The kvm structure is pretty large. A large portion of it is the vcpu
array, which is 4kB on arm64 with 512 vcpu, double that on x86-64. Of
course, hardly anyone runs VMs this big, so this is often a net waste
of memory and cache locality.
A possible approach is to turn the fixed-size array into an xarray,
which results in a net code deletion after a bit of cleanup.
* From v1:
- Rebased on v5.16-rc1
- Dropped the dubious locking on teardown
- Converted kvm_for_each_vcpu() to xa_for_each_range(), together with
an invasive change converting the index to an unsigned long
Marc Zyngier (7):
KVM: Move wiping of the kvm->vcpus array to common code
KVM: mips: Use kvm_get_vcpu() instead of open-coded access
KVM: s390: Use kvm_get_vcpu() instead of open-coded access
KVM: x86: Use kvm_get_vcpu() instead of open-coded access
KVM: Convert the kvm->vcpus array to a xarray
KVM: Use 'unsigned long' as kvm_for_each_vcpu()'s index
KVM: Convert kvm_for_each_vcpu() to using xa_for_each_range()
arch/arm64/kvm/arch_timer.c | 8 ++---
arch/arm64/kvm/arm.c | 16 +++------
arch/arm64/kvm/pmu-emul.c | 2 +-
arch/arm64/kvm/psci.c | 6 ++--
arch/arm64/kvm/reset.c | 2 +-
arch/arm64/kvm/vgic/vgic-init.c | 10 +++---
arch/arm64/kvm/vgic/vgic-kvm-device.c | 2 +-
arch/arm64/kvm/vgic/vgic-mmio-v2.c | 3 +-
arch/arm64/kvm/vgic/vgic-mmio-v3.c | 7 ++--
arch/arm64/kvm/vgic/vgic-v3.c | 4 +--
arch/arm64/kvm/vgic/vgic-v4.c | 5 +--
arch/arm64/kvm/vgic/vgic.c | 2 +-
arch/mips/kvm/loongson_ipi.c | 4 +--
arch/mips/kvm/mips.c | 23 ++-----------
arch/powerpc/kvm/book3s_32_mmu.c | 2 +-
arch/powerpc/kvm/book3s_64_mmu.c | 2 +-
arch/powerpc/kvm/book3s_hv.c | 8 ++---
arch/powerpc/kvm/book3s_pr.c | 2 +-
arch/powerpc/kvm/book3s_xics.c | 6 ++--
arch/powerpc/kvm/book3s_xics.h | 2 +-
arch/powerpc/kvm/book3s_xive.c | 15 +++++----
arch/powerpc/kvm/book3s_xive.h | 4 +--
arch/powerpc/kvm/book3s_xive_native.c | 8 ++---
arch/powerpc/kvm/e500_emulate.c | 2 +-
arch/powerpc/kvm/powerpc.c | 10 +-----
arch/riscv/kvm/vcpu_sbi.c | 2 +-
arch/riscv/kvm/vm.c | 10 +-----
arch/riscv/kvm/vmid.c | 2 +-
arch/s390/kvm/interrupt.c | 2 +-
arch/s390/kvm/kvm-s390.c | 47 ++++++++++-----------------
arch/s390/kvm/kvm-s390.h | 4 +--
arch/x86/kvm/hyperv.c | 7 ++--
arch/x86/kvm/i8254.c | 2 +-
arch/x86/kvm/i8259.c | 5 +--
arch/x86/kvm/ioapic.c | 4 +--
arch/x86/kvm/irq_comm.c | 7 ++--
arch/x86/kvm/kvm_onhyperv.c | 3 +-
arch/x86/kvm/lapic.c | 6 ++--
arch/x86/kvm/svm/avic.c | 2 +-
arch/x86/kvm/svm/sev.c | 3 +-
arch/x86/kvm/vmx/posted_intr.c | 2 +-
arch/x86/kvm/x86.c | 30 +++++++----------
include/linux/kvm_host.h | 17 +++++-----
virt/kvm/kvm_main.c | 41 ++++++++++++++++-------
44 files changed, 158 insertions(+), 193 deletions(-)
--
2.30.2
