The patch titled
Subject: mm: convert huge_zero_page to huge_zero_folio
has been added to the -mm mm-unstable branch. Its filename is
mm-convert-huge_zero_page-to-huge_zero_folio.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-convert-huge_zero_page-to-huge_zero_folio.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>
Subject: mm: convert huge_zero_page to huge_zero_folio
Date: Tue, 26 Mar 2024 20:28:25 +0000
With all callers of is_huge_zero_page() converted, we can now switch the
huge_zero_page itself from being a compound page to a folio.
Link: https://lkml.kernel.org/r/20240326202833.523759-6-willy@xxxxxxxxxxxxx
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/huge_mm.h | 21 ++++++++-------------
mm/huge_memory.c | 28 ++++++++++++++--------------
2 files changed, 22 insertions(+), 27 deletions(-)
--- a/include/linux/huge_mm.h~mm-convert-huge_zero_page-to-huge_zero_folio
+++ a/include/linux/huge_mm.h
@@ -348,17 +348,12 @@ struct page *follow_devmap_pud(struct vm
vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf);
-extern struct page *huge_zero_page;
+extern struct folio *huge_zero_folio;
extern unsigned long huge_zero_pfn;
-static inline bool is_huge_zero_page(const struct page *page)
-{
- return READ_ONCE(huge_zero_page) == page;
-}
-
static inline bool is_huge_zero_folio(const struct folio *folio)
{
- return READ_ONCE(huge_zero_page) == &folio->page;
+ return READ_ONCE(huge_zero_folio) == folio;
}
static inline bool is_huge_zero_pmd(pmd_t pmd)
@@ -371,9 +366,14 @@ static inline bool is_huge_zero_pud(pud_
return false;
}
-struct page *mm_get_huge_zero_page(struct mm_struct *mm);
+struct folio *mm_get_huge_zero_folio(struct mm_struct *mm);
void mm_put_huge_zero_page(struct mm_struct *mm);
+static inline struct page *mm_get_huge_zero_page(struct mm_struct *mm)
+{
+ return &mm_get_huge_zero_folio(mm)->page;
+}
+
#define mk_huge_pmd(page, prot) pmd_mkhuge(mk_pmd(page, prot))
static inline bool thp_migration_supported(void)
@@ -485,11 +485,6 @@ static inline vm_fault_t do_huge_pmd_num
return 0;
}
-static inline bool is_huge_zero_page(const struct page *page)
-{
- return false;
-}
-
static inline bool is_huge_zero_folio(const struct folio *folio)
{
return false;
--- a/mm/huge_memory.c~mm-convert-huge_zero_page-to-huge_zero_folio
+++ a/mm/huge_memory.c
@@ -74,7 +74,7 @@ static unsigned long deferred_split_scan
struct shrink_control *sc);
static atomic_t huge_zero_refcount;
-struct page *huge_zero_page __read_mostly;
+struct folio *huge_zero_folio __read_mostly;
unsigned long huge_zero_pfn __read_mostly = ~0UL;
unsigned long huge_anon_orders_always __read_mostly;
unsigned long huge_anon_orders_madvise __read_mostly;
@@ -192,24 +192,24 @@ unsigned long __thp_vma_allowable_orders
static bool get_huge_zero_page(void)
{
- struct page *zero_page;
+ struct folio *zero_folio;
retry:
if (likely(atomic_inc_not_zero(&huge_zero_refcount)))
return true;
- zero_page = alloc_pages((GFP_TRANSHUGE | __GFP_ZERO) & ~__GFP_MOVABLE,
+ zero_folio = folio_alloc((GFP_TRANSHUGE | __GFP_ZERO) & ~__GFP_MOVABLE,
HPAGE_PMD_ORDER);
- if (!zero_page) {
+ if (!zero_folio) {
count_vm_event(THP_ZERO_PAGE_ALLOC_FAILED);
return false;
}
preempt_disable();
