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mm: Add folio flag manipulation functions

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These new functions are the folio analogues of the various PageFlags
functions.  If CONFIG_DEBUG_VM_PGFLAGS is enabled, we check the folio
is not a tail page at every invocation.  This will also catch the
PagePoisoned case as a poisoned page has every bit set, which would
include PageTail.

This saves 1684 bytes of text with the distro-derived config that
I'm testing due to removing a double call to compound_head() in
PageSwapCache().

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Jeff Layton <jlayton@kernel.org>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
This commit is contained in:
Matthew Wilcox (Oracle) 2020-12-07 15:42:09 -05:00
parent 020853b6f5
commit d389a4a811
1 changed files with 160 additions and 67 deletions
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227
include/linux/page-flags.h
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@ -143,6 +143,8 @@ enum pageflags {
#endif #endif
__NR_PAGEFLAGS, __NR_PAGEFLAGS,
PG_readahead = PG_reclaim,
/* Filesystems */ /* Filesystems */
PG_checked = PG_owner_priv_1, PG_checked = PG_owner_priv_1,
@ -245,6 +247,15 @@ static inline void page_init_poison(struct page *page, size_t size)
} }
#endif #endif
static unsigned long *folio_flags(struct folio *folio, unsigned n)
{
struct page *page = &folio->page;
VM_BUG_ON_PGFLAGS(PageTail(page), page);
VM_BUG_ON_PGFLAGS(n > 0 && !test_bit(PG_head, &page->flags), page);
return &page[n].flags;
}
/* /*
* Page flags policies wrt compound pages * Page flags policies wrt compound pages
* *
@ -289,36 +300,64 @@ static inline void page_init_poison(struct page *page, size_t size)
VM_BUG_ON_PGFLAGS(!PageHead(page), page); \ VM_BUG_ON_PGFLAGS(!PageHead(page), page); \
PF_POISONED_CHECK(&page[1]); }) PF_POISONED_CHECK(&page[1]); })
/* Which page is the flag stored in */
#define FOLIO_PF_ANY 0
#define FOLIO_PF_HEAD 0
#define FOLIO_PF_ONLY_HEAD 0
#define FOLIO_PF_NO_TAIL 0
#define FOLIO_PF_NO_COMPOUND 0
#define FOLIO_PF_SECOND 1
/* /*
* Macros to create function definitions for page flags * Macros to create function definitions for page flags
*/ */
#define TESTPAGEFLAG(uname, lname, policy) \ #define TESTPAGEFLAG(uname, lname, policy) \
static __always_inline bool folio_test_##lname(struct folio *folio) \
{ return test_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); } \
static __always_inline int Page##uname(struct page *page) \ static __always_inline int Page##uname(struct page *page) \
{ return test_bit(PG_##lname, &policy(page, 0)->flags); } { return test_bit(PG_##lname, &policy(page, 0)->flags); }
#define SETPAGEFLAG(uname, lname, policy) \ #define SETPAGEFLAG(uname, lname, policy) \
static __always_inline \
void folio_set_##lname(struct folio *folio) \
{ set_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); } \
static __always_inline void SetPage##uname(struct page *page) \ static __always_inline void SetPage##uname(struct page *page) \
{ set_bit(PG_##lname, &policy(page, 1)->flags); } { set_bit(PG_##lname, &policy(page, 1)->flags); }
