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authorMatthew Wilcox (Oracle) <willy@infradead.org>2023-08-16 18:11:55 +0300
committerAndrew Morton <akpm@linux-foundation.org>2023-08-22 00:28:44 +0300
commit9c5ccf2db04b8d7c3df363fdd4856c2b79ab2c6a (patch)
tree2cf6a2dffee40003d9452b72e660bb64635f0f3b
parent0f2f43fabb95192c73b19586ef7536d7ac7c2f8c (diff)
downloadlinux-9c5ccf2db04b8d7c3df363fdd4856c2b79ab2c6a.tar.xz
mm: remove HUGETLB_PAGE_DTOR
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@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: David Hildenbrand <david@redhat.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com> Cc: Yanteng Si <siyanteng@loongson.cn> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
-rw-r--r--Documentation/admin-guide/kdump/vmcoreinfo.rst10
-rw-r--r--include/linux/mm.h4
-rw-r--r--include/linux/page-flags.h43
-rw-r--r--kernel/crash_core.c2
-rw-r--r--mm/hugetlb.c49
-rw-r--r--mm/page_alloc.c2
6 files changed, 43 insertions, 67 deletions
diff --git a/Documentation/admin-guide/kdump/vmcoreinfo.rst b/Documentation/admin-guide/kdump/vmcoreinfo.rst
index c18d94fa6470..baa1c355741d 100644
--- a/Documentation/admin-guide/kdump/vmcoreinfo.rst
+++ b/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 used to filter various unnecessary for
dumping pages.
-HUGETLB_PAGE_DTOR
------------------
-
-The HUGETLB_PAGE_DTOR flag denotes hugetlbfs pages. Makedumpfile
-excludes these pages.
-
x86_64
======
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 0955b6b13fd0..e241f5ee4dc4 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1240,11 +1240,7 @@ void folio_copy(struct folio *dst, struct folio *src);
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,
};
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 9218028caf33..e9e7cc45352d 100644
--- a/include/linux/page-flags.h
+++ b/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(struct page *page)
#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 __ClearPageAnonExclusive(struct page *page)
#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)
/**
diff --git a/kernel/crash_core.c b/kernel/crash_core.c
index 90ce1dfd591c..dd5f87047d06 100644
--- a/kernel/crash_core.c
+++ b/kernel/crash_core.c
@@ -490,7 +490,7 @@ static int __init crash_save_vmcoreinfo_init(void)
#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
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 6a3c80026ab3..a82c3104337e 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1585,25 +1585,7 @@ static inline void __clear_hugetlb_destructor(struct hstate *h,
{
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 hstate *h, struct folio *folio,
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 work_struct *work)
/*
* 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(struct hstate *h, struct folio *folio)
{
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.
*
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 31fec31be31e..d96dc6a3077a 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1112,7 +1112,7 @@ static __always_inline bool free_pages_prepare(struct page *page,
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);