[PATCH RFC 02/12] mm: add config option and per-NUMA node VMS support

[<artem.kuzin@huawei.com>]

From: Artem Kuzin <artem.kuzin@huawei.com>

Co-developed-by: Nikita Panov <nikita.panov@huawei-partners.com>
Signed-off-by: Nikita Panov <nikita.panov@huawei-partners.com>
Co-developed-by: Alexander Grubnikov <alexander.grubnikov@huawei.com>
Signed-off-by: Alexander Grubnikov <alexander.grubnikov@huawei.com>
Signed-off-by: Artem Kuzin <artem.kuzin@huawei.com>
---
 include/linux/mm_types.h | 11 ++++++++++-
 mm/Kconfig               | 10 ++++++++++
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 7d30dc4ff0ff..1fafb8425994 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -22,6 +22,8 @@
 
 #include <asm/mmu.h>
 
+#include <linux/numa.h>
+
 #ifndef AT_VECTOR_SIZE_ARCH
 #define AT_VECTOR_SIZE_ARCH 0
 #endif
@@ -626,7 +628,14 @@ struct mm_struct {
 		unsigned long mmap_compat_legacy_base;
 #endif
 		unsigned long task_size;	/* size of task vm space */
-		pgd_t * pgd;
+#ifndef CONFIG_KERNEL_REPLICATION
+		pgd_t *pgd;
+#else
+		union {
+			pgd_t *pgd;
+			pgd_t *pgd_numa[MAX_NUMNODES];
+		};
+#endif
 
 #ifdef CONFIG_MEMBARRIER
 		/**
diff --git a/mm/Kconfig b/mm/Kconfig
index 09130434e30d..5fe5b3ba7f99 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -1236,6 +1236,16 @@ config LOCK_MM_AND_FIND_VMA
 	bool
 	depends on !STACK_GROWSUP
 
+config KERNEL_REPLICATION
+	bool "Enable kernel text and ro-data replication between NUMA nodes"
+	default n
+	depends on (X86_64 && !(KASAN && X86_5LEVEL)) && MMU && NUMA && !MAXSMP
+
+	help
+	  Creates per-NUMA node replicas of kernel text and rodata sections.
+	  Page tables are replicated partially, according to replicated kernel memory range.
+	  If unsure, say "n".
+
 source "mm/damon/Kconfig"
 
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2.34.1