The patch titled
Subject: mm: remove HUGETLB_PAGE_DTOR
has been added to the -mm mm-unstable branch. Its filename is
mm-remove-hugetlb_page_dtor.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-remove-hugetlb_page_dtor.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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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>
Subject: mm: remove HUGETLB_PAGE_DTOR
Date: Wed, 16 Aug 2023 16:11:55 +0100
We can use a bit in page[1].flags to indicate that this folio belongs to
hugetlb instead of using a value in page[1].dtors. That lets
folio_test_hugetlb() become an inline function like it should be. We can
also get rid of NULL_COMPOUND_DTOR.
Link: https://lkml.kernel.org/r/20230816151201.3655946-8-willy@xxxxxxxxxxxxx
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Jens Axboe <axboe@xxxxxxxxx>
Cc: Sidhartha Kumar <sidhartha.kumar@xxxxxxxxxx>
Cc: Yanteng Si <siyanteng@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
Documentation/admin-guide/kdump/vmcoreinfo.rst | 10 ---
include/linux/mm.h | 4 -
include/linux/page-flags.h | 43 ++++++++++---
kernel/crash_core.c | 2
mm/hugetlb.c | 49 +--------------
mm/page_alloc.c | 2
6 files changed, 43 insertions(+), 67 deletions(-)
--- a/Documentation/admin-guide/kdump/vmcoreinfo.rst~mm-remove-hugetlb_page_dtor
+++ a/Documentation/admin-guide/kdump/vmcoreinfo.rst
@@ -325,8 +325,8 @@ NR_FREE_PAGES
On linux-2.6.21 or later, the number of free pages is in
vm_stat[NR_FREE_PAGES]. Used to get the number of free pages.
-PG_lru|PG_private|PG_swapcache|PG_swapbacked|PG_slab|PG_hwpoision|PG_head_mask
-------------------------------------------------------------------------------
+PG_lru|PG_private|PG_swapcache|PG_swapbacked|PG_slab|PG_hwpoision|PG_head_mask|PG_hugetlb
+-----------------------------------------------------------------------------------------
Page attributes. These flags are used to filter various unnecessary for
dumping pages.
@@ -338,12 +338,6 @@ More page attributes. These flags are us
dumping pages.
-HUGETLB_PAGE_DTOR
------------------
-
-The HUGETLB_PAGE_DTOR flag denotes hugetlbfs pages. Makedumpfile
-excludes these pages.
-
x86_64
======
--- a/include/linux/mm.h~mm-remove-hugetlb_page_dtor
+++ a/include/linux/mm.h
@@ -1273,11 +1273,7 @@ void folio_copy(struct folio *dst, struc
unsigned long nr_free_buffer_pages(void);
enum compound_dtor_id {
- NULL_COMPOUND_DTOR,
COMPOUND_PAGE_DTOR,
-#ifdef CONFIG_HUGETLB_PAGE
- HUGETLB_PAGE_DTOR,
-#endif
TRANSHUGE_PAGE_DTOR,
NR_COMPOUND_DTORS,
};
--- a/include/linux/page-flags.h~mm-remove-hugetlb_page_dtor
+++ a/include/linux/page-flags.h
@@ -171,15 +171,6 @@ enum pageflags {
/* Remapped by swiotlb-xen. */
PG_xen_remapped = PG_owner_priv_1,
-#ifdef CONFIG_MEMORY_FAILURE
- /*
- * Compound pages. Stored in first tail page's flags.
- * Indicates that at least one subpage is hwpoisoned in the
- * THP.
- */
- PG_has_hwpoisoned = PG_error,
-#endif
-
/* non-lru isolated movable page */
PG_isolated = PG_reclaim,
@@ -190,6 +181,15 @@ enum pageflags {
/* For self-hosted memmap pages */
PG_vmemmap_self_hosted = PG_owner_priv_1,
#endif
+
+ /*
+ * Flags only valid for compound pages. Stored in first tail page's
+ * flags word.
+ */
+
+ /* At least one page in this folio has the hwpoison flag set */
+ PG_has_hwpoisoned = PG_error,
+ PG_hugetlb = PG_active,
};
#define PAGEFLAGS_MASK ((1UL << NR_PAGEFLAGS) - 1)
@@ -812,7 +812,23 @@ static inline void ClearPageCompound(str
#ifdef CONFIG_HUGETLB_PAGE
int PageHuge(struct page *page);
-bool folio_test_hugetlb(struct folio *folio);
+SETPAGEFLAG(HugeTLB, hugetlb, PF_SECOND)
+CLEARPAGEFLAG(HugeTLB, hugetlb, PF_SECOND)
+
+/**
+ * folio_test_hugetlb - Determine if the folio belongs to hugetlbfs
+ * @folio: The folio to test.
