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Groups > linux.kernel > #1727660

[PATCH v3 0/2] guard virt_spin_lock() with a static key

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With virt_spin_lock() being guarded by a static key the bare metal case
can be optimized by patching the call away completely. In case a kernel
running as a guest it can decide whether to use paravitualized
spinlocks, the current fallback to the unfair test-and-set scheme, or
to mimic the bare metal behavior.

V3:
- remove test for hypervisor environment from virt_spin_lock(9 as
  suggested by Waiman Long

V2:
- use static key instead of making virt_spin_lock() a pvops function

Juergen Gross (2):
  paravirt/locks: use new static key for controlling call of
    virt_spin_lock()
  paravirt,xen: correct xen_nopvspin case

 arch/x86/include/asm/qspinlock.h     | 11 ++++++++++-
 arch/x86/kernel/paravirt-spinlocks.c |  6 ++++++
 arch/x86/kernel/smpboot.c            |  2 ++
 arch/x86/xen/spinlock.c              |  2 ++
 kernel/locking/qspinlock.c           |  4 ++++
 5 files changed, 24 insertions(+), 1 deletion(-)

-- 
2.12.3

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[PATCH v3 0/2] guard virt_spin_lock() with a static key Juergen Gross <jgross@suse.com> - 2017-09-06 19:40 +0200
  [PATCH v3 2/2] paravirt,xen: correct xen_nopvspin case Juergen Gross <jgross@suse.com> - 2017-09-06 19:40 +0200
  [PATCH v3 1/2] paravirt/locks: use new static key for controlling call of virt_spin_lock() Juergen Gross <jgross@suse.com> - 2017-09-06 19:40 +0200

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