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,
Christoph Hellwig <hch@lst.de>, Jeff Layton <jlayton@kernel.org>
Subject: [PATCH v7 10/28] mm: Handle per-folio private data
Date: Fri, 9 Apr 2021 19:50:47 +0100 [thread overview]
Message-ID: <20210409185105.188284-11-willy@infradead.org> (raw)
In-Reply-To: <20210409185105.188284-1-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>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Jeff Layton <jlayton@kernel.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 d65050851037..1210a8e41fad 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -322,6 +322,12 @@ 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)
@@ -329,6 +335,16 @@ 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->private;
+}
+
+static inline void set_folio_private(struct folio *folio, void *v)
+{
+ folio->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 350e1c9726f2..f2fd0b811c1b 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:[~2021-04-09 18:59 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 ` [PATCH v7 08/28] mm: Add get_folio Matthew Wilcox (Oracle)
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 ` Matthew Wilcox (Oracle) [this message]
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)
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