[PATCH v10 0/9] Hyper-V: paravirtualized remote TLB flushing and hypercall improvements

From: Vitaly Kuznetsov
Date: Wed Aug 02 2017 - 12:09:34 EST


Changes since v9:
- Rebase to 4.13-rc3.
- Drop PATCH1 as it was already taken by Greg to char-misc tree. There're no
functional dependencies on this patch so the series can go through a different tree
(and it actually belongs to x86 if I got Ingo's comment right).
- Add in missing void return type in PATCH1 [Colin King, Ingo Molnar, Greg KH]
- A few minor fixes in what is now PATCH7: add pr_fmt, tiny style fix in
hyperv_flush_tlb_others() [Andy Shevchenko]
- Fix "error: implicit declaration of function 'virt_to_phys'" in PATCH2
reported by kbuild test robot (#include <asm/io.h>)
- Add Steven's 'Reviewed-by:' to PATCH9.

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 (9):
x86/hyper-v: include hyperv/ only when CONFIG_HYPERV is set
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 | 272 ++++++++++++++++++++++++++++++++++++
arch/x86/include/asm/mshyperv.h | 147 ++++++++++++++++++-
arch/x86/include/asm/trace/hyperv.h | 40 ++++++
arch/x86/include/uapi/asm/hyperv.h | 17 +++
arch/x86/kernel/cpu/mshyperv.c | 1 +
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 | 54 +------
include/linux/hyperv.h | 17 +--
16 files changed, 533 insertions(+), 174 deletions(-)
create mode 100644 arch/x86/hyperv/mmu.c
create mode 100644 arch/x86/include/asm/trace/hyperv.h

--
2.13.3