#define CLEARPAGEFLAG(uname, lname, policy) \ #define CLEARPAGEFLAG(uname, lname, policy) \
static __always_inline \
void folio_clear_##lname(struct folio *folio) \
{ clear_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); } \
static __always_inline void ClearPage##uname(struct page *page) \ static __always_inline void ClearPage##uname(struct page *page) \
{ clear_bit(PG_##lname, &policy(page, 1)->flags); } { clear_bit(PG_##lname, &policy(page, 1)->flags); }
#define __SETPAGEFLAG(uname, lname, policy) \ #define __SETPAGEFLAG(uname, lname, policy) \
static __always_inline \
void __folio_set_##lname(struct folio *folio) \
{ __set_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); } \
static __always_inline void __SetPage##uname(struct page *page) \ static __always_inline void __SetPage##uname(struct page *page) \
{ __set_bit(PG_##lname, &policy(page, 1)->flags); } { __set_bit(PG_##lname, &policy(page, 1)->flags); }
#define __CLEARPAGEFLAG(uname, lname, policy) \ #define __CLEARPAGEFLAG(uname, lname, policy) \
static __always_inline \
void __folio_clear_##lname(struct folio *folio) \
{ __clear_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); } \
static __always_inline void __ClearPage##uname(struct page *page) \ static __always_inline void __ClearPage##uname(struct page *page) \
{ __clear_bit(PG_##lname, &policy(page, 1)->flags); } { __clear_bit(PG_##lname, &policy(page, 1)->flags); }
#define TESTSETFLAG(uname, lname, policy) \ #define TESTSETFLAG(uname, lname, policy) \
static __always_inline \
bool folio_test_set_##lname(struct folio *folio) \
{ return test_and_set_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); } \
static __always_inline int TestSetPage##uname(struct page *page) \ static __always_inline int TestSetPage##uname(struct page *page) \
{ return test_and_set_bit(PG_##lname, &policy(page, 1)->flags); } { return test_and_set_bit(PG_##lname, &policy(page, 1)->flags); }
#define TESTCLEARFLAG(uname, lname, policy) \ #define TESTCLEARFLAG(uname, lname, policy) \
static __always_inline \
bool folio_test_clear_##lname(struct folio *folio) \
{ return test_and_clear_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); } \
static __always_inline int TestClearPage##uname(struct page *page) \ static __always_inline int TestClearPage##uname(struct page *page) \
{ return test_and_clear_bit(PG_##lname, &policy(page, 1)->flags); } { return test_and_clear_bit(PG_##lname, &policy(page, 1)->flags); }
#define PAGEFLAG(uname, lname, policy) \ #define PAGEFLAG(uname, lname, policy) \
TESTPAGEFLAG(uname, lname, policy) \ TESTPAGEFLAG(uname, lname, policy) \
@ -334,29 +373,37 @@ static __always_inline int TestClearPage##uname(struct page *page) \
TESTSETFLAG(uname, lname, policy) \ TESTSETFLAG(uname, lname, policy) \
TESTCLEARFLAG(uname, lname, policy) TESTCLEARFLAG(uname, lname, policy)
#define TESTPAGEFLAG_FALSE(uname) \ #define TESTPAGEFLAG_FALSE(uname, lname) \
static inline bool folio_test_##lname(const struct folio *folio) { return 0; } \
static inline int Page##uname(const struct page *page) { return 0; } static inline int Page##uname(const struct page *page) { return 0; }
