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.
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
---
.../admin-guide/kdump/vmcoreinfo.rst | 10 +---
include/linux/mm.h | 2 -
include/linux/page-flags.h | 21 +++++++-
kernel/crash_core.c | 2 +-
mm/hugetlb.c | 49 +++----------------
5 files changed, 29 insertions(+), 55 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 cf6707a7069e..c8c8b1fd64d3 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1269,9 +1269,7 @@ unsigned long nr_free_buffer_pages(void);
/* Compound pages may have a special destructor */
enum compound_dtor_id {
- NULL_COMPOUND_DTOR,
COMPOUND_PAGE_DTOR,
- HUGETLB_PAGE_DTOR,
TRANSHUGE_PAGE_DTOR,
NR_COMPOUND_DTORS
};
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 92a2063a0a23..01d98695e79f 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -180,6 +180,9 @@ enum pageflags {
PG_has_hwpoisoned = PG_error,
#endif
+ /* Is a hugetlb page. Stored in first tail page. */
+ PG_hugetlb = PG_writeback,
+
/* non-lru isolated movable page */
PG_isolated = PG_reclaim,
@@ -812,7 +815,23 @@ 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
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 bc340f5dbbd4..a1cebcee6503 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.
*
--
2.40.1
