diff mbox series

[RFC,2/3] mm: Return bool from pagebit test functions

Message ID 161796595714.350846.1547688999823745763.stgit@warthog.procyon.org.uk (mailing list archive)
State New, archived
Headers show
Series [RFC,1/3] Make the generic bitops return bool | expand

Commit Message

David Howells April 9, 2021, 10:59 a.m. UTC 
Make functions that test page bits return a bool, not an int.  This means
that the value is definitely 0 or 1 if they're used in arithmetic, rather
than rely on test_bit() and friends to return this (though they probably
should).

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Linus Torvalds <torvalds@linux-foundation.org>
cc: Matthew Wilcox <willy@infradead.org>
cc: Andrew Morton <akpm@linux-foundation.org>
cc: linux-mm@kvack.org
cc: linux-fsdevel@vger.kernel.org
---

 include/linux/page-flags.h |   50 ++++++++++++++++++++++----------------------
 1 file changed, 25 insertions(+), 25 deletions(-)

Comments

Matthew Wilcox (Oracle) April 9, 2021, 11:16 a.m. UTC | #1 
On Fri, Apr 09, 2021 at 11:59:17AM +0100, David Howells wrote:
> Make functions that test page bits return a bool, not an int.  This means
> that the value is definitely 0 or 1 if they're used in arithmetic, rather
> than rely on test_bit() and friends to return this (though they probably
> should).

iirc i looked at doing this as part of the folio work, and it ended up
increasing the size of the kernel.  Did you run bloat-o-meter on the
result of doing this?
David Howells April 9, 2021, noon UTC | #2 
Matthew Wilcox <willy@infradead.org> wrote:

> On Fri, Apr 09, 2021 at 11:59:17AM +0100, David Howells wrote:
> > Make functions that test page bits return a bool, not an int.  This means
> > that the value is definitely 0 or 1 if they're used in arithmetic, rather
> > than rely on test_bit() and friends to return this (though they probably
> > should).
> 
> iirc i looked at doing this as part of the folio work, and it ended up
> increasing the size of the kernel.  Did you run bloat-o-meter on the
> result of doing this?

Hmmm.  With my usual monolithic x86_64 kernel, it makes vmlinux text section
100 bytes larger (19392347 rather than 19392247).  I can look into why.

David
David Howells April 9, 2021, 12:35 p.m. UTC | #3 
Matthew Wilcox <willy@infradead.org> wrote:

> iirc i looked at doing this as part of the folio work, and it ended up
> increasing the size of the kernel.  Did you run bloat-o-meter on the
> result of doing this?

add/remove: 2/2 grow/shrink: 15/16 up/down: 408/-599 (-191)
Function                                     old     new   delta
iomap_write_end_inline                         -     128    +128
try_to_free_swap                              59     179    +120
page_to_index.part                             -      36     +36
page_size                                    432     456     +24
PageTransCompound                            154     175     +21
truncate_inode_pages_range                   791     807     +16
invalidate_inode_pages2_range                504     518     +14
ceph_uninline_data                           969     982     +13
iomap_read_inline_data.isra                  129     139     +10
page_cache_pipe_buf_confirm                   85      93      +8
ceph_writepages_start                       3237    3243      +6
hpage_pincount_available                      94      97      +3
__collapse_huge_page_isolate                 768     771      +3
page_vma_mapped_walk                        1070    1072      +2
PageHuge                                      39      41      +2
collapse_file                               2046    2047      +1
__free_pages_ok                              449     450      +1
wait_on_page_bit_common                      598     597      -1
iomap_page_release                           104     103      -1
change_pte_range                             818     817      -1
pageblock_skip_persistent                     45      42      -3
is_transparent_hugepage                       63      60      -3
nfs_readpage                                 486     482      -4
ext4_readpage_inline                         155     151      -4
release_pages                                640     635      -5
ext4_write_inline_data_end                   286     281      -5
ext4_mb_load_buddy_gfp                       690     684      -6
afs_dir_check                                536     529      -7
page_trans_huge_map_swapcount                374     363     -11
io_uring_mmap                                199     184     -15
io_buffer_account_pin                        276     259     -17
page_to_index                                 50       -     -50
iomap_write_end                              375     306     -69
try_to_free_swap.part                        137       -    -137
PageUptodate                                 716     456    -260
Total: Before=17207139, After=17206948, chg -0.00%
David Howells April 9, 2021, 4:03 p.m. UTC | #4 
David Howells <dhowells@redhat.com> wrote:

> add/remove: 2/2 grow/shrink: 15/16 up/down: 408/-599 (-191)
> Function                                     old     new   delta
> iomap_write_end_inline                         -     128    +128

I can get rid of the iomap_write_end_inline() increase for my config by
marking it __always_inline, thereby getting:

add/remove: 1/2 grow/shrink: 15/15 up/down: 280/-530 (-250)

It seems that the decision whether or not to inline iomap_write_end_inline()
is affected by the switch to bool.

