will be freed.
*/
-static inline void attach_page_private(struct page *page, void *data)
+static inline void attach_folio_private(struct folio *folio, void *data)
{
- get_page(page);
- set_page_private(page, (unsigned long)data);
- SetPagePrivate(page);
+ get_folio(folio);
+ set_folio_private(folio, data);
+ SetFolioPrivate(folio);
}
/**
- * detach_page_private - Detach private data from a page.
- * @page: Page to detach data from.
+ * detach_folio_private - Detach private data from a folio.
+ * @folio: Folio to detach data from.
*
- * Removes the data that was previously attached to the page and decrements
+ * Removes the data that was previously attached to the folio and decrements
* the refcount on the page.
*
- * Return: Data that was attached to the page.
+ * Return: Data that was attached to the folio.
*/
-static inline void *detach_page_private(struct page *page)
+static inline void *detach_folio_private(struct folio *folio)
{
- void *data = (void *)page_private(page);
+ void *data = folio_private(folio);
- if (!PagePrivate(page))
+ if (!FolioPrivate(folio))
return NULL;
- ClearPagePrivate(page);
- set_page_private(page, 0);
- put_page(page);
+ ClearFolioPrivate(folio);
+ set_folio_private(folio, NULL);
+ put_folio(folio);
return data;
}
+static inline void attach_page_private(struct page *page, void *data)
+{
+ attach_folio_private(page_folio(page), data);
+}
+
+static inline void *detach_page_private(struct page *page)
+{
+ return detach_folio_private(page_folio(page));
+}
+
#ifdef CONFIG_NUMA
extern struct page *__page_cache_alloc(gfp_t gfp);
#else
--
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 ` [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 ` Matthew Wilcox (Oracle) [this message]
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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