Since the kernel pages cannot be migrated, if we want a memory device
hotpluggable, we have to set all the memory on it as ZONE_MOVABLE.
This patch adds a boot option movablemem_map=acpi to inform the kernel
to use Hot Pluggable bit in SRAT to determine which memory device is
hotpluggable.
Signed-off-by: Tang Chen <tangchen@xxxxxxxxxxxxxx>
Signed-off-by: Lai Jiangshan <laijs@xxxxxxxxxxxxxx>
Reviewed-by: Wen Congyang <wency@xxxxxxxxxxxxxx>
Tested-by: Lin Feng <linfeng@xxxxxxxxxxxxxx>
---
Documentation/kernel-parameters.txt | 11 +++++++++++
include/linux/mm.h | 12 ++++++++++++
mm/page_alloc.c | 35 +++++++++++++++++++++++++++++++++++
3 files changed, 58 insertions(+), 0 deletions(-)
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 4609e81..e039888 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1649,6 +1649,17 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
that the amount of memory usable for all allocations
is not too small.
+ movablemem_map=acpi
+ [KNL,X86,IA-64,PPC] This parameter is similar to
+ memmap except it specifies the memory map of
+ ZONE_MOVABLE.
+ This option inform the kernel to use Hot Pluggable bit
+ in flags from SRAT from ACPI BIOS to determine which
+ memory devices could be hotplugged. The corresponding
+ memory ranges will be set as ZONE_MOVABLE.
+ NOTE: Whatever node the kernel resides in will always
+ be un-hotpluggable.
+
MTD_Partition= [MTD]
Format: <name>,<region-number>,<size>,<offset>
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 1c79b10..52c3558 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1332,6 +1332,18 @@ 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 MOVABLEMEM_MAP_MAX MAX_NUMNODES
+struct movablemem_entry {
+ unsigned long start_pfn; /* start pfn of memory segment */
+ unsigned long end_pfn; /* end pfn of memory segment (exclusive) */
+};
+
+struct movablemem_map {
+ bool acpi;
+ int nr_map;
+ struct movablemem_entry map[MOVABLEMEM_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 f368db4..475fd8b 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -202,6 +202,12 @@ 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 movablemem_map movablemem_map = {
+ .acpi = false,
+ .nr_map = 0,
+};
+
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;
@@ -5061,6 +5067,35 @@ static int __init cmdline_parse_movablecore(char *p)
early_param("kernelcore", cmdline_parse_kernelcore);
early_param("movablecore", cmdline_parse_movablecore);
+/**
+ * cmdline_parse_movablemem_map - Parse boot option movablemem_map.
+ * @p: The boot option of the following format:
+ * movablemem_map=acpi
+ *
+ * This option inform the kernel to use Hot Pluggable bit in SRAT to determine
+ * which memory device is hotpluggable, and set the memory on it as movable.
+ *
+ * Return: 0 on success or -EINVAL on failure.
+ */
+static int __init cmdline_parse_movablemem_map(char *p)
+{
+ if (!p || strcmp(p, "acpi"))
+ goto err;
+
+ movablemem_map.acpi = true;
+
+ if (movablemem_map.nr_map) {
+ memset(movablemem_map.map, 0,
+ sizeof(struct movablemem_entry) * movablemem_map.nr_map);
+ }
+
+ return 0;
+
+err:
+ return -EINVAL;
+}
+early_param("movablemem_map", cmdline_parse_movablemem_map);
+
#endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
/**
--
1.7.1
--
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