David
diff mbox series

Patch

diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 04a34c08e0a6..4ff7de61b13d 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -188,18 +188,18 @@  static inline struct page *compound_head(struct page *page)
 	return page;
 }
 
-static __always_inline int PageTail(struct page *page)
+static __always_inline bool PageTail(struct page *page)
 {
 	return READ_ONCE(page->compound_head) & 1;
 }
 
-static __always_inline int PageCompound(struct page *page)
+static __always_inline bool PageCompound(struct page *page)
 {
 	return test_bit(PG_head, &page->flags) || PageTail(page);
 }
 
 #define	PAGE_POISON_PATTERN	-1l
-static inline int PagePoisoned(const struct page *page)
+static inline bool PagePoisoned(const struct page *page)
 {
 	return page->flags == PAGE_POISON_PATTERN;
 }
@@ -260,7 +260,7 @@  static inline void page_init_poison(struct page *page, size_t size)
  * Macros to create function definitions for page flags
  */
 #define TESTPAGEFLAG(uname, lname, policy)				\
-static __always_inline int Page##uname(struct page *page)		\
+static __always_inline bool Page##uname(struct page *page)		\
 	{ return test_bit(PG_##lname, &policy(page, 0)->flags); }
 
 #define SETPAGEFLAG(uname, lname, policy)				\
@@ -280,11 +280,11 @@  static __always_inline void __ClearPage##uname(struct page *page)	\
 	{ __clear_bit(PG_##lname, &policy(page, 1)->flags); }
 
 #define TESTSETFLAG(uname, lname, policy)				\
-static __always_inline int TestSetPage##uname(struct page *page)	\
+static __always_inline bool TestSetPage##uname(struct page *page)	\
 	{ return test_and_set_bit(PG_##lname, &policy(page, 1)->flags); }
 
 #define TESTCLEARFLAG(uname, lname, policy)				\
-static __always_inline int TestClearPage##uname(struct page *page)	\
+static __always_inline bool TestClearPage##uname(struct page *page)	\
 	{ return test_and_clear_bit(PG_##lname, &policy(page, 1)->flags); }
 
 #define PAGEFLAG(uname, lname, policy)					\
@@ -302,7 +302,7 @@  static __always_inline int TestClearPage##uname(struct page *page)	\
 	TESTCLEARFLAG(uname, lname, policy)
 
 #define TESTPAGEFLAG_FALSE(uname)					\
-static inline int Page##uname(const struct page *page) { return 0; }
+static inline bool Page##uname(const struct page *page) { return false; }
 
 #define SETPAGEFLAG_NOOP(uname)						\
 static inline void SetPage##uname(struct page *page) {  }
@@ -314,10 +314,10 @@  static inline void ClearPage##uname(struct page *page) {  }
 static inline void __ClearPage##uname(struct page *page) {  }
 
 #define TESTSETFLAG_FALSE(uname)					\
-static inline int TestSetPage##uname(struct page *page) { return 0; }
+static inline bool TestSetPage##uname(struct page *page) { return false; }
 
 #define TESTCLEARFLAG_FALSE(uname)					\
-static inline int TestClearPage##uname(struct page *page) { return 0; }
+static inline bool TestClearPage##uname(struct page *page) { return false; }
 
 #define PAGEFLAG_FALSE(uname) TESTPAGEFLAG_FALSE(uname)			\
 	SETPAGEFLAG_NOOP(uname) CLEARPAGEFLAG_NOOP(uname)
@@ -393,7 +393,7 @@  PAGEFLAG_FALSE(HighMem)
 #endif
 
 #ifdef CONFIG_SWAP
-static __always_inline int PageSwapCache(struct page *page)
+static __always_inline bool PageSwapCache(struct page *page)
 {
 #ifdef CONFIG_THP_SWAP
 	page = compound_head(page);
@@ -473,18 +473,18 @@  __PAGEFLAG(Reported, reported, PF_NO_COMPOUND)
 #define PAGE_MAPPING_KSM	(PAGE_MAPPING_ANON | PAGE_MAPPING_MOVABLE)
 #define PAGE_MAPPING_FLAGS	(PAGE_MAPPING_ANON | PAGE_MAPPING_MOVABLE)
 
