Messages in this thread | | | From | Julien Grall <> | Subject | [PATCH v3 00/15] kvm/arm: Align the VMID allocation with the arm64 ASID one | Date | Wed, 24 Jul 2019 17:25:19 +0100 |
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Hi all,
This patch series is moving out the ASID allocator in a separate file in order to re-use it for the VMID. The benefits are: - CPUs are not forced to exit on a roll-over. - Context invalidation is now per-CPU rather than broadcasted.
There are no performance regression on the fastpath for ASID allocation. Actually on the hackbench measurement (300 hackbench) it was .7% faster.
The measurement was made on a Seattle based SoC (8 CPUs), with the number of VMID limited to 4-bit. The test involves running concurrently 40 guests with 2 vCPUs. Each guest will then execute hackbench 5 times before exiting.
The performance difference (on 5.1-rc1) between the current algo and the new one are: - 2.5% less exit from the guest - 22.4% more flush, although they are now local rather than broadcasted - 0.11% faster (just for the record)
The ASID allocator rework to make it generic has been divided in multiple patches to make the review easier.
A branch with the patch based on 5.3-rc1 can be found:
http://xenbits.xen.org/gitweb/?p=people/julieng/linux-arm.git;a=shortlog;h=refs/heads/vmid-rework/v3
For all the changes see in each patch.
Best regards,
Cc: Russell King <linux@armlinux.org.uk>
Julien Grall (15): arm64/mm: Introduce asid_info structure and move asid_generation/asid_map to it arm64/mm: Move active_asids and reserved_asids to asid_info arm64/mm: Move bits to asid_info arm64/mm: Move the variable lock and tlb_flush_pending to asid_info arm64/mm: Remove dependency on MM in new_context arm64/mm: Store the number of asid allocated per context arm64/mm: Introduce NUM_ASIDS arm64/mm: Split asid_inits in 2 parts arm64/mm: Split the function check_and_switch_context in 3 parts arm64/mm: Introduce a callback to flush the local context arm64: Move the ASID allocator code in a separate file arm64/lib: Add an helper to free memory allocated by the ASID allocator arm/kvm: Introduce a new VMID allocator arch/arm64: Introduce a capability to tell whether 16-bit VMID is available kvm/arm: Align the VMID allocation with the arm64 ASID one
arch/arm/include/asm/kvm_asm.h | 2 +- arch/arm/include/asm/kvm_host.h | 5 +- arch/arm/include/asm/kvm_hyp.h | 1 + arch/arm/include/asm/kvm_mmu.h | 3 +- arch/arm/include/asm/lib_asid.h | 79 +++++++++++++++ arch/arm/kvm/Makefile | 1 + arch/arm/kvm/hyp/tlb.c | 8 +- arch/arm64/include/asm/cpucaps.h | 3 +- arch/arm64/include/asm/kvm_asid.h | 8 ++ arch/arm64/include/asm/kvm_asm.h | 2 +- arch/arm64/include/asm/kvm_host.h | 5 +- arch/arm64/include/asm/kvm_mmu.h | 7 +- arch/arm64/include/asm/lib_asid.h | 79 +++++++++++++++ arch/arm64/kernel/cpufeature.c | 9 ++ arch/arm64/kvm/hyp/tlb.c | 10 +- arch/arm64/lib/Makefile | 2 + arch/arm64/lib/asid.c | 190 ++++++++++++++++++++++++++++++++++++ arch/arm64/mm/context.c | 200 +++++--------------------------------- virt/kvm/arm/arm.c | 125 +++++++++--------------- 19 files changed, 458 insertions(+), 281 deletions(-) create mode 100644 arch/arm/include/asm/lib_asid.h create mode 100644 arch/arm64/include/asm/kvm_asid.h create mode 100644 arch/arm64/include/asm/lib_asid.h create mode 100644 arch/arm64/lib/asid.c
-- 2.11.0
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