linux-kernel - [PATCH RFC 39/39] mm/rmap: rename COMPOUND_MAPPED to ENTIRELY

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Message-ID: <20231204142146.91437-40-david@redhat.com>
Date:   Mon,  4 Dec 2023 15:21:46 +0100
From:   David Hildenbrand <david@...hat.com>
To:     linux-kernel@...r.kernel.org
Cc:     linux-mm@...ck.org, David Hildenbrand <david@...hat.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        "Matthew Wilcox (Oracle)" <willy@...radead.org>,
        Hugh Dickins <hughd@...gle.com>,
        Ryan Roberts <ryan.roberts@....com>,
        Yin Fengwei <fengwei.yin@...el.com>,
        Mike Kravetz <mike.kravetz@...cle.com>,
        Muchun Song <muchun.song@...ux.dev>,
        Peter Xu <peterx@...hat.com>
Subject: [PATCH RFC 39/39] mm/rmap: rename COMPOUND_MAPPED to ENTIRELY_MAPPED

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@...hat.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 cf81272a6b8b6..93c9239b9ebe2 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 b9b630717b9b2..700b230666f87 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 7bb3a174efc8d..a8e3563182103 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1142,7 +1142,7 @@ 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)
@@ -1151,15 +1151,15 @@ static __always_inline unsigned int __folio_add_rmap(struct folio *folio,
 	} else if (mode == 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;
 			}
 		}
@@ -1384,7 +1384,7 @@ 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);
 		nr = folio_nr_pages(folio);
 		__lruvec_stat_mod_folio(folio, NR_ANON_THPS, nr);
 	}
@@ -1467,7 +1467,7 @@ 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)
@@ -1476,15 +1476,15 @@ static __always_inline void __folio_remove_rmap(struct folio *folio,
 	} else if (mode == 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;
 			}
 		}
-- 
2.41.0