[RFC v3 4/5] Only set page reserved in the memblock region

[Nathan Zimmer]

Currently we when we initialze each page struct is set as reserved upon
initialization.  This changes to starting with the reserved bit clear and
then only setting the bit in the reserved region.

Signed-off-by: Robin Holt <holt@xxxxxxx>
Signed-off-by: Nathan Zimmer <nzimmer@xxxxxxx>
To: "H. Peter Anvin" <hpa@xxxxxxxxx>
To: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Linux Kernel <linux-kernel@xxxxxxxxxxxxxxx>
Cc: Linux MM <linux-mm@xxxxxxxxx>
Cc: Rob Landley <rob@xxxxxxxxxxx>
Cc: Mike Travis <travis@xxxxxxx>
Cc: Daniel J Blueman <daniel@xxxxxxxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Yinghai Lu <yinghai@xxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxx>
---
 include/linux/mm.h |  2 ++
 mm/nobootmem.c     |  3 +++
 mm/page_alloc.c    | 19 +++++++++++++++----
 3 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index e0c8528..b264a26 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1322,6 +1322,8 @@ static inline void adjust_managed_page_count(struct page *page, long count)
 	totalram_pages += count;
 }
 
+extern void reserve_bootmem_region(unsigned long start, unsigned long end);
+
 /* Free the reserved page into the buddy system, so it gets managed. */
 static inline void __free_reserved_page(struct page *page)
 {
diff --git a/mm/nobootmem.c b/mm/nobootmem.c
index 2159e68..0840af2 100644
--- a/mm/nobootmem.c
+++ b/mm/nobootmem.c
@@ -117,6 +117,9 @@ static unsigned long __init free_low_memory_core_early(void)
 	phys_addr_t start, end, size;
 	u64 i;
 
+	for_each_reserved_mem_region(i, &start, &end)
+		reserve_bootmem_region(start, end);
+
 	for_each_free_mem_range(i, MAX_NUMNODES, &start, &end, NULL)
 		count += __free_memory_core(start, end);
 
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index df3ec13..227bd39 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -697,17 +697,18 @@ static void free_one_page(struct zone *zone, struct page *page, int order,
 	spin_unlock(&zone->lock);
 }
 
-static void __init_single_page(unsigned long pfn, unsigned long zone, int nid)
+static void __init_single_page(unsigned long pfn, unsigned long zone,
+			       int nid, int page_count)
 {
 	struct page *page = pfn_to_page(pfn);
 	struct zone *z = &NODE_DATA(nid)->node_zones[zone];
 
 	set_page_links(page, zone, nid, pfn);
 	mminit_verify_page_links(page, zone, nid, pfn);
-	init_page_count(page);
 	page_mapcount_reset(page);
 	page_nid_reset_last(page);
-	SetPageReserved(page);
+	set_page_count(page, page_count);
+	ClearPageReserved(page);
 
 	/*
 	 * Mark the block movable so that blocks are reserved for
@@ -736,6 +737,16 @@ static void __init_single_page(unsigned long pfn, unsigned long zone, int nid)
 #endif
 }
 
+void reserve_bootmem_region(unsigned long start, unsigned long end)
+{
+	unsigned long start_pfn = PFN_DOWN(start);
+	unsigned long end_pfn = PFN_UP(end);
+
+	for (; start_pfn < end_pfn; start_pfn++)
+		if (pfn_valid(start_pfn))
+			SetPageReserved(pfn_to_page(start_pfn));
+}
+
 static bool free_pages_prepare(struct page *page, unsigned int order)
 {
 	int i;
@@ -4010,7 +4021,7 @@ void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
 			if (!early_pfn_in_nid(pfn, nid))
 				continue;
 		}
-		__init_single_page(pfn, zone, nid);
+		__init_single_page(pfn, zone, nid, 1);
 	}
 }
 
-- 
1.8.2.1

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