[PATCH v1 39/39] mm/rmap: rename COMPOUND_MAPPED to ENTIRELY_MAPPED

David Hildenbrand
2023-12-11T15:58:56Z

We removed all "bool compound" and RMAP_COMPOUND parameters. Let's
remove the remaining "compound" terminology by making COMPOUND_MAPPED
match the "folio->_entire_mapcount" terminology, renaming it to
ENTIRELY_MAPPED.

ENTIRELY_MAPPED is only used when the whole folio is mapped using a single
page table entry (e.g., a single PMD mapping a PMD-sized THP). For now,
we don't support mapping any THP bigger than that, so ENTIRELY_MAPPED
only applies to PMD-mapped PMD-sized THP only.

Signed-off-by: David Hildenbrand <david@redhat.com>
---
Documentation/mm/transhuge.rst | 2 +-
mm/internal.h | 6 +++---
mm/rmap.c | 18 +++++++++---------
3 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/Documentation/mm/transhuge.rst b/Documentation/mm/transhuge.rst
index cf81272a6b8b..93c9239b9ebe 100644
--- a/Documentation/mm/transhuge.rst
+++ b/Documentation/mm/transhuge.rst
@@ -117,7 +117,7 @@ pages:

- map/unmap of a PMD entry for the whole THP increment/decrement
folio->_entire_mapcount and also increment/decrement
- folio->_nr_pages_mapped by COMPOUND_MAPPED when _entire_mapcount
+ folio->_nr_pages_mapped by ENTIRELY_MAPPED when _entire_mapcount
goes from -1 to 0 or 0 to -1.

- map/unmap of individual pages with PTE entry increment/decrement
diff --git a/mm/internal.h b/mm/internal.h
index 29589bc3f046..188807d2aebc 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -54,12 +54,12 @@ void page_writeback_init(void);

/*
* If a 16GB hugetlb folio were mapped by PTEs of all of its 4kB pages,
- * its nr_pages_mapped would be 0x400000: choose the COMPOUND_MAPPED bit
+ * its nr_pages_mapped would be 0x400000: choose the ENTIRELY_MAPPED bit
* above that range, instead of 2*(PMD_SIZE/PAGE_SIZE). Hugetlb currently
* leaves nr_pages_mapped at 0, but avoid surprise if it participates later.
*/
-#define COMPOUND_MAPPED 0x800000
-#define FOLIO_PAGES_MAPPED (COMPOUND_MAPPED - 1)
+#define ENTIRELY_MAPPED 0x800000
+#define FOLIO_PAGES_MAPPED (ENTIRELY_MAPPED - 1)

/*
* Flags passed to __show_mem() and show_free_areas() to suppress output in
diff --git a/mm/rmap.c b/mm/rmap.c
index 45296739236f..53753834a10d 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1173,7 +1173,7 @@ static __always_inline unsigned int __folio_add_rmap(struct folio *folio,
first = atomic_inc_and_test(&page->_mapcount);
if (first && folio_test_large(folio)) {
first = atomic_inc_return_relaxed(mapped);
- first = (first < COMPOUND_MAPPED);
+ first = (first < ENTIRELY_MAPPED);
}

if (first)
@@ -1183,15 +1183,15 @@ static __always_inline unsigned int __folio_add_rmap(struct folio *folio,
case RMAP_MODE_PMD:
first = atomic_inc_and_test(&folio->_entire_mapcount);
if (first) {
- nr = atomic_add_return_relaxed(COMPOUND_MAPPED, mapped);
- if (likely(nr < COMPOUND_MAPPED + COMPOUND_MAPPED)) {
+ nr = atomic_add_return_relaxed(ENTIRELY_MAPPED, mapped);
+ if (likely(nr < ENTIRELY_MAPPED + ENTIRELY_MAPPED)) {
*nr_pmdmapped = folio_nr_pages(folio);
nr = *nr_pmdmapped - (nr & FOLIO_PAGES_MAPPED);
/* Raced ahead of a remove and another add? */
if (unlikely(nr < 0))
nr = 0;
} else {
- /* Raced ahead of a remove of COMPOUND_MAPPED */
+ /* Raced ahead of a remove of ENTIRELY_MAPPED */
nr = 0;
}
}
@@ -1434,7 +1434,7 @@ void folio_add_new_anon_rmap(struct folio *folio, struct vm_area_struct *vma,
} else {
/* increment count (starts at -1) */
atomic_set(&folio->_entire_mapcount, 0);
- atomic_set(&folio->_nr_pages_mapped, COMPOUND_MAPPED);
+ atomic_set(&folio->_nr_pages_mapped, ENTIRELY_MAPPED);
SetPageAnonExclusive(&folio->page);
__lruvec_stat_mod_folio(folio, NR_ANON_THPS, nr);
}
@@ -1516,7 +1516,7 @@ static __always_inline void __folio_remove_rmap(struct folio *folio,
last = atomic_add_negative(-1, &page->_mapcount);
if (last && folio_test_large(folio)) {
last = atomic_dec_return_relaxed(mapped);
- last = (last < COMPOUND_MAPPED);
+ last = (last < ENTIRELY_MAPPED);
}

if (last)
@@ -1526,15 +1526,15 @@ static __always_inline void __folio_remove_rmap(struct folio *folio,
case RMAP_MODE_PMD:
last = atomic_add_negative(-1, &folio->_entire_mapcount);
if (last) {
- nr = atomic_sub_return_relaxed(COMPOUND_MAPPED, mapped);
- if (likely(nr < COMPOUND_MAPPED)) {
+ nr = atomic_sub_return_relaxed(ENTIRELY_MAPPED, mapped);
+ if (likely(nr < ENTIRELY_MAPPED)) {
nr_pmdmapped = folio_nr_pages(folio);
nr = nr_pmdmapped - (nr & FOLIO_PAGES_MAPPED);
/* Raced ahead of another remove and an add? */
if (unlikely(nr < 0))
nr = 0;
} else {
- /* An add of COMPOUND_MAPPED raced ahead */
+ /* An add of ENTIRELY_MAPPED raced ahead */
nr = 0;
}
}
--
2.43.0