arm64: mremap speedup - enable HAVE_MOVE_PUD

HAVE_MOVE_PUD enables remapping pages at the PUD level if both the source
and destination addresses are PUD-aligned.

With HAVE_MOVE_PUD enabled it can be inferred that there is approximately
a 19x improvement in performance on arm64.  (See data below).

------- Test Results ---------

The following results were obtained using a 5.4 kernel, by remapping a
PUD-aligned, 1GB sized region to a PUD-aligned destination.  The results
from 10 iterations of the test are given below:

Total mremap times for 1GB data on arm64. All times are in nanoseconds.

  Control          HAVE_MOVE_PUD

  1247761          74271
  1219896          46771
  1094792          59687
  1227760          48385
  1043698          76666
  1101771          50365
  1159896          52500
  1143594          75261
  1025833          61354
  1078125          48697

  1134312.6        59395.7    <-- Mean time in nanoseconds

A 1GB mremap completion time drops from ~1.1 milliseconds to ~59
microseconds on arm64.  (~19x speed up).

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Kalesh Singh <[email protected]>
Acked-by: Kirill A. Shutemov <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Aneesh Kumar K.V <[email protected]>
Cc: Anshuman Khandual <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Brian Geffon <[email protected]>
Cc: Christian Brauner <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
Cc: Gavin Shan <[email protected]>
Cc: Hassan Naveed <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jia He <[email protected]>
Cc: John Hubbard <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Krzysztof Kozlowski <[email protected]>
Cc: Lokesh Gidra <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Masahiro Yamada <[email protected]>
Cc: Masami Hiramatsu <[email protected]>
Cc: Mike Rapoport <[email protected]>
Cc: Mina Almasry <[email protected]>
Cc: Minchan Kim <[email protected]>
Cc: Peter Zijlstra (Intel) <[email protected]>
Cc: Ralph Campbell <[email protected]>
Cc: Ram Pai <[email protected]>
Cc: Sami Tolvanen <[email protected]>
Cc: Sandipan Das <[email protected]>
Cc: SeongJae Park <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Steven Price <[email protected]>
Cc: Suren Baghdasaryan <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Zi Yan <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

2 files changed, 2 insertions, 0 deletions

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index a6b5b7ef40ae..15bb857e42e1 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -125,6 +125,7 @@ config ARM64
 	select HANDLE_DOMAIN_IRQ
 	select HARDIRQS_SW_RESEND
 	select HAVE_MOVE_PMD
+	select HAVE_MOVE_PUD
 	select HAVE_PCI
 	select HAVE_ACPI_APEI if (ACPI && EFI)
 	select HAVE_ALIGNED_STRUCT_PAGE if SLUB
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 5628289b9d5e..60ef460b9f53 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -462,6 +462,7 @@ static inline pmd_t pmd_mkdevmap(pmd_t pmd)
 #define pfn_pud(pfn,prot)	__pud(__phys_to_pud_val((phys_addr_t)(pfn) << PAGE_SHIFT) | pgprot_val(prot))
 
 #define set_pmd_at(mm, addr, pmdp, pmd)	set_pte_at(mm, addr, (pte_t *)pmdp, pmd_pte(pmd))
+#define set_pud_at(mm, addr, pudp, pud)	set_pte_at(mm, addr, (pte_t *)pudp, pud_pte(pud))
 
 #define __p4d_to_phys(p4d)	__pte_to_phys(p4d_pte(p4d))
 #define __phys_to_p4d_val(phys)	__phys_to_pte_val(phys)