[PATCH v23 8/9] mm: memory_hotplug: disable memmap_on_memory when hugetlb_free_vmemmap enabled

[Muchun Song]

The parameter of memory_hotplug.memmap_on_memory is not compatible with
hugetlb_free_vmemmap. So disable it when hugetlb_free_vmemmap is
enabled.

Signed-off-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Acked-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
---
 Documentation/admin-guide/kernel-parameters.txt | 8 ++++++++
 drivers/acpi/acpi_memhotplug.c                  | 1 +
 mm/memory_hotplug.c                             | 1 +
 3 files changed, 10 insertions(+)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 3cc19cb78b85..8181345e996a 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -1638,6 +1638,10 @@
 			on:  enable the feature
 			off: disable the feature
 
+			This is not compatible with memory_hotplug.memmap_on_memory.
+			If both parameters are enabled, hugetlb_free_vmemmap takes
+			precedence over memory_hotplug.memmap_on_memory.
+
 	hung_task_panic=
 			[KNL] Should the hung task detector generate panics.
 			Format: 0 | 1
@@ -2904,6 +2908,10 @@
 			Note that even when enabled, there are a few cases where
 			the feature is not effective.
 
+			This is not compatible with hugetlb_free_vmemmap. If
+			both parameters are enabled, hugetlb_free_vmemmap takes
+			precedence over memory_hotplug.memmap_on_memory.
+
 	memtest=	[KNL,X86,ARM,PPC,RISCV] Enable memtest
 			Format: <integer>
 			default : 0 <disable>
diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c
index 8cc195c4c861..0d7f595ee441 100644
--- a/drivers/acpi/acpi_memhotplug.c
+++ b/drivers/acpi/acpi_memhotplug.c
@@ -15,6 +15,7 @@
 #include <linux/acpi.h>
 #include <linux/memory.h>
 #include <linux/memory_hotplug.h>
+#include <linux/hugetlb.h>
 
 #include "internal.h"
 
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 16b3a7a1db8c..6512e6f641bb 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1052,6 +1052,7 @@ bool mhp_supports_memmap_on_memory(unsigned long size)
 	 *       populate a single PMD.
 	 */
 	return memmap_on_memory &&
+	       !is_hugetlb_free_vmemmap_enabled() &&
 	       IS_ENABLED(CONFIG_MHP_MEMMAP_ON_MEMORY) &&
 	       size == memory_block_size_bytes() &&
 	       IS_ALIGNED(vmemmap_size, PMD_SIZE) &&
-- 
2.11.0