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Message-ID: <20250811112631.759341-8-david@redhat.com>
Date: Mon, 11 Aug 2025 13:26:27 +0200
From: David Hildenbrand <david@...hat.com>
To: linux-kernel@...r.kernel.org
Cc: linux-mm@...ck.org,
xen-devel@...ts.xenproject.org,
linux-fsdevel@...r.kernel.org,
nvdimm@...ts.linux.dev,
linuxppc-dev@...ts.ozlabs.org,
David Hildenbrand <david@...hat.com>,
Andrew Morton <akpm@...ux-foundation.org>,
Madhavan Srinivasan <maddy@...ux.ibm.com>,
Michael Ellerman <mpe@...erman.id.au>,
Nicholas Piggin <npiggin@...il.com>,
Christophe Leroy <christophe.leroy@...roup.eu>,
Juergen Gross <jgross@...e.com>,
Stefano Stabellini <sstabellini@...nel.org>,
Oleksandr Tyshchenko <oleksandr_tyshchenko@...m.com>,
Dan Williams <dan.j.williams@...el.com>,
Matthew Wilcox <willy@...radead.org>,
Jan Kara <jack@...e.cz>,
Alexander Viro <viro@...iv.linux.org.uk>,
Christian Brauner <brauner@...nel.org>,
Lorenzo Stoakes <lorenzo.stoakes@...cle.com>,
"Liam R. Howlett" <Liam.Howlett@...cle.com>,
Vlastimil Babka <vbabka@...e.cz>,
Mike Rapoport <rppt@...nel.org>,
Suren Baghdasaryan <surenb@...gle.com>,
Michal Hocko <mhocko@...e.com>,
Zi Yan <ziy@...dia.com>,
Baolin Wang <baolin.wang@...ux.alibaba.com>,
Nico Pache <npache@...hat.com>,
Ryan Roberts <ryan.roberts@....com>,
Dev Jain <dev.jain@....com>,
Barry Song <baohua@...nel.org>,
Jann Horn <jannh@...gle.com>,
Pedro Falcato <pfalcato@...e.de>,
Hugh Dickins <hughd@...gle.com>,
Oscar Salvador <osalvador@...e.de>,
Lance Yang <lance.yang@...ux.dev>
Subject: [PATCH v3 07/11] mm/rmap: convert "enum rmap_level" to "enum pgtable_level"
Let's factor it out, and convert all checks for unsupported levels to
BUILD_BUG(). The code is written in a way such that force-inlining will
optimize out the levels.
Signed-off-by: David Hildenbrand <david@...hat.com>
---
include/linux/pgtable.h | 8 ++++++
include/linux/rmap.h | 60 +++++++++++++++++++----------------------
mm/rmap.c | 56 +++++++++++++++++++++-----------------
3 files changed, 66 insertions(+), 58 deletions(-)
diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index 4c035637eeb77..bff5c4241bf2e 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h
@@ -1958,6 +1958,14 @@ static inline bool arch_has_pfn_modify_check(void)
/* Page-Table Modification Mask */
typedef unsigned int pgtbl_mod_mask;
+enum pgtable_level {
+ PGTABLE_LEVEL_PTE = 0,
+ PGTABLE_LEVEL_PMD,
+ PGTABLE_LEVEL_PUD,
+ PGTABLE_LEVEL_P4D,
+ PGTABLE_LEVEL_PGD,
+};
+
#endif /* !__ASSEMBLY__ */
#if !defined(MAX_POSSIBLE_PHYSMEM_BITS) && !defined(CONFIG_64BIT)
diff --git a/include/linux/rmap.h b/include/linux/rmap.h
index 6cd020eea37a2..9d40d127bdb78 100644
--- a/include/linux/rmap.h
+++ b/include/linux/rmap.h
@@ -394,18 +394,8 @@ typedef int __bitwise rmap_t;
/* The anonymous (sub)page is exclusive to a single process. */
#define RMAP_EXCLUSIVE ((__force rmap_t)BIT(0))
-/*
- * Internally, we're using an enum to specify the granularity. We make the
- * compiler emit specialized code for each granularity.