#define SETPAGEFLAG_NOOP(uname) \ #define SETPAGEFLAG_NOOP(uname, lname) \
static inline void folio_set_##lname(struct folio *folio) { } \
static inline void SetPage##uname(struct page *page) { } static inline void SetPage##uname(struct page *page) { }
#define CLEARPAGEFLAG_NOOP(uname) \ #define CLEARPAGEFLAG_NOOP(uname, lname) \
static inline void folio_clear_##lname(struct folio *folio) { } \
static inline void ClearPage##uname(struct page *page) { } static inline void ClearPage##uname(struct page *page) { }
#define __CLEARPAGEFLAG_NOOP(uname) \ #define __CLEARPAGEFLAG_NOOP(uname, lname) \
static inline void __folio_clear_##lname(struct folio *folio) { } \
static inline void __ClearPage##uname(struct page *page) { } static inline void __ClearPage##uname(struct page *page) { }
#define TESTSETFLAG_FALSE(uname) \ #define TESTSETFLAG_FALSE(uname, lname) \
static inline bool folio_test_set_##lname(struct folio *folio) \
{ return 0; } \
static inline int TestSetPage##uname(struct page *page) { return 0; } static inline int TestSetPage##uname(struct page *page) { return 0; }
#define TESTCLEARFLAG_FALSE(uname) \ #define TESTCLEARFLAG_FALSE(uname, lname) \
static inline bool folio_test_clear_##lname(struct folio *folio) \
{ return 0; } \
static inline int TestClearPage##uname(struct page *page) { return 0; } static inline int TestClearPage##uname(struct page *page) { return 0; }
#define PAGEFLAG_FALSE(uname) TESTPAGEFLAG_FALSE(uname) \ #define PAGEFLAG_FALSE(uname, lname) TESTPAGEFLAG_FALSE(uname, lname) \
SETPAGEFLAG_NOOP(uname) CLEARPAGEFLAG_NOOP(uname) SETPAGEFLAG_NOOP(uname, lname) CLEARPAGEFLAG_NOOP(uname, lname)
#define TESTSCFLAG_FALSE(uname) \ #define TESTSCFLAG_FALSE(uname, lname) \
TESTSETFLAG_FALSE(uname) TESTCLEARFLAG_FALSE(uname) TESTSETFLAG_FALSE(uname, lname) TESTCLEARFLAG_FALSE(uname, lname)
__PAGEFLAG(Locked, locked, PF_NO_TAIL) __PAGEFLAG(Locked, locked, PF_NO_TAIL)
PAGEFLAG(Waiters, waiters, PF_ONLY_HEAD) __CLEARPAGEFLAG(Waiters, waiters, PF_ONLY_HEAD) PAGEFLAG(Waiters, waiters, PF_ONLY_HEAD) __CLEARPAGEFLAG(Waiters, waiters, PF_ONLY_HEAD)
@ -412,8 +459,8 @@ PAGEFLAG(MappedToDisk, mappedtodisk, PF_NO_TAIL)
/* PG_readahead is only used for reads; PG_reclaim is only for writes */ /* PG_readahead is only used for reads; PG_reclaim is only for writes */
PAGEFLAG(Reclaim, reclaim, PF_NO_TAIL) PAGEFLAG(Reclaim, reclaim, PF_NO_TAIL)
TESTCLEARFLAG(Reclaim, reclaim, PF_NO_TAIL) TESTCLEARFLAG(Reclaim, reclaim, PF_NO_TAIL)
PAGEFLAG(Readahead, reclaim, PF_NO_COMPOUND) PAGEFLAG(Readahead, readahead, PF_NO_COMPOUND)
TESTCLEARFLAG(Readahead, reclaim, PF_NO_COMPOUND) TESTCLEARFLAG(Readahead, readahead, PF_NO_COMPOUND)
#ifdef CONFIG_HIGHMEM #ifdef CONFIG_HIGHMEM
/* /*
@ -422,22 +469,25 @@ PAGEFLAG(Readahead, reclaim, PF_NO_COMPOUND)
*/ */
#define PageHighMem(__p) is_highmem_idx(page_zonenum(__p)) #define PageHighMem(__p) is_highmem_idx(page_zonenum(__p))
#else #else
PAGEFLAG_FALSE(HighMem) PAGEFLAG_FALSE(HighMem, highmem)
#endif #endif
#ifdef CONFIG_SWAP #ifdef CONFIG_SWAP
static __always_inline int PageSwapCache(struct page *page) static __always_inline bool folio_test_swapcache(struct folio *folio)
{ {
