mirror of
https://github.com/Ysurac/openmptcprouter.git
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123 lines
3.9 KiB
Diff
123 lines
3.9 KiB
Diff
From d0637c505f8a1d8c4088642f1f3e9e3b22da14f6 Mon Sep 17 00:00:00 2001
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From: Barry Song <v-songbaohua@oppo.com>
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Date: Wed, 20 Jul 2022 21:37:37 +1200
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Subject: [PATCH] arm64: enable THP_SWAP for arm64
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THP_SWAP has been proven to improve the swap throughput significantly
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on x86_64 according to commit bd4c82c22c367e ("mm, THP, swap: delay
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splitting THP after swapped out").
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As long as arm64 uses 4K page size, it is quite similar with x86_64
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by having 2MB PMD THP. THP_SWAP is architecture-independent, thus,
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enabling it on arm64 will benefit arm64 as well.
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A corner case is that MTE has an assumption that only base pages
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can be swapped. We won't enable THP_SWAP for ARM64 hardware with
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MTE support until MTE is reworked to coexist with THP_SWAP.
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A micro-benchmark is written to measure thp swapout throughput as
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below,
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unsigned long long tv_to_ms(struct timeval tv)
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{
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return tv.tv_sec * 1000 + tv.tv_usec / 1000;
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}
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main()
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{
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struct timeval tv_b, tv_e;;
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#define SIZE 400*1024*1024
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volatile void *p = mmap(NULL, SIZE, PROT_READ | PROT_WRITE,
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MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
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if (!p) {
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perror("fail to get memory");
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exit(-1);
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}
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madvise(p, SIZE, MADV_HUGEPAGE);
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memset(p, 0x11, SIZE); /* write to get mem */
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gettimeofday(&tv_b, NULL);
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madvise(p, SIZE, MADV_PAGEOUT);
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gettimeofday(&tv_e, NULL);
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printf("swp out bandwidth: %ld bytes/ms\n",
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SIZE/(tv_to_ms(tv_e) - tv_to_ms(tv_b)));
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}
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Testing is done on rk3568 64bit Quad Core Cortex-A55 platform -
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ROCK 3A.
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thp swp throughput w/o patch: 2734bytes/ms (mean of 10 tests)
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thp swp throughput w/ patch: 3331bytes/ms (mean of 10 tests)
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Cc: "Huang, Ying" <ying.huang@intel.com>
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Cc: Minchan Kim <minchan@kernel.org>
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Cc: Johannes Weiner <hannes@cmpxchg.org>
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Cc: Hugh Dickins <hughd@google.com>
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Cc: Andrea Arcangeli <aarcange@redhat.com>
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Cc: Steven Price <steven.price@arm.com>
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Cc: Yang Shi <shy828301@gmail.com>
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Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
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Signed-off-by: Barry Song <v-songbaohua@oppo.com>
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Link: https://lore.kernel.org/r/20220720093737.133375-1-21cnbao@gmail.com
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Signed-off-by: Will Deacon <will@kernel.org>
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---
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arch/arm64/Kconfig | 1 +
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arch/arm64/include/asm/pgtable.h | 6 ++++++
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include/linux/huge_mm.h | 12 ++++++++++++
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mm/swap_slots.c | 2 +-
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4 files changed, 20 insertions(+), 1 deletion(-)
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--- a/arch/arm64/Kconfig
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+++ b/arch/arm64/Kconfig
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@@ -95,6 +95,7 @@ config ARM64
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select ARCH_WANT_HUGE_PMD_SHARE if ARM64_4K_PAGES || (ARM64_16K_PAGES && !ARM64_VA_BITS_36)
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select ARCH_WANT_LD_ORPHAN_WARN
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select ARCH_WANTS_NO_INSTR
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+ select ARCH_WANTS_THP_SWAP if ARM64_4K_PAGES
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select ARCH_HAS_UBSAN_SANITIZE_ALL
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select ARM_AMBA
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select ARM_ARCH_TIMER
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--- a/arch/arm64/include/asm/pgtable.h
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+++ b/arch/arm64/include/asm/pgtable.h
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@@ -44,6 +44,12 @@
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__flush_tlb_range(vma, addr, end, PUD_SIZE, false, 1)
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#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
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+static inline bool arch_thp_swp_supported(void)
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+{
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+ return !system_supports_mte();
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+}
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+#define arch_thp_swp_supported arch_thp_swp_supported
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+
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/*
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* Outside of a few very special situations (e.g. hibernation), we always
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* use broadcast TLB invalidation instructions, therefore a spurious page
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--- a/include/linux/huge_mm.h
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+++ b/include/linux/huge_mm.h
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@@ -495,4 +495,16 @@ static inline unsigned long thp_size(str
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return PAGE_SIZE << thp_order(page);
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}
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+/*
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+ * archs that select ARCH_WANTS_THP_SWAP but don't support THP_SWP due to
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+ * limitations in the implementation like arm64 MTE can override this to
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+ * false
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+ */
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+#ifndef arch_thp_swp_supported
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+static inline bool arch_thp_swp_supported(void)
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+{
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+ return true;
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+}
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+#endif
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+
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#endif /* _LINUX_HUGE_MM_H */
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--- a/mm/swap_slots.c
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+++ b/mm/swap_slots.c
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@@ -308,7 +308,7 @@ swp_entry_t get_swap_page(struct page *p
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entry.val = 0;
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if (PageTransHuge(page)) {
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- if (IS_ENABLED(CONFIG_THP_SWAP))
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+ if (IS_ENABLED(CONFIG_THP_SWAP) && arch_thp_swp_supported())
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get_swap_pages(1, &entry, HPAGE_PMD_NR);
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goto out;
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}
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