This is like compound_head() but compiles away when
CONFIG_TRANSPARENT_HUGEPAGE is not enabled.
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
---
include/linux/huge_mm.h | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index dcdfd21763a3..bd13e9ac3437 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -266,6 +266,15 @@ static inline spinlock_t *pud_trans_huge_lock(pud_t *pud,
return NULL;
}
+/**
+ * thp_head - Head page of a transparent huge page.
+ * @page: Any page (tail, head or regular) found in the page cache.
+ */
+static inline struct page *thp_head(struct page *page)
+{
+ return compound_head(page);
+}
+
/**
* thp_order - Order of a transparent huge page.
* @page: Head page of a transparent huge page.
@@ -342,6 +351,12 @@ static inline struct list_head *page_deferred_list(struct page *page)
#define HPAGE_PUD_MASK ({ BUILD_BUG(); 0; })
#define HPAGE_PUD_SIZE ({ BUILD_BUG(); 0; })
+static inline struct page *thp_head(struct page *page)
+{
+ VM_BUG_ON_PGFLAGS(PageTail(page), page);
+ return page;
+}
+
static inline unsigned int thp_order(struct page *page)
{
VM_BUG_ON_PGFLAGS(PageTail(page), page);
--
2.27.0
