| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-Id: <20210305041901.2396498-11-willy@infradead.org>
Date: Fri, 5 Mar 2021 04:18:46 +0000
From: "Matthew Wilcox (Oracle)" <willy@...radead.org>
To: linux-mm@...ck.org
Cc: "Matthew Wilcox (Oracle)" <willy@...radead.org>,
linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org
Subject: [PATCH v4 10/25] mm/util: Add folio_mapping and folio_file_mapping
These are the folio equivalent of page_mapping() and page_file_mapping().
Add an out-of-line page_mapping() wrapper around folio_mapping()
in order to prevent the page_folio() call from bloating every caller
of page_mapping(). Adjust page_file_mapping() and page_mapping_file()
to use folios internally.
This ends up saving 102 bytes of text overall. folio_mapping() is
45 bytes shorter than page_mapping() was, but the compiler chooses to
inline folio_mapping() into page_mapping_file(), for a net increase of
69 bytes in the core. This is made up for by a few bytes less in dozens
of nfs functions (which call page_file_mapping()). The small amount of
difference appears to be a slight change in gcc's register allocation
decisions, which allow:
48 8b 56 08 mov 0x8(%rsi),%rdx
48 8d 42 ff lea -0x1(%rdx),%rax
83 e2 01 and $0x1,%edx
48 0f 44 c6 cmove %rsi,%rax
to become:
48 8b 46 08 mov 0x8(%rsi),%rax
48 8d 78 ff lea -0x1(%rax),%rdi
a8 01 test $0x1,%al
48 0f 44 fe cmove %rsi,%rdi
Signed-off-by: Matthew Wilcox (Oracle) <willy@...radead.org>
---
include/linux/mm.h | 14 --------------
include/linux/pagemap.h | 17 +++++++++++++++++
mm/Makefile | 2 +-
mm/folio-compat.c | 13 +++++++++++++
mm/swapfile.c | 6 +++---
mm/util.c | 20 ++++++++++----------
6 files changed, 44 insertions(+), 28 deletions(-)
create mode 100644 mm/folio-compat.c
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 4595955805f8..9199b59ee8da 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1603,19 +1603,6 @@ void page_address_init(void);
extern void *page_rmapping(struct page *page);
extern struct anon_vma *page_anon_vma(struct page *page);
-extern struct address_space *page_mapping(struct page *page);
-
-extern struct address_space *__page_file_mapping(struct page *);
-
-static inline
-struct address_space *page_file_mapping(struct page *page)
-{
- if (unlikely(PageSwapCache(page)))
- return __page_file_mapping(page);
-
- return page->mapping;
-}
-
extern pgoff_t __page_file_index(struct page *page);
/*
@@ -1630,7 +1617,6 @@ static inline pgoff_t page_index(struct page *page)
}
bool page_mapped(struct page *page);
-struct address_space *page_mapping(struct page *page);
struct address_space *page_mapping_file(struct page *page);
/*
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 5094b50f7680..5a2c0764d7c0 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -157,6 +157,23 @@ static inline void filemap_nr_thps_dec(struct address_space *mapping)
void release_pages(struct page **pages, int nr);
+struct address_space *page_mapping(struct page *);
+struct address_space *folio_mapping(struct folio *);
+struct address_space *__folio_file_mapping(struct folio *);
+
+static inline struct address_space *folio_file_mapping(struct folio *folio)
+{
+ if (unlikely(FolioSwapCache(folio)))
+ return __folio_file_mapping(folio);
+
+ return folio->page.mapping;
+}
+
+static inline struct address_space *page_file_mapping(struct page *page)
+{
+ return folio_file_mapping(page_folio(page));
+}
+
/*
* speculatively take a reference to a page.
* If the page is free (_refcount == 0), then _refcount is untouched, and 0
diff --git a/mm/Makefile b/mm/Makefile
index 72227b24a616..ceb0089efd29 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -46,7 +46,7 @@ mmu-$(CONFIG_MMU) += process_vm_access.o
endif
obj-y := filemap.o mempool.o oom_kill.o fadvise.o \
- maccess.o page-writeback.o \
+ maccess.o page-writeback.o folio-compat.o \
readahead.o swap.o truncate.o vmscan.o shmem.o \
util.o mmzone.o vmstat.o backing-dev.o \
mm_init.o percpu.o slab_common.o \
diff --git a/mm/folio-compat.c b/mm/folio-compat.c
new file mode 100644
index 000000000000..5e107aa30a62
--- /dev/null
+++ b/mm/folio-compat.c
@@ -0,0 +1,13 @@
+/*
+ * Compatibility functions which bloat the callers too much to make inline.
+ * All of the callers of these functions should be converted to use folios
+ * eventually.
+ */
+
+#include <linux/pagemap.h>
+
+struct address_space *page_mapping(struct page *page)
+{
+ return folio_mapping(page_folio(page));
+}
+EXPORT_SYMBOL(page_mapping);
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 084a5b9a18e5..b80af7537d9e 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -3535,11 +3535,11 @@ struct swap_info_struct *page_swap_info(struct page *page)
/*
* out-of-line __page_file_ methods to avoid include hell.
*/
-struct address_space *__page_file_mapping(struct page *page)
+struct address_space *__folio_file_mapping(struct folio *folio)
{
- return page_swap_info(page)->swap_file->f_mapping;
+ return page_swap_info(&folio->page)->swap_file->f_mapping;
}
-EXPORT_SYMBOL_GPL(__page_file_mapping);
+EXPORT_SYMBOL_GPL(__folio_file_mapping);
pgoff_t __page_file_index(struct page *page)
{
diff --git a/mm/util.c b/mm/util.c
index 54870226cea6..9ab72cfa4aa1 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -686,39 +686,39 @@ struct anon_vma *page_anon_vma(struct page *page)
return __page_rmapping(page);
}
-struct address_space *page_mapping(struct page *page)
+struct address_space *folio_mapping(struct folio *folio)
{
struct address_space *mapping;
- page = compound_head(page);
-
/* This happens if someone calls flush_dcache_page on slab page */
- if (unlikely(PageSlab(page)))
+ if (unlikely(FolioSlab(folio)))
return NULL;
- if (unlikely(PageSwapCache(page))) {
+ if (unlikely(FolioSwapCache(folio))) {
swp_entry_t entry;
- entry.val = page_private(page);
+ entry.val = folio_private(folio);
return swap_address_space(entry);
}
- mapping = page->mapping;
+ mapping = folio->page.mapping;
if ((unsigned long)mapping & PAGE_MAPPING_ANON)
return NULL;
return (void *)((unsigned long)mapping & ~PAGE_MAPPING_FLAGS);
}
-EXPORT_SYMBOL(page_mapping);
+EXPORT_SYMBOL(folio_mapping);
/*
* For file cache pages, return the address_space, otherwise return NULL
*/
struct address_space *page_mapping_file(struct page *page)
{
- if (unlikely(PageSwapCache(page)))
+ struct folio *folio = page_folio(page);
+
+ if (unlikely(FolioSwapCache(folio)))
return NULL;
- return page_mapping(page);
+ return folio_mapping(folio);
}
/* Slow path of page_mapcount() for compound pages */
--
2.30.0
Powered by blists - more mailing lists