+ *
+ * Context: Any context. Caller should have a reference on the folio to
+ * prevent it from being turned into a tail page.
+ * Return: True for hugetlbfs folios, false for anon folios or folios
+ * belonging to other filesystems.
+ */
+static inline bool folio_test_hugetlb(struct folio *folio)
+{
+ return folio_test_large(folio) &&
+ test_bit(PG_hugetlb, folio_flags(folio, 1));
+}
#else
TESTPAGEFLAG_FALSE(Huge, hugetlb)
#endif
@@ -1056,6 +1072,13 @@ static __always_inline void __ClearPageA
#define PAGE_FLAGS_CHECK_AT_PREP \
((PAGEFLAGS_MASK & ~__PG_HWPOISON) | LRU_GEN_MASK | LRU_REFS_MASK)
+/*
+ * Flags stored in the second page of a compound page. They may overlap
+ * the CHECK_AT_FREE flags above, so need to be cleared.
+ */
+#define PAGE_FLAGS_SECOND \
+ (1UL << PG_has_hwpoisoned | 1UL << PG_hugetlb)
+
#define PAGE_FLAGS_PRIVATE \
(1UL << PG_private | 1UL << PG_private_2)
/**
--- a/kernel/crash_core.c~mm-remove-hugetlb_page_dtor
+++ a/kernel/crash_core.c
@@ -490,7 +490,7 @@ static int __init crash_save_vmcoreinfo_
#define PAGE_BUDDY_MAPCOUNT_VALUE (~PG_buddy)
VMCOREINFO_NUMBER(PAGE_BUDDY_MAPCOUNT_VALUE);
#ifdef CONFIG_HUGETLB_PAGE
- VMCOREINFO_NUMBER(HUGETLB_PAGE_DTOR);
+ VMCOREINFO_NUMBER(PG_hugetlb);
#define PAGE_OFFLINE_MAPCOUNT_VALUE (~PG_offline)
VMCOREINFO_NUMBER(PAGE_OFFLINE_MAPCOUNT_VALUE);
#endif
--- a/mm/hugetlb.c~mm-remove-hugetlb_page_dtor
+++ a/mm/hugetlb.c
@@ -1585,25 +1585,7 @@ static inline void __clear_hugetlb_destr
{
lockdep_assert_held(&hugetlb_lock);
- /*
- * Very subtle
- *
- * For non-gigantic pages set the destructor to the normal compound
- * page dtor. This is needed in case someone takes an additional
- * temporary ref to the page, and freeing is delayed until they drop
- * their reference.
- *
- * For gigantic pages set the destructor to the null dtor. This
- * destructor will never be called. Before freeing the gigantic
- * page destroy_compound_gigantic_folio will turn the folio into a
- * simple group of pages. After this the destructor does not
- * apply.
- *
- */
- if (hstate_is_gigantic(h))
- folio_set_compound_dtor(folio, NULL_COMPOUND_DTOR);
- else
- folio_set_compound_dtor(folio, COMPOUND_PAGE_DTOR);
+ folio_clear_hugetlb(folio);
}
/*
@@ -1690,7 +1672,7 @@ static void add_hugetlb_folio(struct hst
h->surplus_huge_pages_node[nid]++;
}
- folio_set_compound_dtor(folio, HUGETLB_PAGE_DTOR);
+ folio_set_hugetlb(folio);
folio_change_private(folio, NULL);
/*
* We have to set hugetlb_vmemmap_optimized again as above
@@ -1814,9 +1796,8 @@ static void free_hpage_workfn(struct wor
/*
* The VM_BUG_ON_FOLIO(!folio_test_hugetlb(folio), folio) in
* folio_hstate() is going to trigger because a previous call to
- * remove_hugetlb_folio() will call folio_set_compound_dtor
- * (folio, NULL_COMPOUND_DTOR), so do not use folio_hstate()
- * directly.
+ * remove_hugetlb_folio() will clear the hugetlb bit, so do
+ * not use folio_hstate() directly.
*/
h = size_to_hstate(page_size(page));
@@ -1955,7 +1936,7 @@ static void __prep_new_hugetlb_folio(str
{
hugetlb_vmemmap_optimize(h, &folio->page);
INIT_LIST_HEAD(&folio->lru);
- folio_set_compound_dtor(folio, HUGETLB_PAGE_DTOR);
+ folio_set_hugetlb(folio);
hugetlb_set_folio_subpool(folio, NULL);
set_hugetlb_cgroup(folio, NULL);
set_hugetlb_cgroup_rsvd(folio, NULL);
@@ -2070,28 +2051,10 @@ int PageHuge(struct page *page)
if (!PageCompound(page))
return 0;
folio = page_folio(page);
- return folio->_folio_dtor == HUGETLB_PAGE_DTOR;
+ return folio_test_hugetlb(folio);
}
EXPORT_SYMBOL_GPL(PageHuge);
-/**
- * folio_test_hugetlb - Determine if the folio belongs to hugetlbfs
- * @folio: The folio to test.