#ifdef CONFIG_THP_SWAP return folio_test_swapbacked(folio) &&
page = compound_head(page); test_bit(PG_swapcache, folio_flags(folio, 0));
#endif
return PageSwapBacked(page) && test_bit(PG_swapcache, &page->flags);
} }
static __always_inline bool PageSwapCache(struct page *page)
{
return folio_test_swapcache(page_folio(page));
}
SETPAGEFLAG(SwapCache, swapcache, PF_NO_TAIL) SETPAGEFLAG(SwapCache, swapcache, PF_NO_TAIL)
CLEARPAGEFLAG(SwapCache, swapcache, PF_NO_TAIL) CLEARPAGEFLAG(SwapCache, swapcache, PF_NO_TAIL)
#else #else
PAGEFLAG_FALSE(SwapCache) PAGEFLAG_FALSE(SwapCache, swapcache)
#endif #endif
PAGEFLAG(Unevictable, unevictable, PF_HEAD) PAGEFLAG(Unevictable, unevictable, PF_HEAD)
@ -449,14 +499,14 @@ PAGEFLAG(Mlocked, mlocked, PF_NO_TAIL)
__CLEARPAGEFLAG(Mlocked, mlocked, PF_NO_TAIL) __CLEARPAGEFLAG(Mlocked, mlocked, PF_NO_TAIL)
TESTSCFLAG(Mlocked, mlocked, PF_NO_TAIL) TESTSCFLAG(Mlocked, mlocked, PF_NO_TAIL)
#else #else
PAGEFLAG_FALSE(Mlocked) __CLEARPAGEFLAG_NOOP(Mlocked) PAGEFLAG_FALSE(Mlocked, mlocked) __CLEARPAGEFLAG_NOOP(Mlocked, mlocked)
TESTSCFLAG_FALSE(Mlocked) TESTSCFLAG_FALSE(Mlocked, mlocked)
#endif #endif
#ifdef CONFIG_ARCH_USES_PG_UNCACHED #ifdef CONFIG_ARCH_USES_PG_UNCACHED
PAGEFLAG(Uncached, uncached, PF_NO_COMPOUND) PAGEFLAG(Uncached, uncached, PF_NO_COMPOUND)
#else #else
PAGEFLAG_FALSE(Uncached) PAGEFLAG_FALSE(Uncached, uncached)
#endif #endif
#ifdef CONFIG_MEMORY_FAILURE #ifdef CONFIG_MEMORY_FAILURE
@ -465,7 +515,7 @@ TESTSCFLAG(HWPoison, hwpoison, PF_ANY)
#define __PG_HWPOISON (1UL << PG_hwpoison) #define __PG_HWPOISON (1UL << PG_hwpoison)
extern bool take_page_off_buddy(struct page *page); extern bool take_page_off_buddy(struct page *page);
#else #else
PAGEFLAG_FALSE(HWPoison) PAGEFLAG_FALSE(HWPoison, hwpoison)
#define __PG_HWPOISON 0 #define __PG_HWPOISON 0
#endif #endif
@ -479,7 +529,7 @@ PAGEFLAG(Idle, idle, PF_ANY)
#ifdef CONFIG_KASAN_HW_TAGS #ifdef CONFIG_KASAN_HW_TAGS
PAGEFLAG(SkipKASanPoison, skip_kasan_poison, PF_HEAD) PAGEFLAG(SkipKASanPoison, skip_kasan_poison, PF_HEAD)
#else #else
PAGEFLAG_FALSE(SkipKASanPoison) PAGEFLAG_FALSE(SkipKASanPoison, skip_kasan_poison)
#endif #endif
/* /*
@ -517,10 +567,14 @@ static __always_inline int PageMappingFlags(struct page *page)
return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) != 0; return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) != 0;
} }
static __always_inline int PageAnon(struct page *page) static __always_inline bool folio_test_anon(struct folio *folio)
{ {
page = compound_head(page); return ((unsigned long)folio->mapping & PAGE_MAPPING_ANON) != 0;
return ((unsigned long)page->mapping & PAGE_MAPPING_ANON) != 0; }
static __always_inline bool PageAnon(struct page *page)
{
return folio_test_anon(page_folio(page));
} }
static __always_inline int __PageMovable(struct page *page) static __always_inline int __PageMovable(struct page *page)
@ -536,30 +590,32 @@ static __always_inline int __PageMovable(struct page *page)
* is found in VM_MERGEABLE vmas. It's a PageAnon page, pointing not to any * 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. * anon_vma, but to that page's node of the stable tree.
