Optimizing HugeTLB vmemmap pages is not compatible with allocating memmap on
hot added memory. If "hugetlb_free_vmemmap=on" and
memory_hotplug.memmap_on_memory" are both passed on the kernel command line,
optimizing hugetlb pages takes precedence. However, the global variable
memmap_on_memory will still be set to 1, even though we will not try to
allocate memmap on hot added memory.
Also introduce mhp_memmap_on_memory() helper to move the definition of
"memmap_on_memory" to the scope of CONFIG_MHP_MEMMAP_ON_MEMORY. In the
next patch, mhp_memmap_on_memory() will also be exported to be used in
hugetlb_vmemmap.c.
Signed-off-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Acked-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
---
mm/memory_hotplug.c | 32 ++++++++++++++++++++++++++------
1 file changed, 26 insertions(+), 6 deletions(-)
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 111684878fd9..a6101ae402f9 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -42,14 +42,36 @@
#include "internal.h"
#include "shuffle.h"
+#ifdef CONFIG_MHP_MEMMAP_ON_MEMORY
+static int memmap_on_memory_set(const char *val, const struct kernel_param *kp)
+{
+ if (hugetlb_optimize_vmemmap_enabled())
+ return 0;
+ return param_set_bool(val, kp);
+}
+
+static const struct kernel_param_ops memmap_on_memory_ops = {
+ .flags = KERNEL_PARAM_OPS_FL_NOARG,
+ .set = memmap_on_memory_set,
+ .get = param_get_bool,
+};
/*
* memory_hotplug.memmap_on_memory parameter
*/
static bool memmap_on_memory __ro_after_init;
-#ifdef CONFIG_MHP_MEMMAP_ON_MEMORY
-module_param(memmap_on_memory, bool, 0444);
+module_param_cb(memmap_on_memory, &memmap_on_memory_ops, &memmap_on_memory, 0444);
MODULE_PARM_DESC(memmap_on_memory, "Enable memmap on memory for memory hotplug");
+
+static inline bool mhp_memmap_on_memory(void)
+{
+ return memmap_on_memory;
+}
+#else
+static inline bool mhp_memmap_on_memory(void)
+{
+ return false;
+}
#endif
enum {
@@ -1263,9 +1285,7 @@ bool mhp_supports_memmap_on_memory(unsigned long size)
* altmap as an alternative source of memory, and we do not exactly
* populate a single PMD.
*/
- return memmap_on_memory &&
- !hugetlb_optimize_vmemmap_enabled() &&
- IS_ENABLED(CONFIG_MHP_MEMMAP_ON_MEMORY) &&
+ return mhp_memmap_on_memory() &&
size == memory_block_size_bytes() &&
IS_ALIGNED(vmemmap_size, PMD_SIZE) &&
IS_ALIGNED(remaining_size, (pageblock_nr_pages << PAGE_SHIFT));
@@ -2083,7 +2103,7 @@ static int __ref try_remove_memory(u64 start, u64 size)
* We only support removing memory added with MHP_MEMMAP_ON_MEMORY in
* the same granularity it was added - a single memory block.
*/
- if (memmap_on_memory) {
+ if (mhp_memmap_on_memory()) {
nr_vmemmap_pages = walk_memory_blocks(start, size, NULL,
get_nr_vmemmap_pages_cb);
if (nr_vmemmap_pages) {
--
2.11.0