- *
- * Context: Any context. Caller should have a reference on the folio to
- * prevent it from being turned into a tail page.
- * Return: True for hugetlbfs folios, false for anon folios or folios
- * belonging to other filesystems.
- */
-bool folio_test_hugetlb(struct folio *folio)
-{
- if (!folio_test_large(folio))
- return false;
-
- return folio->_folio_dtor == HUGETLB_PAGE_DTOR;
-}
-EXPORT_SYMBOL_GPL(folio_test_hugetlb);
-
/*
* Find and lock address space (mapping) in write mode.
*
--- a/mm/page_alloc.c~mm-remove-hugetlb_page_dtor
+++ a/mm/page_alloc.c
@@ -1112,7 +1112,7 @@ static __always_inline bool free_pages_p
VM_BUG_ON_PAGE(compound && compound_order(page) != order, page);
if (compound)
- ClearPageHasHWPoisoned(page);
+ page[1].flags &= ~PAGE_FLAGS_SECOND;
for (i = 1; i < (1 << order); i++) {
if (compound)
bad += free_tail_page_prepare(page, page + i);
_
Patches currently in -mm which might be from willy@xxxxxxxxxxxxx are
mm-memoryc-fix-mismerge.patch
mm-drop-per-vma-lock-when-returning-vm_fault_retry-or-vm_fault_completed-fix.patch
zswap-make-zswap_store-take-a-folio.patch
memcg-convert-get_obj_cgroup_from_page-to-get_obj_cgroup_from_folio.patch
swap-remove-some-calls-to-compound_head-in-swap_readpage.patch
zswap-make-zswap_load-take-a-folio.patch
mm-improve-the-comment-in-isolate_migratepages_block.patch
minmax-add-in_range-macro.patch
mm-convert-page_table_check_pte_set-to-page_table_check_ptes_set.patch
mm-add-generic-flush_icache_pages-and-documentation.patch
mm-add-folio_flush_mapping.patch
mm-remove-arch_implements_flush_dcache_folio.patch
mm-add-default-definition-of-set_ptes.patch
alpha-implement-the-new-page-table-range-api.patch
arc-implement-the-new-page-table-range-api.patch
arm-implement-the-new-page-table-range-api.patch
arm64-implement-the-new-page-table-range-api.patch
csky-implement-the-new-page-table-range-api.patch
hexagon-implement-the-new-page-table-range-api.patch
ia64-implement-the-new-page-table-range-api.patch
ia64-implement-the-new-page-table-range-api-fix.patch
loongarch-implement-the-new-page-table-range-api.patch
m68k-implement-the-new-page-table-range-api.patch
microblaze-implement-the-new-page-table-range-api.patch
mips-implement-the-new-page-table-range-api.patch
nios2-implement-the-new-page-table-range-api.patch
openrisc-implement-the-new-page-table-range-api.patch
parisc-implement-the-new-page-table-range-api.patch
powerpc-implement-the-new-page-table-range-api.patch
powerpc-implement-the-new-page-table-range-api-fix.patch
riscv-implement-the-new-page-table-range-api.patch
s390-implement-the-new-page-table-range-api.patch
sh-implement-the-new-page-table-range-api.patch
sparc32-implement-the-new-page-table-range-api.patch
sparc64-implement-the-new-page-table-range-api.patch
um-implement-the-new-page-table-range-api.patch
x86-implement-the-new-page-table-range-api.patch
xtensa-implement-the-new-page-table-range-api.patch
mm-remove-page_mapping_file.patch
mm-rationalise-flush_icache_pages-and-flush_icache_page.patch
mm-tidy-up-set_ptes-definition.patch
mm-use-flush_icache_pages-in-do_set_pmd.patch
mm-call-update_mmu_cache_range-in-more-page-fault-handling-paths.patch
mm-allow-fault_dirty_shared_page-to-be-called-under-the-vma-lock.patch
io_uring-stop-calling-free_compound_page.patch
mm-call-free_huge_page-directly.patch
mm-convert-free_huge_page-to-free_huge_folio.patch
mm-convert-free_transhuge_folio-to-folio_undo_large_rmappable.patch
mm-convert-prep_transhuge_page-to-folio_prep_large_rmappable.patch
mm-remove-free_compound_page-and-the-compound_page_dtors-array.patch
mm-remove-hugetlb_page_dtor.patch
mm-add-large_rmappable-page-flag.patch
mm-rearrange-page-flags.patch
mm-free-up-a-word-in-the-first-tail-page.patch
mm-remove-folio_test_transhuge.patch
mm-add-tail-private-fields-to-struct-folio.patch
mm-convert-split_huge_pages_pid-to-use-a-folio.patch
