From: Kalesh Singh <kaleshsingh@google.com>
To: unlisted-recipients:; (no To-header on input)
Cc: surenb@google.com, minchan@google.com, joelaf@google.com,
lokeshgidra@google.com, kaleshsingh@google.com,
kernel-team@android.com,
"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
Shuah Khan <shuah@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Kees Cook <keescook@chromium.org>,
"Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
Sami Tolvanen <samitolvanen@google.com>,
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Josh Poimboeuf <jpoimboe@redhat.com>,
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Hassan Naveed <hnaveed@wavecomp.com>,
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linux-kernel@vger.kernel.org,
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linux-kselftest@vger.kernel.org
Subject: [PATCH v4 2/5] arm64: mremap speedup - Enable HAVE_MOVE_PMD
Date: Wed, 14 Oct 2020 00:53:07 +0000 [thread overview]
Message-ID: <20201014005320.2233162-3-kaleshsingh@google.com> (raw)
In-Reply-To: <20201014005320.2233162-1-kaleshsingh@google.com>
HAVE_MOVE_PMD enables remapping pages at the PMD level if both the
source and destination addresses are PMD-aligned.
HAVE_MOVE_PMD is already enabled on x86. The original patch [1] that
introduced this config did not enable it on arm64 at the time because
of performance issues with flushing the TLB on every PMD move. These
issues have since been addressed in more recent releases with
improvements to the arm64 TLB invalidation and core mmu_gather code as
Will Deacon mentioned in [2].
From the data below, it can be inferred that there is approximately
8x improvement in performance when HAVE_MOVE_PMD is enabled on arm64.
--------- Test Results ----------
The following results were obtained on an arm64 device running a 5.4
kernel, by remapping a PMD-aligned, 1GB sized region to a PMD-aligned
destination. The results from 10 iterations of the test are given below.
All times are in nanoseconds.
Control HAVE_MOVE_PMD
9220833 1247761
9002552 1219896
9254115 1094792
8725885 1227760
9308646 1043698
9001667 1101771
8793385 1159896
8774636 1143594
9553125 1025833
9374010 1078125
9100885.4 1134312.6 <-- Mean Time in nanoseconds
Total mremap time for a 1GB sized PMD-aligned region drops from
~9.1 milliseconds to ~1.1 milliseconds. (~8x speedup).
[1] https://lore.kernel.org/r/20181108181201.88826-3-joelaf@google.com
[2] https://www.mail-archive.com/linuxppc-dev@lists.ozlabs.org/msg140837.html
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: Andrew Morton <akpm@linux-foundation.org>
---
Changes in v4:
- Add Kirill's Acked-by.
arch/arm64/Kconfig | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 4b136e923ccb..434d6791e869 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -123,6 +123,7 @@ config ARM64
select GENERIC_VDSO_TIME_NS
select HANDLE_DOMAIN_IRQ
select HARDIRQS_SW_RESEND
+ select HAVE_MOVE_PMD
select HAVE_PCI
select HAVE_ACPI_APEI if (ACPI && EFI)
select HAVE_ALIGNED_STRUCT_PAGE if SLUB
--
2.28.0.1011.ga647a8990f-goog
next prev parent reply other threads:[~2020-10-14 9:23 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-14 0:53 [PATCH v4 0/5] Speed up mremap on large regions Kalesh Singh
2020-10-14 0:53 ` [PATCH v4 1/5] kselftests: vm: Add mremap tests Kalesh Singh
2020-10-14 19:02 ` Kalesh Singh
2020-10-14 0:53 ` Kalesh Singh [this message]
2020-10-15 10:55 ` [PATCH v4 2/5] arm64: mremap speedup - Enable HAVE_MOVE_PMD Will Deacon
2020-10-14 0:53 ` [PATCH v4 3/5] mm: Speedup mremap on 1GB or larger regions Kalesh Singh
2020-12-17 17:28 ` Guenter Roeck
2020-12-17 18:15 ` Kalesh Singh
2020-10-14 0:53 ` [PATCH v4 4/5] arm64: mremap speedup - Enable HAVE_MOVE_PUD Kalesh Singh
2020-10-14 0:53 ` [PATCH v4 5/5] x86: " Kalesh Singh
2020-10-14 15:53 ` Ingo Molnar
2020-10-15 20:40 ` [PATCH v4 0/5] Speed up mremap on large regions Will Deacon
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