Thread (16 messages) 16 messages, 2 authors, 2021-05-25

[PATCH v6 11/11] powerpc/mm: Enable HAVE_MOVE_PMD support

From: Aneesh Kumar K.V <hidden>
Date: 2021-05-24 09:02:26
Also in: linuxppc-dev
Subsystem: linux for powerpc (32-bit and 64-bit), the rest · Maintainers: Madhavan Srinivasan, Michael Ellerman, Linus Torvalds

mremap HAVE_MOVE_PMD/PUD optimization time comparison for 1GB region:
1GB mremap - Source PTE-aligned, Destination PTE-aligned
  mremap time:      1122062ns
1GB mremap - Source PMD-aligned, Destination PMD-aligned
  mremap time:       522062ns
1GB mremap - Source PUD-aligned, Destination PUD-aligned
  mremap time:       523345ns

There is not much impact with HAVE_MOVE_PUD because the kernel by default
enables USE_SPLIT_PTE_PTLOCKS. That results in the optimized pud move being
disabled.

Signed-off-by: Aneesh Kumar K.V <redacted>
---
 arch/powerpc/platforms/Kconfig.cputype | 2 ++
 1 file changed, 2 insertions(+)
diff --git a/arch/powerpc/platforms/Kconfig.cputype b/arch/powerpc/platforms/Kconfig.cputype
index 3ce907523b1e..2e666e569fdf 100644
--- a/arch/powerpc/platforms/Kconfig.cputype
+++ b/arch/powerpc/platforms/Kconfig.cputype
@@ -97,6 +97,8 @@ config PPC_BOOK3S_64
 	select PPC_HAVE_PMU_SUPPORT
 	select SYS_SUPPORTS_HUGETLBFS
 	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
+	select HAVE_MOVE_PMD
+	select HAVE_MOVE_PUD
 	select ARCH_ENABLE_THP_MIGRATION if TRANSPARENT_HUGEPAGE
 	select ARCH_SUPPORTS_NUMA_BALANCING
 	select IRQ_WORK
-- 
2.31.1

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