mm/rmap: remove RMAP_COMPOUND

No longer used, let's remove it and clarify RMAP_NONE/RMAP_EXCLUSIVE a
bit.

Link: https://lkml.kernel.org/r/20231220224504.646757-23-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Yin Fengwei <fengwei.yin@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/include/linux/rmap.h b/include/linux/rmap.h
index fe7b5a8b0e75b338647a8c5c134fb09a938ca054..bf6cb79aa7a0a9c88be69c2d7c68078e02fb1315 100644 (file)
--- a/include/linux/rmap.h
+++ b/include/linux/rmap.h
@@ -177,20 +177,14 @@ struct anon_vma *folio_get_anon_vma(struct folio *folio);
 typedef int __bitwise rmap_t;
 
 /*
- * No special request: if the page is a subpage of a compound page, it is
- * mapped via a PTE. The mapped (sub)page is possibly shared between processes.
+ * No special request: A mapped anonymous (sub)page is possibly shared between
+ * processes.
  */
 #define RMAP_NONE              ((__force rmap_t)0)
 
-/* The (sub)page is exclusive to a single process. */
+/* The anonymous (sub)page is exclusive to a single process. */
 #define RMAP_EXCLUSIVE         ((__force rmap_t)BIT(0))
 
-/*
- * The compound page is not mapped via PTEs, but instead via a single PMD and
- * should be accounted accordingly.
- */
-#define RMAP_COMPOUND          ((__force rmap_t)BIT(1))
-
 /*
  * Internally, we're using an enum to specify the granularity. We make the
  * compiler emit specialized code for each granularity.

diff --git a/mm/rmap.c b/mm/rmap.c
index 87415bbf24022ef7c57cb05dfba986230466f4df..2b386b9f6791c9393f3094b24ee1578543045509 100644 (file)
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -2662,8 +2662,6 @@ void rmap_walk_locked(struct folio *folio, struct rmap_walk_control *rwc)
  * The following two functions are for anonymous (private mapped) hugepages.
  * Unlike common anonymous pages, anonymous hugepages have no accounting code
  * and no lru code, because we handle hugepages differently from common pages.
- *
- * RMAP_COMPOUND is ignored.
  */
 void hugetlb_add_anon_rmap(struct folio *folio, struct vm_area_struct *vma,
                unsigned long address, rmap_t flags)