[PATCH v7 00/10] Hyper-V: paravirtualized remote TLB flushing and hypercall improvements

From: Vitaly Kuznetsov
Date: Wed Jun 07 2017 - 07:01:14 EST


Changes since v6:
- Fix a bug in cpumask_to_vp_set() by setting valid_bank_mask right,
add a check for > 64 banks and fall back to HV_FLUSH_ALL_PROCESSORS
[Jork Loeser]
- Drop DEFINE_TRACE() from mmu.c, change tracing magic a bit to
keep things compiling (steal the idea from x86/include/asm/trace/mpx.h)
[Steven Rostedt]

Original description:

Hyper-V supports hypercalls for doing local and remote TLB flushing and
gives its guests hints when using hypercall is preferred. While doing
hypercalls for local TLB flushes is probably not practical (and is not
being suggested by modern Hyper-V versions) remote TLB flush with a
hypercall brings significant improvement.

To test the series I wrote a special 'TLB trasher': on a 16 vCPU guest I
was creating 32 threads which were doing 100000 mmap/munmaps each on some
big file. Here are the results:

Before:
# time ./pthread_mmap ./randfile
real 3m33.118s
user 0m3.698s
sys 3m16.624s

After:
# time ./pthread_mmap ./randfile
real 2m19.920s
user 0m2.662s
sys 2m9.948s

This series brings a number of small improvements along the way: fast
hypercall implementation and using it for event signaling, rep hypercalls
implementation, hyperv tracing subsystem (which only traces the newly added
remote TLB flush for now).

Vitaly Kuznetsov (10):
x86/hyper-v: include hyperv/ only when CONFIG_HYPERV is set
x86/hyper-v: stash the max number of virtual/logical processor
x86/hyper-v: make hv_do_hypercall() inline
x86/hyper-v: fast hypercall implementation
hyper-v: use fast hypercall for HVCALL_SIGNAL_EVENT
x86/hyper-v: implement rep hypercalls
hyper-v: globalize vp_index
x86/hyper-v: use hypercall for remote TLB flush
x86/hyper-v: support extended CPU ranges for TLB flush hypercalls
tracing/hyper-v: trace hyperv_mmu_flush_tlb_others()

MAINTAINERS | 1 +
arch/x86/Kbuild | 2 +-
arch/x86/hyperv/Makefile | 2 +-
arch/x86/hyperv/hv_init.c | 90 ++++++------
arch/x86/hyperv/mmu.c | 267 ++++++++++++++++++++++++++++++++++++
arch/x86/include/asm/mshyperv.h | 148 +++++++++++++++++++-
arch/x86/include/asm/trace/hyperv.h | 38 +++++
arch/x86/include/uapi/asm/hyperv.h | 17 +++
arch/x86/kernel/cpu/mshyperv.c | 13 +-
drivers/hv/channel_mgmt.c | 20 +--
drivers/hv/connection.c | 7 +-
drivers/hv/hv.c | 9 --
drivers/hv/hyperv_vmbus.h | 11 --
drivers/hv/vmbus_drv.c | 17 ---
drivers/pci/host/pci-hyperv.c | 10 +-
include/linux/hyperv.h | 17 +--
16 files changed, 538 insertions(+), 131 deletions(-)
create mode 100644 arch/x86/hyperv/mmu.c
create mode 100644 arch/x86/include/asm/trace/hyperv.h

--
2.9.4