mm: hugetlb_vmemmap: cleanup hugetlb_free_vmemmap_enabled*

The word of "free" is not expressive enough to express the feature of
optimizing vmemmap pages associated with each HugeTLB, rename this keywork
to "optimize".  In this patch , cheanup the static key and
hugetlb_free_vmemmap_enabled() to make code more expressive.

Link: https://lkml.kernel.org/r/20220404074652.68024-3-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

arch/arm64/mm/flush.c

@@ -86,7 +86,7 @@ void flush_dcache_page(struct page *page)
 	 * is reused (more details can refer to the comments above
 	 * page_fixed_fake_head()).
 	 */
-	if (hugetlb_free_vmemmap_enabled() && PageHuge(page))
+	if (hugetlb_optimize_vmemmap_enabled() && PageHuge(page))
 		page = compound_head(page);
 
 	if (test_bit(PG_dcache_clean, &page->flags))

include/linux/page-flags.h

@@ -192,16 +192,16 @@ enum pageflags {
 
 #ifdef CONFIG_HUGETLB_PAGE_FREE_VMEMMAP
 DECLARE_STATIC_KEY_MAYBE(CONFIG_HUGETLB_PAGE_FREE_VMEMMAP_DEFAULT_ON,
-			 hugetlb_free_vmemmap_enabled_key);
+			 hugetlb_optimize_vmemmap_key);
 
-static __always_inline bool hugetlb_free_vmemmap_enabled(void)
+static __always_inline bool hugetlb_optimize_vmemmap_enabled(void)
 {
 	return static_branch_maybe(CONFIG_HUGETLB_PAGE_FREE_VMEMMAP_DEFAULT_ON,
-				   &hugetlb_free_vmemmap_enabled_key);
+				   &hugetlb_optimize_vmemmap_key);
 }
 
 /*
- * If the feature of freeing some vmemmap pages associated with each HugeTLB
+ * If the feature of optimizing vmemmap pages associated with each HugeTLB
  * page is enabled, the head vmemmap page frame is reused and all of the tail
  * vmemmap addresses map to the head vmemmap page frame (furture details can
  * refer to the figure at the head of the mm/hugetlb_vmemmap.c).  In other
@@ -218,7 +218,7 @@ static __always_inline bool hugetlb_free_vmemmap_enabled(void)
  */
 static __always_inline const struct page *page_fixed_fake_head(const struct page *page)
 {
-	if (!hugetlb_free_vmemmap_enabled())
+	if (!hugetlb_optimize_vmemmap_enabled())
 		return page;
 
 	/*
@@ -247,7 +247,7 @@ static inline const struct page *page_fixed_fake_head(const struct page *page)
 	return page;
 }
 
-static inline bool hugetlb_free_vmemmap_enabled(void)
+static inline bool hugetlb_optimize_vmemmap_enabled(void)
 {
 	return false;
 }

mm/hugetlb_vmemmap.c

@@ -189,8 +189,8 @@
 #define RESERVE_VMEMMAP_SIZE		(RESERVE_VMEMMAP_NR << PAGE_SHIFT)
 
 DEFINE_STATIC_KEY_MAYBE(CONFIG_HUGETLB_PAGE_FREE_VMEMMAP_DEFAULT_ON,
-			hugetlb_free_vmemmap_enabled_key);
-EXPORT_SYMBOL(hugetlb_free_vmemmap_enabled_key);
+			hugetlb_optimize_vmemmap_key);
+EXPORT_SYMBOL(hugetlb_optimize_vmemmap_key);
 
 static int __init hugetlb_vmemmap_early_param(char *buf)
 {
@@ -204,9 +204,9 @@ static int __init hugetlb_vmemmap_early_param(char *buf)
 		return -EINVAL;
 
 	if (!strcmp(buf, "on"))
-		static_branch_enable(&hugetlb_free_vmemmap_enabled_key);
+		static_branch_enable(&hugetlb_optimize_vmemmap_key);
 	else if (!strcmp(buf, "off"))
-		static_branch_disable(&hugetlb_free_vmemmap_enabled_key);
+		static_branch_disable(&hugetlb_optimize_vmemmap_key);
 	else
 		return -EINVAL;
 
@@ -282,7 +282,7 @@ void __init hugetlb_vmemmap_init(struct hstate *h)
 	BUILD_BUG_ON(__NR_USED_SUBPAGE >=
 		     RESERVE_VMEMMAP_SIZE / sizeof(struct page));
 
-	if (!hugetlb_free_vmemmap_enabled())
+	if (!hugetlb_optimize_vmemmap_enabled())
 		return;
 
 	vmemmap_pages = (nr_pages * sizeof(struct page)) >> PAGE_SHIFT;

mm/memory_hotplug.c

@@ -1289,7 +1289,7 @@ bool mhp_supports_memmap_on_memory(unsigned long size)
 	 *       populate a single PMD.
 	 */
 	return memmap_on_memory &&
-	       !hugetlb_free_vmemmap_enabled() &&
+	       !hugetlb_optimize_vmemmap_enabled() &&
 	       IS_ENABLED(CONFIG_MHP_MEMMAP_ON_MEMORY) &&
 	       size == memory_block_size_bytes() &&
 	       IS_ALIGNED(vmemmap_size, PMD_SIZE) &&