- */
-enum rmap_level {
- RMAP_LEVEL_PTE = 0,
- RMAP_LEVEL_PMD,
- RMAP_LEVEL_PUD,
-};
-
static inline void __folio_rmap_sanity_checks(const struct folio *folio,
- const struct page *page, int nr_pages, enum rmap_level level)
+ const struct page *page, int nr_pages, enum pgtable_level level)
{
/* hugetlb folios are handled separately. */
VM_WARN_ON_FOLIO(folio_test_hugetlb(folio), folio);
@@ -427,18 +417,18 @@ static inline void __folio_rmap_sanity_checks(const struct folio *folio,
VM_WARN_ON_FOLIO(page_folio(page + nr_pages - 1) != folio, folio);
switch (level) {
- case RMAP_LEVEL_PTE:
+ case PGTABLE_LEVEL_PTE:
break;
- case RMAP_LEVEL_PMD:
+ case PGTABLE_LEVEL_PMD:
/*
* We don't support folios larger than a single PMD yet. So
- * when RMAP_LEVEL_PMD is set, we assume that we are creating
+ * when PGTABLE_LEVEL_PMD is set, we assume that we are creating
* a single "entire" mapping of the folio.
*/
VM_WARN_ON_FOLIO(folio_nr_pages(folio) != HPAGE_PMD_NR, folio);
VM_WARN_ON_FOLIO(nr_pages != HPAGE_PMD_NR, folio);
break;
- case RMAP_LEVEL_PUD:
+ case PGTABLE_LEVEL_PUD:
/*
* Assume that we are creating a single "entire" mapping of the
* folio.
@@ -447,7 +437,7 @@ static inline void __folio_rmap_sanity_checks(const struct folio *folio,
VM_WARN_ON_FOLIO(nr_pages != HPAGE_PUD_NR, folio);
break;
default:
- VM_WARN_ON_ONCE(true);
+ BUILD_BUG();
}
/*
@@ -567,14 +557,14 @@ static inline void hugetlb_remove_rmap(struct folio *folio)
static __always_inline void __folio_dup_file_rmap(struct folio *folio,
struct page *page, int nr_pages, struct vm_area_struct *dst_vma,
- enum rmap_level level)
+ enum pgtable_level level)
{
const int orig_nr_pages = nr_pages;
__folio_rmap_sanity_checks(folio, page, nr_pages, level);
switch (level) {
- case RMAP_LEVEL_PTE:
+ case PGTABLE_LEVEL_PTE:
if (!folio_test_large(folio)) {
atomic_inc(&folio->_mapcount);
break;
@@ -587,11 +577,13 @@ static __always_inline void __folio_dup_file_rmap(struct folio *folio,
}
folio_add_large_mapcount(folio, orig_nr_pages, dst_vma);
break;
- case RMAP_LEVEL_PMD:
- case RMAP_LEVEL_PUD:
+ case PGTABLE_LEVEL_PMD:
+ case PGTABLE_LEVEL_PUD:
atomic_inc(&folio->_entire_mapcount);
folio_inc_large_mapcount(folio, dst_vma);
break;
+ default:
+ BUILD_BUG();
}
}
@@ -609,13 +601,13 @@ static __always_inline void __folio_dup_file_rmap(struct folio *folio,
static inline void folio_dup_file_rmap_ptes(struct folio *folio,
struct page *page, int nr_pages, struct vm_area_struct *dst_vma)
{
- __folio_dup_file_rmap(folio, page, nr_pages, dst_vma, RMAP_LEVEL_PTE);
+ __folio_dup_file_rmap(folio, page, nr_pages, dst_vma, PGTABLE_LEVEL_PTE);
}
