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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