[PATCH v4 00/10] Hyper-V: praravirtualized remote TLB flushing and hypercall improvements

Vitaly Kuznetsov
2017-05-24T12:04:12Z

Changes since v3:
- Force a stack frame in hv_do_hypercall()/hv_do_fast_hypercall8()
[Andy Lutomirski] (Patches 3,4). K. Y., I'm keeping your Acked-by and
Tested-by tags on these patches as I think the adjustment is minor.
I smoke tested both i586 and x86_64 builds and no issues were noticed.

There is a discussion if this need to go through char-misc or x86 tree. The
majority of the stuff in the series is Hyper-V related so char-misc looks
appropriate but Andy noticed that we're clashing with his PCID series so
it may make sense to have everything in x86.

Original descriptions:

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 | 4 +-
arch/x86/hyperv/Makefile | 2 +-
arch/x86/hyperv/hv_init.c | 90 ++++++------
arch/x86/hyperv/mmu.c | 270 ++++++++++++++++++++++++++++++++++++
arch/x86/include/asm/mshyperv.h | 152 +++++++++++++++++++-
arch/x86/include/asm/trace/hyperv.h | 34 +++++
arch/x86/include/uapi/asm/hyperv.h | 36 +++++
arch/x86/kernel/cpu/mshyperv.c | 14 +-
drivers/hv/channel_mgmt.c | 22 ++-
drivers/hv/connection.c | 8 +-
drivers/hv/hv.c | 9 --
drivers/hv/hyperv_vmbus.h | 11 --
drivers/hv/vmbus_drv.c | 17 ---
drivers/pci/host/pci-hyperv.c | 4 +-
include/linux/hyperv.h | 21 ++-
16 files changed, 571 insertions(+), 124 deletions(-)
create mode 100644 arch/x86/hyperv/mmu.c
create mode 100644 arch/x86/include/asm/trace/hyperv.h

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2.9.4