static __always_inline void folio_dup_file_rmap_pte(struct folio *folio,
struct page *page, struct vm_area_struct *dst_vma)
{
- __folio_dup_file_rmap(folio, page, 1, dst_vma, RMAP_LEVEL_PTE);
+ __folio_dup_file_rmap(folio, page, 1, dst_vma, PGTABLE_LEVEL_PTE);
}
/**
@@ -632,7 +624,7 @@ static inline void folio_dup_file_rmap_pmd(struct folio *folio,
struct page *page, struct vm_area_struct *dst_vma)
{
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
- __folio_dup_file_rmap(folio, page, HPAGE_PMD_NR, dst_vma, RMAP_LEVEL_PTE);
+ __folio_dup_file_rmap(folio, page, HPAGE_PMD_NR, dst_vma, PGTABLE_LEVEL_PTE);
#else
WARN_ON_ONCE(true);
#endif
@@ -640,7 +632,7 @@ static inline void folio_dup_file_rmap_pmd(struct folio *folio,
static __always_inline int __folio_try_dup_anon_rmap(struct folio *folio,
struct page *page, int nr_pages, struct vm_area_struct *dst_vma,
- struct vm_area_struct *src_vma, enum rmap_level level)
+ struct vm_area_struct *src_vma, enum pgtable_level level)
{
const int orig_nr_pages = nr_pages;
bool maybe_pinned;
@@ -665,7 +657,7 @@ static __always_inline int __folio_try_dup_anon_rmap(struct folio *folio,
* copying if the folio maybe pinned.
*/
switch (level) {
- case RMAP_LEVEL_PTE:
+ case PGTABLE_LEVEL_PTE:
if (unlikely(maybe_pinned)) {
for (i = 0; i < nr_pages; i++)
if (PageAnonExclusive(page + i))
@@ -687,8 +679,8 @@ static __always_inline int __folio_try_dup_anon_rmap(struct folio *folio,
} while (page++, --nr_pages > 0);
folio_add_large_mapcount(folio, orig_nr_pages, dst_vma);
break;
- case RMAP_LEVEL_PMD:
- case RMAP_LEVEL_PUD:
+ case PGTABLE_LEVEL_PMD:
+ case PGTABLE_LEVEL_PUD:
if (PageAnonExclusive(page)) {
if (unlikely(maybe_pinned))
return -EBUSY;
@@ -697,6 +689,8 @@ static __always_inline int __folio_try_dup_anon_rmap(struct folio *folio,
atomic_inc(&folio->_entire_mapcount);
folio_inc_large_mapcount(folio, dst_vma);
break;
+ default:
+ BUILD_BUG();
}
return 0;
}
@@ -730,7 +724,7 @@ static inline int folio_try_dup_anon_rmap_ptes(struct folio *folio,
struct vm_area_struct *src_vma)
{
return __folio_try_dup_anon_rmap(folio, page, nr_pages, dst_vma,
- src_vma, RMAP_LEVEL_PTE);
+ src_vma, PGTABLE_LEVEL_PTE);
}
static __always_inline int folio_try_dup_anon_rmap_pte(struct folio *folio,
@@ -738,7 +732,7 @@ static __always_inline int folio_try_dup_anon_rmap_pte(struct folio *folio,
struct vm_area_struct *src_vma)
{
return __folio_try_dup_anon_rmap(folio, page, 1, dst_vma, src_vma,
- RMAP_LEVEL_PTE);
+ PGTABLE_LEVEL_PTE);
}
/**
@@ -770,7 +764,7 @@ static inline int folio_try_dup_anon_rmap_pmd(struct folio *folio,
{
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