*/ */
static __always_inline int PageKsm(struct page *page) static __always_inline bool folio_test_ksm(struct folio *folio)
{ {
page = compound_head(page); return ((unsigned long)folio->mapping & PAGE_MAPPING_FLAGS) ==
return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) ==
PAGE_MAPPING_KSM; PAGE_MAPPING_KSM;
} }
static __always_inline bool PageKsm(struct page *page)
{
return folio_test_ksm(page_folio(page));
}
#else #else
TESTPAGEFLAG_FALSE(Ksm) TESTPAGEFLAG_FALSE(Ksm, ksm)
#endif #endif
u64 stable_page_flags(struct page *page); u64 stable_page_flags(struct page *page);
static inline int PageUptodate(struct page *page) static inline bool folio_test_uptodate(struct folio *folio)
{ {
int ret; bool ret = test_bit(PG_uptodate, folio_flags(folio, 0));
page = compound_head(page);
ret = test_bit(PG_uptodate, &(page)->flags);
/* /*
* Must ensure that the data we read out of the page is loaded * Must ensure that the data we read out of the folio is loaded
* _after_ we've loaded page->flags to check for PageUptodate. * _after_ we've loaded folio->flags to check the uptodate bit.
* We can skip the barrier if the page is not uptodate, because * We can skip the barrier if the folio is not uptodate, because
* we wouldn't be reading anything from it. * we wouldn't be reading anything from it.
* *
* See SetPageUptodate() for the other side of the story. * See folio_mark_uptodate() for the other side of the story.
*/ */
if (ret) if (ret)
smp_rmb(); smp_rmb();
@ -567,23 +623,36 @@ static inline int PageUptodate(struct page *page)
return ret; return ret;
} }
static inline int PageUptodate(struct page *page)
{
return folio_test_uptodate(page_folio(page));
}
static __always_inline void __folio_mark_uptodate(struct folio *folio)
{
smp_wmb();
__set_bit(PG_uptodate, folio_flags(folio, 0));
}
static __always_inline void folio_mark_uptodate(struct folio *folio)
{
/*
* Memory barrier must be issued before setting the PG_uptodate bit,
* so that all previous stores issued in order to bring the folio
* uptodate are actually visible before folio_test_uptodate becomes true.
*/
smp_wmb();
set_bit(PG_uptodate, folio_flags(folio, 0));
}
static __always_inline void __SetPageUptodate(struct page *page) static __always_inline void __SetPageUptodate(struct page *page)
{ {
VM_BUG_ON_PAGE(PageTail(page), page); __folio_mark_uptodate((struct folio *)page);
smp_wmb();
__set_bit(PG_uptodate, &page->flags);
} }
static __always_inline void SetPageUptodate(struct page *page) static __always_inline void SetPageUptodate(struct page *page)
{ {
VM_BUG_ON_PAGE(PageTail(page), page); folio_mark_uptodate((struct folio *)page);
/*
* Memory barrier must be issued before setting the PG_uptodate bit,
* so that all previous stores issued in order to bring the page
* uptodate are actually visible before PageUptodate becomes true.
