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[076/200] arm64: mremap speedup - enable HAVE_MOVE_PUD

Message ID 20201215030735.fiUldIRrJ%akpm@linux-foundation.org (mailing list archive)
State New, archived
Headers show
Series [001/200] kthread: add kthread_work tracepoints | expand

Commit Message

Andrew Morton Dec. 15, 2020, 3:07 a.m. UTC
From: Kalesh Singh <kaleshsingh@google.com>
Subject: 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/20201014005320.2233162-5-kaleshsingh@google.com
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Geffon <bgeffon@google.com>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Frederic Weisbecker <frederic@kernel.org>
Cc: Gavin Shan <gshan@redhat.com>
Cc: Hassan Naveed <hnaveed@wavecomp.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jia He <justin.he@arm.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Krzysztof Kozlowski <krzk@kernel.org>
Cc: Lokesh Gidra <lokeshgidra@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Minchan Kim <minchan@google.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Ram Pai <linuxram@us.ibm.com>
Cc: Sami Tolvanen <samitolvanen@google.com>
Cc: Sandipan Das <sandipan@linux.ibm.com>
Cc: SeongJae Park <sjpark@amazon.de>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

 arch/arm64/Kconfig               |    1 +
 arch/arm64/include/asm/pgtable.h |    1 +
 2 files changed, 2 insertions(+)
diff mbox series


--- a/arch/arm64/include/asm/pgtable.h~arm64-mremap-speedup-enable-have_move_pud
+++ a/arch/arm64/include/asm/pgtable.h
@@ -462,6 +462,7 @@  static inline pmd_t pmd_mkdevmap(pmd_t p
 #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)
--- a/arch/arm64/Kconfig~arm64-mremap-speedup-enable-have_move_pud
+++ a/arch/arm64/Kconfig
@@ -125,6 +125,7 @@  config ARM64
 	select HAVE_MOVE_PMD
+	select HAVE_MOVE_PUD
 	select HAVE_PCI
 	select HAVE_ACPI_APEI if (ACPI && EFI)