return __folio_try_dup_anon_rmap(folio, page, HPAGE_PMD_NR, dst_vma,
- src_vma, RMAP_LEVEL_PMD);
+ src_vma, PGTABLE_LEVEL_PMD);
#else
WARN_ON_ONCE(true);
return -EBUSY;
@@ -778,7 +772,7 @@ static inline int folio_try_dup_anon_rmap_pmd(struct folio *folio,
}
static __always_inline int __folio_try_share_anon_rmap(struct folio *folio,
- struct page *page, int nr_pages, enum rmap_level level)
+ struct page *page, int nr_pages, enum pgtable_level level)
{
VM_WARN_ON_FOLIO(!folio_test_anon(folio), folio);
VM_WARN_ON_FOLIO(!PageAnonExclusive(page), folio);
@@ -873,7 +867,7 @@ static __always_inline int __folio_try_share_anon_rmap(struct folio *folio,
static inline int folio_try_share_anon_rmap_pte(struct folio *folio,
struct page *page)
{
- return __folio_try_share_anon_rmap(folio, page, 1, RMAP_LEVEL_PTE);
+ return __folio_try_share_anon_rmap(folio, page, 1, PGTABLE_LEVEL_PTE);
}
/**
@@ -904,7 +898,7 @@ static inline int folio_try_share_anon_rmap_pmd(struct folio *folio,
{
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
return __folio_try_share_anon_rmap(folio, page, HPAGE_PMD_NR,
- RMAP_LEVEL_PMD);
+ PGTABLE_LEVEL_PMD);
#else
WARN_ON_ONCE(true);
return -EBUSY;
diff --git a/mm/rmap.c b/mm/rmap.c
index 84a8d8b02ef77..0e9c4041f8687 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1265,7 +1265,7 @@ static void __folio_mod_stat(struct folio *folio, int nr, int nr_pmdmapped)
static __always_inline void __folio_add_rmap(struct folio *folio,
struct page *page, int nr_pages, struct vm_area_struct *vma,
- enum rmap_level level)
+ enum pgtable_level level)
{
atomic_t *mapped = &folio->_nr_pages_mapped;
const int orig_nr_pages = nr_pages;
@@ -1274,7 +1274,7 @@ static __always_inline void __folio_add_rmap(struct folio *folio,
__folio_rmap_sanity_checks(folio, page, nr_pages, level);
switch (level) {
- case RMAP_LEVEL_PTE:
+ case PGTABLE_LEVEL_PTE:
if (!folio_test_large(folio)) {
nr = atomic_inc_and_test(&folio->_mapcount);
break;
@@ -1300,11 +1300,11 @@ static __always_inline void __folio_add_rmap(struct folio *folio,
folio_add_large_mapcount(folio, orig_nr_pages, vma);
break;
- case RMAP_LEVEL_PMD:
- case RMAP_LEVEL_PUD:
+ case PGTABLE_LEVEL_PMD:
+ case PGTABLE_LEVEL_PUD:
first = atomic_inc_and_test(&folio->_entire_mapcount);
if (IS_ENABLED(CONFIG_NO_PAGE_MAPCOUNT)) {
- if (level == RMAP_LEVEL_PMD && first)
+ if (level == PGTABLE_LEVEL_PMD && first)
nr_pmdmapped = folio_large_nr_pages(folio);
nr = folio_inc_return_large_mapcount(folio, vma);
if (nr == 1)
@@ -1323,7 +1323,7 @@ static __always_inline void __folio_add_rmap(struct folio *folio,
* We only track PMD mappings of PMD-sized
* folios separately.