- if (cmpxchg(&huge_zero_page, NULL, zero_page)) {
+ if (cmpxchg(&huge_zero_folio, NULL, zero_folio)) {
preempt_enable();
- __free_pages(zero_page, compound_order(zero_page));
+ folio_put(zero_folio);
goto retry;
}
- WRITE_ONCE(huge_zero_pfn, page_to_pfn(zero_page));
+ WRITE_ONCE(huge_zero_pfn, folio_pfn(zero_folio));
/* We take additional reference here. It will be put back by shrinker */
atomic_set(&huge_zero_refcount, 2);
@@ -227,10 +227,10 @@ static void put_huge_zero_page(void)
BUG_ON(atomic_dec_and_test(&huge_zero_refcount));
}
-struct page *mm_get_huge_zero_page(struct mm_struct *mm)
+struct folio *mm_get_huge_zero_folio(struct mm_struct *mm)
{
if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags))
- return READ_ONCE(huge_zero_page);
+ return READ_ONCE(huge_zero_folio);
if (!get_huge_zero_page())
return NULL;
@@ -238,7 +238,7 @@ struct page *mm_get_huge_zero_page(struc
if (test_and_set_bit(MMF_HUGE_ZERO_PAGE, &mm->flags))
put_huge_zero_page();
- return READ_ONCE(huge_zero_page);
+ return READ_ONCE(huge_zero_folio);
}
void mm_put_huge_zero_page(struct mm_struct *mm)
@@ -258,10 +258,10 @@ static unsigned long shrink_huge_zero_pa
struct shrink_control *sc)
{
if (atomic_cmpxchg(&huge_zero_refcount, 1, 0) == 1) {
- struct page *zero_page = xchg(&huge_zero_page, NULL);
- BUG_ON(zero_page == NULL);
+ struct folio *zero_folio = xchg(&huge_zero_folio, NULL);
+ BUG_ON(zero_folio == NULL);
WRITE_ONCE(huge_zero_pfn, ~0UL);
- __free_pages(zero_page, compound_order(zero_page));
+ folio_put(zero_folio);
return HPAGE_PMD_NR;
}
@@ -1340,7 +1340,7 @@ int copy_huge_pmd(struct mm_struct *dst_
* since we already have a zero page to copy. It just takes a
* reference.
*/
- mm_get_huge_zero_page(dst_mm);
+ mm_get_huge_zero_folio(dst_mm);
goto out_zero_page;
}
_
Patches currently in -mm which might be from willy@xxxxxxxxxxxxx are
mm-always-initialise-folio-_deferred_list.patch
mm-create-folio_flag_false-and-folio_type_ops-macros.patch
mm-remove-folio_prep_large_rmappable.patch
mm-support-page_mapcount-on-page_has_type-pages.patch
mm-turn-folio_test_hugetlb-into-a-pagetype.patch
mm-turn-folio_test_hugetlb-into-a-pagetype-fix.patch
mm-remove-a-call-to-compound_head-from-is_page_hwpoison.patch
mm-free-up-pg_slab.patch
mm-free-up-pg_slab-fix.patch
mm-improve-dumping-of-mapcount-and-page_type.patch
hugetlb-remove-mention-of-destructors.patch
sh-remove-use-of-pg_arch_1-on-individual-pages.patch
xtensa-remove-uses-of-pg_arch_1-on-individual-pages.patch
mm-make-page_ext_get-take-a-const-argument.patch
mm-make-folio_test_idle-and-folio_test_young-take-a-const-argument.patch
mm-make-is_free_buddy_page-take-a-const-argument.patch
mm-make-page_mapped-take-a-const-argument.patch
mm-convert-arch_clear_hugepage_flags-to-take-a-folio.patch
slub-remove-use-of-page-flags.patch
remove-references-to-page-flags-in-documentation.patch
proc-rewrite-stable_page_flags.patch
sparc-use-is_huge_zero_pmd.patch
mm-add-is_huge_zero_folio.patch
mm-add-pmd_folio.patch
mm-convert-migrate_vma_collect_pmd-to-use-a-folio.patch
mm-convert-huge_zero_page-to-huge_zero_folio.patch
mm-convert-do_huge_pmd_anonymous_page-to-huge_zero_folio.patch
dax-use-huge_zero_folio.patch
mm-rename-mm_put_huge_zero_page-to-mm_put_huge_zero_folio.patch
