Re: [PATCH v3 3/5] page_alloc: Introduce zone_movable_limit[] to keep movable limit for nodes

On 12/11/2012 09:20 PM, Simon Jeons wrote:

On Tue, 2012-12-11 at 20:41 +0800, Jianguo Wu wrote:

quoted

On 2012/12/11 20:24, Simon Jeons wrote:

quoted

On Tue, 2012-12-11 at 11:07 +0800, Jianguo Wu wrote:

quoted

On 2012/12/11 10:33, Tang Chen wrote:

quoted

This patch introduces a new array zone_movable_limit[] to store the
ZONE_MOVABLE limit from movablecore_map boot option for all nodes.
The function sanitize_zone_movable_limit() will find out to which
node the ranges in movable_map.map[] belongs, and calculates the
low boundary of ZONE_MOVABLE for each node.

Signed-off-by: Tang Chen <redacted>
Signed-off-by: Jiang Liu <redacted>
Reviewed-by: Wen Congyang <redacted>
Reviewed-by: Lai Jiangshan <redacted>
Tested-by: Lin Feng <redacted>
---
 mm/page_alloc.c |   77 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 77 insertions(+), 0 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 1c91d16..4853619 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c

@@ -206,6 +206,7 @@ static unsigned long __meminitdata arch_zone_highest_possible_pfn[MAX_NR_ZONES];
 static unsigned long __initdata required_kernelcore;
 static unsigned long __initdata required_movablecore;
 static unsigned long __meminitdata zone_movable_pfn[MAX_NUMNODES];
+static unsigned long __meminitdata zone_movable_limit[MAX_NUMNODES];
 
 /* movable_zone is the "real" zone pages in ZONE_MOVABLE are taken from */
 int movable_zone;

@@ -4340,6 +4341,77 @@ static unsigned long __meminit zone_absent_pages_in_node(int nid,
 	return __absent_pages_in_range(nid, zone_start_pfn, zone_end_pfn);
 }
 
+/**
+ * sanitize_zone_movable_limit - Sanitize the zone_movable_limit array.
+ *
+ * zone_movable_limit is initialized as 0. This function will try to get
+ * the first ZONE_MOVABLE pfn of each node from movablecore_map, and
+ * assigne them to zone_movable_limit.
+ * zone_movable_limit[nid] == 0 means no limit for the node.
+ *
+ * Note: Each range is represented as [start_pfn, end_pfn)
+ */
+static void __meminit sanitize_zone_movable_limit(void)
+{
+	int map_pos = 0, i, nid;
+	unsigned long start_pfn, end_pfn;
+
+	if (!movablecore_map.nr_map)
+		return;
+
+	/* Iterate all ranges from minimum to maximum */
+	for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid) {
+		/*
+		 * If we have found lowest pfn of ZONE_MOVABLE of the node
+		 * specified by user, just go on to check next range.
+		 */
+		if (zone_movable_limit[nid])
+			continue;
+
+#ifdef CONFIG_ZONE_DMA
+		/* Skip DMA memory. */
+		if (start_pfn < arch_zone_highest_possible_pfn[ZONE_DMA])
+			start_pfn = arch_zone_highest_possible_pfn[ZONE_DMA];
+#endif
+
+#ifdef CONFIG_ZONE_DMA32
+		/* Skip DMA32 memory. */
+		if (start_pfn < arch_zone_highest_possible_pfn[ZONE_DMA32])
+			start_pfn = arch_zone_highest_possible_pfn[ZONE_DMA32];
+#endif
+
+#ifdef CONFIG_HIGHMEM
+		/* Skip lowmem if ZONE_MOVABLE is highmem. */
+		if (zone_movable_is_highmem() &&

Hi Tang,

I think zone_movable_is_highmem() is not work correctly here.
	sanitize_zone_movable_limit
		zone_movable_is_highmem      <--using movable_zone here
	find_zone_movable_pfns_for_nodes
		find_usable_zone_for_movable <--movable_zone is specified here

Hi Jiangguo and Chen,

- What's the meaning of zone_movable_is_highmem(), does it mean all zone
highmem pages are zone movable pages or ....