-static __always_inline int PageMappingFlags(struct page *page)
+static __always_inline bool PageMappingFlags(struct page *page)
 {
 	return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) != 0;
 }
 
-static __always_inline int PageAnon(struct page *page)
+static __always_inline bool PageAnon(struct page *page)
 {
 	page = compound_head(page);
 	return ((unsigned long)page->mapping & PAGE_MAPPING_ANON) != 0;
 }
 
-static __always_inline int __PageMovable(struct page *page)
+static __always_inline bool __PageMovable(struct page *page)
 {
 	return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) ==
 				PAGE_MAPPING_MOVABLE;
@@ -497,7 +497,7 @@  static __always_inline int __PageMovable(struct page *page)
  * is found in VM_MERGEABLE vmas.  It's a PageAnon page, pointing not to any
  * anon_vma, but to that page's node of the stable tree.
  */
-static __always_inline int PageKsm(struct page *page)
+static __always_inline bool PageKsm(struct page *page)
 {
 	page = compound_head(page);
 	return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) ==
@@ -509,9 +509,9 @@  TESTPAGEFLAG_FALSE(Ksm)
 
 u64 stable_page_flags(struct page *page);
 
-static inline int PageUptodate(struct page *page)
+static inline bool PageUptodate(struct page *page)
 {
-	int ret;
+	bool ret;
 	page = compound_head(page);
 	ret = test_bit(PG_uptodate, &(page)->flags);
 	/*
@@ -607,7 +607,7 @@  TESTPAGEFLAG_FALSE(HeadHuge)
  * hugetlbfs pages, but not normal pages. PageTransHuge() can only be
  * called only in the core VM paths where hugetlbfs pages can't exist.
  */
-static inline int PageTransHuge(struct page *page)
+static inline bool PageTransHuge(struct page *page)
 {
 	VM_BUG_ON_PAGE(PageTail(page), page);
 	return PageHead(page);
@@ -618,7 +618,7 @@  static inline int PageTransHuge(struct page *page)
  * and hugetlbfs pages, so it should only be called when it's known
  * that hugetlbfs pages aren't involved.
  */
-static inline int PageTransCompound(struct page *page)
+static inline bool PageTransCompound(struct page *page)
 {
 	return PageCompound(page);
 }
@@ -644,12 +644,12 @@  static inline int PageTransCompound(struct page *page)
  * mapped in the current process so comparing subpage's _mapcount to
  * compound_mapcount to filter out PTE mapped case.
  */
-static inline int PageTransCompoundMap(struct page *page)
+static inline bool PageTransCompoundMap(struct page *page)
 {
 	struct page *head;
 
 	if (!PageTransCompound(page))
-		return 0;
+		return false;
 
 	if (PageAnon(page))
 		return atomic_read(&page->_mapcount) < 0;
@@ -665,7 +665,7 @@  static inline int PageTransCompoundMap(struct page *page)
  * and hugetlbfs pages, so it should only be called when it's known
  * that hugetlbfs pages aren't involved.
  */
-static inline int PageTransTail(struct page *page)
+static inline bool PageTransTail(struct page *page)
 {
 	return PageTail(page);
 }
@@ -714,13 +714,13 @@  PAGEFLAG_FALSE(DoubleMap)
 #define PageType(page, flag)						\
 	((page->page_type & (PAGE_TYPE_BASE | flag)) == PAGE_TYPE_BASE)
 
-static inline int page_has_type(struct page *page)
+static inline bool page_has_type(struct page *page)
 {
 	return (int)page->page_type < PAGE_MAPCOUNT_RESERVE;
 }
 
 #define PAGE_TYPE_OPS(uname, lname)					\
-static __always_inline int Page##uname(struct page *page)		\
+static __always_inline bool Page##uname(struct page *page)		\
 {									\
 	return PageType(page, PG_##lname);				\
 }									\
@@ -778,7 +778,7 @@  __PAGEFLAG(Isolated, isolated, PF_ANY);
  * If network-based swap is enabled, sl*b must keep track of whether pages
  * were allocated from pfmemalloc reserves.
  */
-static inline int PageSlabPfmemalloc(struct page *page)
+static inline bool PageSlabPfmemalloc(struct page *page)
 {
 	VM_BUG_ON_PAGE(!PageSlab(page), page);
 	return PageActive(page);
@@ -839,7 +839,7 @@  static inline void ClearPageSlabPfmemalloc(struct page *page)
  * Determine if a page has private stuff, indicating that release routines
  * should be invoked upon it.
  */
-static inline int page_has_private(struct page *page)
+static inline bool page_has_private(struct page *page)
 {
 	return !!(page->flags & PAGE_FLAGS_PRIVATE);
 }