Stored in the first tail page's flags, this flag replaces the destructor.
That removes the last of the destructors, so remove all references to
folio_dtor and compound_dtor.
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
---
Documentation/admin-guide/kdump/vmcoreinfo.rst | 4 ++--
include/linux/mm.h | 13 -------------
include/linux/mm_types.h | 2 --
include/linux/page-flags.h | 7 ++++++-
kernel/crash_core.c | 1 -
mm/huge_memory.c | 4 ++--
mm/internal.h | 1 -
mm/page_alloc.c | 7 +------
8 files changed, 11 insertions(+), 28 deletions(-)
diff --git a/Documentation/admin-guide/kdump/vmcoreinfo.rst b/Documentation/admin-guide/kdump/vmcoreinfo.rst
index baa1c355741d..3bd38ac0e7de 100644
--- a/Documentation/admin-guide/kdump/vmcoreinfo.rst
+++ b/Documentation/admin-guide/kdump/vmcoreinfo.rst
@@ -141,8 +141,8 @@ nodemask_t
The size of a nodemask_t type. Used to compute the number of online
nodes.
-(page, flags|_refcount|mapping|lru|_mapcount|private|compound_dtor|compound_order|compound_head)
--------------------------------------------------------------------------------------------------
+(page, flags|_refcount|mapping|lru|_mapcount|private|compound_order|compound_head)
+----------------------------------------------------------------------------------
User-space tools compute their values based on the offset of these
variables. The variables are used when excluding unnecessary pages.
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 642f5fe5860e..cf0ae8c51d7f 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1267,19 +1267,6 @@ void folio_copy(struct folio *dst, struct folio *src);
unsigned long nr_free_buffer_pages(void);
-enum compound_dtor_id {
- COMPOUND_PAGE_DTOR,
- TRANSHUGE_PAGE_DTOR,
- NR_COMPOUND_DTORS,
-};
-
-static inline void folio_set_compound_dtor(struct folio *folio,
- enum compound_dtor_id compound_dtor)
-{
- VM_BUG_ON_FOLIO(compound_dtor >= NR_COMPOUND_DTORS, folio);
- folio->_folio_dtor = compound_dtor;
-}
-
void destroy_large_folio(struct folio *folio);
/* Returns the number of bytes in this potentially compound page. */
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index da538ff68953..d45a2b8041e0 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -282,7 +282,6 @@ static inline struct page *encoded_page_ptr(struct encoded_page *page)
* @_refcount: Do not access this member directly. Use folio_ref_count()
* to find how many references there are to this folio.
* @memcg_data: Memory Control Group data.
- * @_folio_dtor: Which destructor to use for this folio.
* @_folio_order: Do not use directly, call folio_order().
* @_entire_mapcount: Do not use directly, call folio_entire_mapcount().
* @_nr_pages_mapped: Do not use directly, call folio_mapcount().
@@ -336,7 +335,6 @@ struct folio {
unsigned long _flags_1;
unsigned long _head_1;
/* public: */
- unsigned char _folio_dtor;
unsigned char _folio_order;
atomic_t _entire_mapcount;
atomic_t _nr_pages_mapped;
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index aeecf0cf1456..732d13c708e7 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -190,6 +190,7 @@ enum pageflags {
/* At least one page in this folio has the hwpoison flag set */
PG_has_hwpoisoned = PG_error,
PG_hugetlb = PG_active,
+ PG_large_rmappable = PG_workingset, /* anon or file-backed */
};
#define PAGEFLAGS_MASK ((1UL << NR_PAGEFLAGS) - 1)
@@ -806,6 +807,9 @@ static inline void ClearPageCompound(struct page *page)
BUG_ON(!PageHead(page));
ClearPageHead(page);
}
+PAGEFLAG(LargeRmappable, large_rmappable, PF_SECOND)
+#else
+TESTPAGEFLAG_FALSE(LargeRmappable, large_rmappable)
#endif
#define PG_head_mask ((1UL << PG_head))
@@ -1061,7 +1065,8 @@ static __always_inline void __ClearPageAnonExclusive(struct page *page)
* the CHECK_AT_FREE flags above, so need to be cleared.
*/
#define PAGE_FLAGS_SECOND \
- (1UL << PG_has_hwpoisoned | 1UL << PG_hugetlb)
+ (1UL << PG_has_hwpoisoned | 1UL << PG_hugetlb | \
+ 1UL << PG_large_rmappable)
#define PAGE_FLAGS_PRIVATE \
(1UL << PG_private | 1UL << PG_private_2)
diff --git a/kernel/crash_core.c b/kernel/crash_core.c
index dd5f87047d06..934dd86e19f5 100644
--- a/kernel/crash_core.c
+++ b/kernel/crash_core.c
@@ -455,7 +455,6 @@ static int __init crash_save_vmcoreinfo_init(void)
VMCOREINFO_OFFSET(page, lru);
VMCOREINFO_OFFSET(page, _mapcount);
VMCOREINFO_OFFSET(page, private);
- VMCOREINFO_OFFSET(folio, _folio_dtor);
VMCOREINFO_OFFSET(folio, _folio_order);
VMCOREINFO_OFFSET(page, compound_head);
VMCOREINFO_OFFSET(pglist_data, node_zones);
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 04664e6918c1..c721f7ec5b6a 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -581,7 +581,7 @@ void folio_prep_large_rmappable(struct folio *folio)
{
VM_BUG_ON_FOLIO(folio_order(folio) < 2, folio);
INIT_LIST_HEAD(&folio->_deferred_list);
- folio_set_compound_dtor(folio, TRANSHUGE_PAGE_DTOR);
+ folio_set_large_rmappable(folio);
}
static inline bool is_transparent_hugepage(struct page *page)
@@ -593,7 +593,7 @@ static inline bool is_transparent_hugepage(struct page *page)
folio = page_folio(page);
return is_huge_zero_page(&folio->page) ||
- folio->_folio_dtor == TRANSHUGE_PAGE_DTOR;
+ folio_test_large_rmappable(folio);
}
static unsigned long __thp_get_unmapped_area(struct file *filp,
diff --git a/mm/internal.h b/mm/internal.h
index 1e98c867f0de..9dc7629ffbc9 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -419,7 +419,6 @@ static inline void prep_compound_head(struct page *page, unsigned int order)
{
struct folio *folio = (struct folio *)page;
- folio_set_compound_dtor(folio, COMPOUND_PAGE_DTOR);
folio_set_order(folio, order);
atomic_set(&folio->_entire_mapcount, -1);
atomic_set(&folio->_nr_pages_mapped, 0);
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index f8e276de4fd5..81b1c7e3a28b 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -582,9 +582,6 @@ static inline void free_the_page(struct page *page, unsigned int order)
* The remaining PAGE_SIZE pages are called "tail pages". PageTail() is encoded
* in bit 0 of page->compound_head. The rest of bits is pointer to head page.
*
- * The first tail page's ->compound_dtor describes how to destroy the
- * compound page.
- *
* The first tail page's ->compound_order holds the order of allocation.
* This usage means that zero-order pages may not be compound.
*/
@@ -603,14 +600,12 @@ void prep_compound_page(struct page *page, unsigned int order)
void destroy_large_folio(struct folio *folio)
{
- enum compound_dtor_id dtor = folio->_folio_dtor;
-
if (folio_test_hugetlb(folio)) {
free_huge_folio(folio);
return;
}
- if (folio_test_transhuge(folio) && dtor == TRANSHUGE_PAGE_DTOR)
+ if (folio_test_large_rmappable(folio))
folio_undo_large_rmappable(folio);
mem_cgroup_uncharge(folio);
--
2.40.1