Hi Simon,

zone_movable_is_highmem() means whether zone pages in ZONE_MOVABLE are taken from
highmem.

quoted

- dmesg 

quoted

0.000000] Zone ranges:
[    0.000000]   DMA      [mem 0x00010000-0x00ffffff]
[    0.000000]   Normal   [mem 0x01000000-0x373fdfff]
[    0.000000]   HighMem  [mem 0x373fe000-0xb6cfffff]
[    0.000000] Movable zone start for each node
[    0.000000]   Node 0: 0x97800000

Why the start of zone movable is in the range of zone highmem, if all
the pages of zone movable are from zone highmem? If the answer is yes, 

quoted

zone movable and zone highmem are in the equal status or not?

The pages of zone_movable can be taken from zone_movalbe or zone_normal,
if we have highmem, then zone_movable will be taken from zone_highmem,
otherwise zone_movable will be taken from zone_normal.

you can refer to find_usable_zone_for_movable().

Hi Jiangguo,

I have 8G memory, movablecore=5G, but dmesg looks strange, what
happended to me?

Hi Simon,

Is there any other boot parameters for memory taken besides 'movablecore=5G'?

thanks,
linfeng

quoted

[    0.000000] Zone ranges:
[    0.000000]   DMA      [mem 0x00010000-0x00ffffff]
[    0.000000]   Normal   [mem 0x01000000-0x373fdfff]
[    0.000000]   HighMem  [mem 0x373fe000-0xb6cfffff]
[    0.000000] Movable zone start for each node
[    0.000000]   Node 0: 0xb7000000
[    0.000000] Early memory node ranges
[    0.000000]   node   0: [mem 0x00010000-0x0009cfff]
[    0.000000]   node   0: [mem 0x00100000-0x1fffffff]
[    0.000000]   node   0: [mem 0x20200000-0x3fffffff]
[    0.000000]   node   0: [mem 0x40200000-0xb69cbfff]
[    0.000000]   node   0: [mem 0xb6a46000-0xb6a47fff]
[    0.000000]   node   0: [mem 0xb6b1c000-0xb6cfffff]
[    0.000000] On node 0 totalpages: 748095
[    0.000000]   DMA zone: 32 pages used for memmap
[    0.000000]   DMA zone: 0 pages reserved
[    0.000000]   DMA zone: 3949 pages, LIFO batch:0
[    0.000000]   Normal zone: 1736 pages used for memmap
[    0.000000]   Normal zone: 219958 pages, LIFO batch:31
[    0.000000]   HighMem zone: 4083 pages used for memmap
[    0.000000]   HighMem zone: 517569 pages, LIFO batch:31
[    0.000000]   Movable zone: 768 pages, LIFO batch:0

quoted

Thanks,
Jianguo Wu

quoted

quoted

I think Jiang Liu's patch works fine for highmem, please refer to:
http://marc.info/?l=linux-mm&m=135476085816087&w=2

Thanks,
Jianguo Wu

quoted

+		    start_pfn < arch_zone_lowest_possible_pfn[ZONE_HIGHMEM])
+			start_pfn = arch_zone_lowest_possible_pfn[ZONE_HIGHMEM];
+#endif
+
+		if (start_pfn >= end_pfn)
+			continue;
+
+		while (map_pos < movablecore_map.nr_map) {
+			if (end_pfn <= movablecore_map.map[map_pos].start_pfn)
+				break;
+
+			if (start_pfn >= movablecore_map.map[map_pos].end_pfn) {
+				map_pos++;
+				continue;
+			}
+
+			/*
+			 * The start_pfn of ZONE_MOVABLE is either the minimum
+			 * pfn specified by movablecore_map, or 0, which means
+			 * the node has no ZONE_MOVABLE.
+			 */
+			zone_movable_limit[nid] = max(start_pfn,
+					movablecore_map.map[map_pos].start_pfn);
+
+			break;
+		}
+	}
+}
+
 #else /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
 static inline unsigned long __meminit zone_spanned_pages_in_node(int nid,
 					unsigned long zone_type,

@@ -4358,6 +4430,10 @@ static inline unsigned long __meminit zone_absent_pages_in_node(int nid,
 	return zholes_size[zone_type];
 }
 
+static void __meminit sanitize_zone_movable_limit(void)
+{
+}
+
 #endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
 
 static void __meminit calculate_node_totalpages(struct pglist_data *pgdat,

@@ -4923,6 +4999,7 @@ void __init free_area_init_nodes(unsigned long *max_zone_pfn)
 
 	/* Find the PFNs that ZONE_MOVABLE begins at in each node */
 	memset(zone_movable_pfn, 0, sizeof(zone_movable_pfn));
+	sanitize_zone_movable_limit();
 	find_zone_movable_pfns_for_nodes();
 
 	/* Print out the zone ranges */

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