[PATCH v2, part2 01/10] mm: introduce free_highmem_page() helper to free highmem pages into buddy system

[Jiang Liu <liuj97@gmail.com>]

Introduce helper function free_highmem_page(), which will be used by
architectures with HIGHMEM enabled to free highmem pages into the buddy
system.

Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michel Lespinasse <walken@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org
Cc: Russell King <linux@arm.linux.org.uk>
Cc: David Howells <dhowells@redhat.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: David Daney <david.daney@cavium.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: "H. Peter Anvin" <hpa@zytor.com>
---
 include/linux/mm.h |    7 +++++++
 mm/page_alloc.c    |    9 +++++++++
 2 files changed, 16 insertions(+)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index d75c14b..f2fb750 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1303,6 +1303,13 @@ extern void free_initmem(void);
  */
 extern unsigned long free_reserved_area(unsigned long start, unsigned long end,
 					int poison, char *s);
+#ifdef	CONFIG_HIGHMEM
+/*
+ * Free a highmem page into the buddy system, adjusting totalhigh_pages
+ * and totalram_pages.
+ */
+extern void free_highmem_page(struct page *page);
+#endif
 
 static inline void adjust_managed_page_count(struct page *page, long count)
 {
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 0fadb09..37bc8ab 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -5133,6 +5133,15 @@ unsigned long free_reserved_area(unsigned long start, unsigned long end,
 	return pages;
 }
 
+#ifdef	CONFIG_HIGHMEM
+void free_highmem_page(struct page *page)
+{
+	__free_reserved_page(page);
+	totalram_pages++;
+	totalhigh_pages++;
+}
+#endif
+
 /**
  * set_dma_reserve - set the specified number of pages reserved in the first zone
  * @new_dma_reserve: The number of pages to mark reserved
-- 
1.7.9.5

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