*/
- if (level == RMAP_LEVEL_PMD)
+ if (level == PGTABLE_LEVEL_PMD)
nr_pmdmapped = nr_pages;
nr = nr_pages - (nr & FOLIO_PAGES_MAPPED);
/* Raced ahead of a remove and another add? */
@@ -1336,6 +1336,8 @@ static __always_inline void __folio_add_rmap(struct folio *folio,
}
folio_inc_large_mapcount(folio, vma);
break;
+ default:
+ BUILD_BUG();
}
__folio_mod_stat(folio, nr, nr_pmdmapped);
}
@@ -1427,7 +1429,7 @@ static void __page_check_anon_rmap(const struct folio *folio,
static __always_inline void __folio_add_anon_rmap(struct folio *folio,
struct page *page, int nr_pages, struct vm_area_struct *vma,
- unsigned long address, rmap_t flags, enum rmap_level level)
+ unsigned long address, rmap_t flags, enum pgtable_level level)
{
int i;
@@ -1440,20 +1442,22 @@ static __always_inline void __folio_add_anon_rmap(struct folio *folio,
if (flags & RMAP_EXCLUSIVE) {
switch (level) {
- case RMAP_LEVEL_PTE:
+ case PGTABLE_LEVEL_PTE:
for (i = 0; i < nr_pages; i++)
SetPageAnonExclusive(page + i);
break;
- case RMAP_LEVEL_PMD:
+ case PGTABLE_LEVEL_PMD:
SetPageAnonExclusive(page);
break;
- case RMAP_LEVEL_PUD:
+ case PGTABLE_LEVEL_PUD:
/*
* Keep the compiler happy, we don't support anonymous
* PUD mappings.
*/
WARN_ON_ONCE(1);
break;
+ default:
+ BUILD_BUG();
}
}
@@ -1507,7 +1511,7 @@ void folio_add_anon_rmap_ptes(struct folio *folio, struct page *page,
rmap_t flags)
{
__folio_add_anon_rmap(folio, page, nr_pages, vma, address, flags,
- RMAP_LEVEL_PTE);
+ PGTABLE_LEVEL_PTE);
}
/**
@@ -1528,7 +1532,7 @@ void folio_add_anon_rmap_pmd(struct folio *folio, struct page *page,
{
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
__folio_add_anon_rmap(folio, page, HPAGE_PMD_NR, vma, address, flags,
- RMAP_LEVEL_PMD);
+ PGTABLE_LEVEL_PMD);
#else
WARN_ON_ONCE(true);
#endif
@@ -1609,7 +1613,7 @@ void folio_add_new_anon_rmap(struct folio *folio, struct vm_area_struct *vma,
static __always_inline void __folio_add_file_rmap(struct folio *folio,
struct page *page, int nr_pages, struct vm_area_struct *vma,
- enum rmap_level level)
+ enum pgtable_level level)
{
VM_WARN_ON_FOLIO(folio_test_anon(folio), folio);
@@ -1634,7 +1638,7 @@ static __always_inline void __folio_add_file_rmap(struct folio *folio,
void folio_add_file_rmap_ptes(struct folio *folio, struct page *page,
int nr_pages, struct vm_area_struct *vma)
{
- __folio_add_file_rmap(folio, page, nr_pages, vma, RMAP_LEVEL_PTE);
+ __folio_add_file_rmap(folio, page, nr_pages, vma, PGTABLE_LEVEL_PTE);
}
/**
@@ -1651,7 +1655,7 @@ void folio_add_file_rmap_pmd(struct folio *folio, struct page *page,
struct vm_area_struct *vma)
{
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
- __folio_add_file_rmap(folio, page, HPAGE_PMD_NR, vma, RMAP_LEVEL_PMD);
+ __folio_add_file_rmap(folio, page, HPAGE_PMD_NR, vma, PGTABLE_LEVEL_PMD);
#else
WARN_ON_ONCE(true);
#endif
@@ -1672,7 +1676,7 @@ void folio_add_file_rmap_pud(struct folio *folio, struct page *page,
{
#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && \
defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD)