*/
smp_wmb();
set_bit(PG_uptodate, &page->flags);
} }
CLEARPAGEFLAG(Uptodate, uptodate, PF_NO_TAIL) CLEARPAGEFLAG(Uptodate, uptodate, PF_NO_TAIL)
@ -608,6 +677,17 @@ static inline void set_page_writeback_keepwrite(struct page *page)
__PAGEFLAG(Head, head, PF_ANY) CLEARPAGEFLAG(Head, head, PF_ANY) __PAGEFLAG(Head, head, PF_ANY) CLEARPAGEFLAG(Head, head, PF_ANY)
/* Whether there are one or multiple pages in a folio */
static inline bool folio_test_single(struct folio *folio)
{
return !folio_test_head(folio);
}
static inline bool folio_test_multi(struct folio *folio)
{
return folio_test_head(folio);
}
static __always_inline void set_compound_head(struct page *page, struct page *head) static __always_inline void set_compound_head(struct page *page, struct page *head)
{ {
WRITE_ONCE(page->compound_head, (unsigned long)head + 1); WRITE_ONCE(page->compound_head, (unsigned long)head + 1);
@ -631,12 +711,15 @@ static inline void ClearPageCompound(struct page *page)
#ifdef CONFIG_HUGETLB_PAGE #ifdef CONFIG_HUGETLB_PAGE
int PageHuge(struct page *page); int PageHuge(struct page *page);
int PageHeadHuge(struct page *page); int PageHeadHuge(struct page *page);
static inline bool folio_test_hugetlb(struct folio *folio)
{
return PageHeadHuge(&folio->page);
}
#else #else
TESTPAGEFLAG_FALSE(Huge) TESTPAGEFLAG_FALSE(Huge, hugetlb)
TESTPAGEFLAG_FALSE(HeadHuge) TESTPAGEFLAG_FALSE(HeadHuge, headhuge)
#endif #endif
#ifdef CONFIG_TRANSPARENT_HUGEPAGE #ifdef CONFIG_TRANSPARENT_HUGEPAGE
/* /*
* PageHuge() only returns true for hugetlbfs pages, but not for * PageHuge() only returns true for hugetlbfs pages, but not for
@ -652,6 +735,11 @@ static inline int PageTransHuge(struct page *page)
return PageHead(page); return PageHead(page);
} }
static inline bool folio_test_transhuge(struct folio *folio)
{
return folio_test_head(folio);
}
/* /*
* PageTransCompound returns true for both transparent huge pages * PageTransCompound returns true for both transparent huge pages
* and hugetlbfs pages, so it should only be called when it's known * and hugetlbfs pages, so it should only be called when it's known
@ -688,12 +776,12 @@ static inline int PageTransTail(struct page *page)
PAGEFLAG(DoubleMap, double_map, PF_SECOND) PAGEFLAG(DoubleMap, double_map, PF_SECOND)
TESTSCFLAG(DoubleMap, double_map, PF_SECOND) TESTSCFLAG(DoubleMap, double_map, PF_SECOND)
#else #else
TESTPAGEFLAG_FALSE(TransHuge) TESTPAGEFLAG_FALSE(TransHuge, transhuge)
TESTPAGEFLAG_FALSE(TransCompound) TESTPAGEFLAG_FALSE(TransCompound, transcompound)
TESTPAGEFLAG_FALSE(TransCompoundMap) TESTPAGEFLAG_FALSE(TransCompoundMap, transcompoundmap)
TESTPAGEFLAG_FALSE(TransTail) TESTPAGEFLAG_FALSE(TransTail, transtail)
PAGEFLAG_FALSE(DoubleMap) PAGEFLAG_FALSE(DoubleMap, double_map)
TESTSCFLAG_FALSE(DoubleMap) TESTSCFLAG_FALSE(DoubleMap, double_map)
#endif #endif
/* /*
@ -877,6 +965,11 @@ static inline int page_has_private(struct page *page)
return !!(page->flags & PAGE_FLAGS_PRIVATE); return !!(page->flags & PAGE_FLAGS_PRIVATE);
} }
static inline bool folio_has_private(struct folio *folio)
{
return page_has_private(&folio->page);
}
#undef PF_ANY #undef PF_ANY
#undef PF_HEAD #undef PF_HEAD
#undef PF_ONLY_HEAD #undef PF_ONLY_HEAD