Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Matthew Wilcox <willy@infradead.org>
To:     linux-fsdevel@vger.kernel.org
Cc:     "Matthew Wilcox (Oracle)" <willy@infradead.org>,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: [PATCH v6 08/51] mm: Add thp_order
Date:   Wed, 10 Jun 2020 13:13:02 -0700
Message-Id: <20200610201345.13273-9-willy@infradead.org>
In-Reply-To: <20200610201345.13273-1-willy@infradead.org>
References: <20200610201345.13273-1-willy@infradead.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

From: "Matthew Wilcox (Oracle)" <willy@infradead.org>

This function returns the order of a transparent huge page.  It
compiles to 0 if CONFIG_TRANSPARENT_HUGEPAGE is disabled.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 include/linux/huge_mm.h | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index 71f20776b06c..dd19720a8bc2 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -265,6 +265,19 @@ static inline spinlock_t *pud_trans_huge_lock(pud_t *pud,
 	else
 		return NULL;
 }
+
+/**
+ * thp_order - Order of a transparent huge page.
+ * @page: Head page of a transparent huge page.
+ */
+static inline unsigned int thp_order(struct page *page)
+{
+	VM_BUG_ON_PGFLAGS(PageTail(page), page);
+	if (PageHead(page))
+		return HPAGE_PMD_ORDER;
+	return 0;
+}
+
 static inline int hpage_nr_pages(struct page *page)
 {
 	if (unlikely(PageTransHuge(page)))
@@ -324,6 +337,12 @@ 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 unsigned int thp_order(struct page *page)
+{
+	VM_BUG_ON_PGFLAGS(PageTail(page), page);
+	return 0;
+}
+
 static inline int hpage_nr_pages(struct page *page)
 {
 	VM_BUG_ON_PAGE(PageTail(page), page);
-- 
2.26.2