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Subject[PATCH v5 2/5] page_alloc: add movable_memmap kernel parameter
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This patch adds functions to parse movablecore_map boot option. Since the
option could be specified more then once, all the maps will be stored in
the global variable movablecore_map.map array.

And also, we keep the array in monotonic increasing order by start_pfn.
And merge all overlapped ranges.

Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Reviewed-by: Wen Congyang <wency@cn.fujitsu.com>
Tested-by: Lin Feng <linfeng@cn.fujitsu.com>
---
Documentation/kernel-parameters.txt | 17 +++++
include/linux/mm.h | 11 +++
mm/page_alloc.c | 126 +++++++++++++++++++++++++++++++++++
3 files changed, 154 insertions(+), 0 deletions(-)

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 363e348..f02aa4c 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1637,6 +1637,23 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
that the amount of memory usable for all allocations
is not too small.

+ movablecore_map=nn[KMG]@ss[KMG]
+ [KNL,X86,IA-64,PPC] This parameter is similar to
+ memmap except it specifies the memory map of
+ ZONE_MOVABLE.
+ If more areas are all within one node, then from
+ lowest ss to the end of the node will be ZONE_MOVABLE.
+ If an area covers two or more nodes, the area from
+ ss to the end of the 1st node will be ZONE_MOVABLE,
+ and all the rest nodes will only have ZONE_MOVABLE.
+ If memmap is specified at the same time, the
+ movablecore_map will be limited within the memmap
+ areas. If kernelcore or movablecore is also specified,
+ movablecore_map will have higher priority to be
+ satisfied. So the administrator should be careful that
+ the amount of movablecore_map areas are not too large.
+ Otherwise kernel won't have enough memory to start.
+
MTD_Partition= [MTD]
Format: <name>,<region-number>,<size>,<offset>

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 66e2f7c..12f5a09 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1359,6 +1359,17 @@ extern void free_bootmem_with_active_regions(int nid,
unsigned long max_low_pfn);
extern void sparse_memory_present_with_active_regions(int nid);

+#define MOVABLECORE_MAP_MAX MAX_NUMNODES
+struct movablecore_entry {
+ unsigned long start_pfn; /* start pfn of memory segment */
+ unsigned long end_pfn; /* end pfn of memory segment */
+};
+
+struct movablecore_map {
+ int nr_map;
+ struct movablecore_entry map[MOVABLECORE_MAP_MAX];
+};
+
#endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */

#if !defined(CONFIG_HAVE_MEMBLOCK_NODE_MAP) && \
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index df2022f..d1a7a88 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -201,6 +201,9 @@ static unsigned long __meminitdata nr_all_pages;
static unsigned long __meminitdata dma_reserve;

#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
+/* Movable memory ranges, will also be used by memblock subsystem. */
+struct movablecore_map movablecore_map;
+
static unsigned long __meminitdata arch_zone_lowest_possible_pfn[MAX_NR_ZONES];
static unsigned long __meminitdata arch_zone_highest_possible_pfn[MAX_NR_ZONES];
static unsigned long __initdata required_kernelcore;
@@ -5070,6 +5073,129 @@ static int __init cmdline_parse_movablecore(char *p)
early_param("kernelcore", cmdline_parse_kernelcore);
early_param("movablecore", cmdline_parse_movablecore);

+/**
+ * insert_movablecore_map - Insert a memory range in to movablecore_map.map.
+ * @start_pfn: start pfn of the range
+ * @end_pfn: end pfn of the range
+ *
+ * This function will also merge the overlapped ranges, and sort the array
+ * by start_pfn in monotonic increasing order.
+ */
+static void __init insert_movablecore_map(unsigned long start_pfn,
+ unsigned long end_pfn)
+{
+ int pos, overlap;
+
+ /*
+ * pos will be at the 1st overlapped range, or the position
+ * where the element should be inserted.
+ */
+ for (pos = 0; pos < movablecore_map.nr_map; pos++)
+ if (start_pfn <= movablecore_map.map[pos].end_pfn)
+ break;
+
+ /* If there is no overlapped range, just insert the element. */
+ if (pos == movablecore_map.nr_map ||
+ end_pfn < movablecore_map.map[pos].start_pfn) {
+ /*
+ * If pos is not the end of array, we need to move all
+ * the rest elements backward.
+ */
+ if (pos < movablecore_map.nr_map)
+ memmove(&movablecore_map.map[pos+1],
+ &movablecore_map.map[pos],
+ sizeof(struct movablecore_entry) *
+ (movablecore_map.nr_map - pos));
+ movablecore_map.map[pos].start_pfn = start_pfn;
+ movablecore_map.map[pos].end_pfn = end_pfn;
+ movablecore_map.nr_map++;
+ return;
+ }
+
+ /* overlap will be at the last overlapped range */
+ for (overlap = pos + 1; overlap < movablecore_map.nr_map; overlap++)
+ if (end_pfn < movablecore_map.map[overlap].start_pfn)
+ break;
+
+ /*
+ * If there are more ranges overlapped, we need to merge them,
+ * and move the rest elements forward.
+ */
+ overlap--;
+ movablecore_map.map[pos].start_pfn = min(start_pfn,
+ movablecore_map.map[pos].start_pfn);
+ movablecore_map.map[pos].end_pfn = max(end_pfn,
+ movablecore_map.map[overlap].end_pfn);
+
+ if (pos != overlap && overlap + 1 != movablecore_map.nr_map)
+ memmove(&movablecore_map.map[pos+1],
+ &movablecore_map.map[overlap+1],
+ sizeof(struct movablecore_entry) *
+ (movablecore_map.nr_map - overlap - 1));
+
+ movablecore_map.nr_map -= overlap - pos;
+}
+
+/**
+ * movablecore_map_add_region - Add a memory range into movablecore_map.
+ * @start: physical start address of range
+ * @end: physical end address of range
+ *
+ * This function transform the physical address into pfn, and then add the
+ * range into movablecore_map by calling insert_movablecore_map().
+ */
+static void __init movablecore_map_add_region(u64 start, u64 size)
+{
+ unsigned long start_pfn, end_pfn;
+
+ /* In case size == 0 or start + size overflows */
+ if (start + size <= start)
+ return;
+
+ if (movablecore_map.nr_map >= ARRAY_SIZE(movablecore_map.map)) {
+ pr_err("movable_memory_map: too many entries;"
+ " ignoring [mem %#010llx-%#010llx]\n",
+ (unsigned long long) start,
+ (unsigned long long) (start + size - 1));
+ return;
+ }
+
+ start_pfn = PFN_DOWN(start);
+ end_pfn = PFN_UP(start + size);
+ insert_movablecore_map(start_pfn, end_pfn);
+}
+
+/*
+ * movablecore_map=nn[KMG]@ss[KMG] sets the region of memory to be used as
+ * movable memory.
+ */
+static int __init cmdline_parse_movablecore_map(char *p)
+{
+ char *oldp;
+ u64 start_at, mem_size;
+
+ if (!p)
+ goto err;
+
+ oldp = p;
+ mem_size = memparse(p, &p);
+ if (p == oldp)
+ goto err;
+
+ if (*p == '@') {
+ oldp = ++p;
+ start_at = memparse(p, &p);
+ if (p == oldp || *p != '\0')
+ goto err;
+
+ movablecore_map_add_region(start_at, mem_size);
+ return 0;
+ }
+err:
+ return -EINVAL;
+}
+early_param("movablecore_map", cmdline_parse_movablecore_map);
+
#endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */

/**
--
1.7.1


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