- __folio_add_file_rmap(folio, page, HPAGE_PUD_NR, vma, RMAP_LEVEL_PUD);
+ __folio_add_file_rmap(folio, page, HPAGE_PUD_NR, vma, PGTABLE_LEVEL_PUD);
#else
WARN_ON_ONCE(true);
#endif
@@ -1680,7 +1684,7 @@ void folio_add_file_rmap_pud(struct folio *folio, struct page *page,
static __always_inline void __folio_remove_rmap(struct folio *folio,
struct page *page, int nr_pages, struct vm_area_struct *vma,
- enum rmap_level level)
+ enum pgtable_level level)
{
atomic_t *mapped = &folio->_nr_pages_mapped;
int last = 0, nr = 0, nr_pmdmapped = 0;
@@ -1689,7 +1693,7 @@ static __always_inline void __folio_remove_rmap(struct folio *folio,
__folio_rmap_sanity_checks(folio, page, nr_pages, level);
switch (level) {
- case RMAP_LEVEL_PTE:
+ case PGTABLE_LEVEL_PTE:
if (!folio_test_large(folio)) {
nr = atomic_add_negative(-1, &folio->_mapcount);
break;
@@ -1719,11 +1723,11 @@ static __always_inline void __folio_remove_rmap(struct folio *folio,
partially_mapped = nr && atomic_read(mapped);
break;
- case RMAP_LEVEL_PMD:
- case RMAP_LEVEL_PUD:
+ case PGTABLE_LEVEL_PMD:
+ case PGTABLE_LEVEL_PUD:
if (IS_ENABLED(CONFIG_NO_PAGE_MAPCOUNT)) {
last = atomic_add_negative(-1, &folio->_entire_mapcount);
- if (level == RMAP_LEVEL_PMD && last)
+ if (level == PGTABLE_LEVEL_PMD && last)
nr_pmdmapped = folio_large_nr_pages(folio);
nr = folio_dec_return_large_mapcount(folio, vma);
if (!nr) {
@@ -1743,7 +1747,7 @@ static __always_inline void __folio_remove_rmap(struct folio *folio,
nr = atomic_sub_return_relaxed(ENTIRELY_MAPPED, mapped);
if (likely(nr < ENTIRELY_MAPPED)) {
nr_pages = folio_large_nr_pages(folio);
- if (level == RMAP_LEVEL_PMD)
+ if (level == PGTABLE_LEVEL_PMD)
nr_pmdmapped = nr_pages;
nr = nr_pages - (nr & FOLIO_PAGES_MAPPED);
/* Raced ahead of another remove and an add? */
@@ -1757,6 +1761,8 @@ static __always_inline void __folio_remove_rmap(struct folio *folio,
partially_mapped = nr && nr < nr_pmdmapped;
break;
+ default:
+ BUILD_BUG();
}
/*
@@ -1796,7 +1802,7 @@ static __always_inline void __folio_remove_rmap(struct folio *folio,
void folio_remove_rmap_ptes(struct folio *folio, struct page *page,
int nr_pages, struct vm_area_struct *vma)
{
- __folio_remove_rmap(folio, page, nr_pages, vma, RMAP_LEVEL_PTE);
+ __folio_remove_rmap(folio, page, nr_pages, vma, PGTABLE_LEVEL_PTE);
}
/**
@@ -1813,7 +1819,7 @@ void folio_remove_rmap_pmd(struct folio *folio, struct page *page,
struct vm_area_struct *vma)
{
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
- __folio_remove_rmap(folio, page, HPAGE_PMD_NR, vma, RMAP_LEVEL_PMD);
+ __folio_remove_rmap(folio, page, HPAGE_PMD_NR, vma, PGTABLE_LEVEL_PMD);
#else
WARN_ON_ONCE(true);
#endif
@@ -1834,7 +1840,7 @@ void folio_remove_rmap_pud(struct folio *folio, struct page *page,
{
#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && \
defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD)
- __folio_remove_rmap(folio, page, HPAGE_PUD_NR, vma, RMAP_LEVEL_PUD);
+ __folio_remove_rmap(folio, page, HPAGE_PUD_NR, vma, PGTABLE_LEVEL_PUD);
#else
WARN_ON_ONCE(true);
#endif
--
2.50.1
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