Pages used by the kernel cannot be migrated. As a result, hotpluggable
memory used by the kernel cannot be hot-removed. So for memory
hotplug users, the kernel should not use hotpluggable memory.
Since now we have flags in memblock, we introduce a MEMBLK_HOTPLUGGABLE
flag to mark hotpluggable memory. At the early time, we use memblock to
reserve hotpluggable memory, and mark it with MEMBLK_HOTPLUGGABLE flag.
When the system is up, we free these memory with MEMBLK_HOTPLUGGABLE
flag to the buddy, and arrange them into ZONE_MOVABLE. In this way, the
kernel won't be able to use it.
This patch introduces MEMBLK_HOTPLUGGABLE flag, and an API to reserve
memory with MEMBLK_HOTPLUGGABLE flag. This is a preparation for the
coming patches.
Signed-off-by: Tang Chen <tangchen@xxxxxxxxxxxxxx>
---
include/linux/memblock.h | 2 ++
mm/memblock.c | 6 ++++++
2 files changed, 8 insertions(+), 0 deletions(-)
diff --git a/include/linux/memblock.h b/include/linux/memblock.h
index 93f3453..90b49ee 100644
--- a/include/linux/memblock.h
+++ b/include/linux/memblock.h
@@ -21,6 +21,7 @@
/* Definition of memblock flags. */
#define MEMBLK_FLAGS_DEFAULT 0x0 /* default flag */
+#define MEMBLK_HOTPLUGGABLE 0x1 /* hotpluggable region */
struct memblock_region {
phys_addr_t base;
@@ -61,6 +62,7 @@ int memblock_add(phys_addr_t base, phys_addr_t size);
int memblock_remove(phys_addr_t base, phys_addr_t size);
int memblock_free(phys_addr_t base, phys_addr_t size);
int memblock_reserve(phys_addr_t base, phys_addr_t size);
+int memblock_reserve_hotpluggable(phys_addr_t base, phys_addr_t size, int nid);
void memblock_trim_memory(phys_addr_t align);
#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
diff --git a/mm/memblock.c b/mm/memblock.c
index 9e871e9..73fe62d 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -586,6 +586,12 @@ int __init_memblock memblock_reserve(phys_addr_t base, phys_addr_t size)
MEMBLK_FLAGS_DEFAULT);
}
+int __init_memblock memblock_reserve_hotpluggable(phys_addr_t base,
+ phys_addr_t size, int nid)
+{
+ return memblock_reserve_region(base, size, nid, MEMBLK_HOTPLUGGABLE);
+}
+
/**
* __next_free_mem_range - next function for for_each_free_mem_range()
* @idx: pointer to u64 loop variable
--
1.7.1
--
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