[PATCH v4 7/8] mm: Hook up Kconfig options for async page table freeing

[Lu Baolu <baolu.lu@linux.intel.com>]

From: Dave Hansen <dave.hansen@linux.intel.com>

The CONFIG_ASYNC_PGTABLE_FREE option controls whether an architecture
requires asynchronous page table freeing. On x86, this is selected if
IOMMU_SVA is enabled, because both Intel and AMD IOMMU architectures
could potentially cache kernel page table entries in their paging
structure cache, regardless of the permission.

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
 arch/x86/Kconfig | 1 +
 mm/Kconfig       | 3 +++
 2 files changed, 4 insertions(+)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 58d890fe2100..1b2326d81681 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -281,6 +281,7 @@ config X86
 	select HAVE_PCI
 	select HAVE_PERF_REGS
 	select HAVE_PERF_USER_STACK_DUMP
+	select ASYNC_PGTABLE_FREE		if IOMMU_SVA
 	select MMU_GATHER_RCU_TABLE_FREE
 	select MMU_GATHER_MERGE_VMAS
 	select HAVE_POSIX_CPU_TIMERS_TASK_WORK
diff --git a/mm/Kconfig b/mm/Kconfig
index e443fe8cd6cf..1576409cec03 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -920,6 +920,9 @@ config PAGE_MAPCOUNT
 config PGTABLE_HAS_HUGE_LEAVES
 	def_bool TRANSPARENT_HUGEPAGE || HUGETLB_PAGE
 
+config ASYNC_PGTABLE_FREE
+	def_bool n
+
 # TODO: Allow to be enabled without THP
 config ARCH_SUPPORTS_HUGE_PFNMAP
 	def_bool n
-- 
2.43.0