search for: paravirt_spinlocks

Il 26/02/2014 16:14, Waiman Long ha scritto: > This patch enables KVM to use the queue spinlock's PV support code > when the PARAVIRT_SPINLOCKS kernel config option is set. However, > PV support for Xen is not ready yet and so the queue spinlock will > still have to be disabled when PARAVIRT_SPINLOCKS config option is > on with Xen. > > Signed-off-by: Waiman Long <Waiman.Long at hp.com> > --- > arch/x86/kernel/...

Il 26/02/2014 16:14, Waiman Long ha scritto: > This patch enables KVM to use the queue spinlock's PV support code > when the PARAVIRT_SPINLOCKS kernel config option is set. However, > PV support for Xen is not ready yet and so the queue spinlock will > still have to be disabled when PARAVIRT_SPINLOCKS config option is > on with Xen. > > Signed-off-by: Waiman Long <Waiman.Long at hp.com> > --- > arch/x86/kernel/...

...empted(long cpu) > return PVOP_CALLEE1(bool, pv_lock_ops.vcpu_is_preempted, cpu); > } > > +static __always_inline bool pv_virt_spin_lock(struct qspinlock *lock) > +{ > + return PVOP_CALLEE1(bool, pv_lock_ops.virt_spin_lock, lock); > +} > + > #endif /* SMP && PARAVIRT_SPINLOCKS */ > > #ifdef CONFIG_X86_32 > diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h > index 19efefc0e27e..928f5e7953a7 100644 > --- a/arch/x86/include/asm/paravirt_types.h > +++ b/arch/x86/include/asm/paravirt_types.h > @@ -319,6 +319,7 @...

...empted(long cpu) > return PVOP_CALLEE1(bool, pv_lock_ops.vcpu_is_preempted, cpu); > } > > +static __always_inline bool pv_virt_spin_lock(struct qspinlock *lock) > +{ > + return PVOP_CALLEE1(bool, pv_lock_ops.virt_spin_lock, lock); > +} > + > #endif /* SMP && PARAVIRT_SPINLOCKS */ > > #ifdef CONFIG_X86_32 > diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h > index 19efefc0e27e..928f5e7953a7 100644 > --- a/arch/x86/include/asm/paravirt_types.h > +++ b/arch/x86/include/asm/paravirt_types.h > @@ -319,6 +319,7 @...

This patch enables KVM to use the queue spinlock's PV support code when the PARAVIRT_SPINLOCKS kernel config option is set. However, PV support for Xen is not ready yet and so the queue spinlock will still have to be disabled when PARAVIRT_SPINLOCKS config option is on with Xen. Signed-off-by: Waiman Long <Waiman.Long at hp.com> --- arch/x86/kernel/kvm.c | 54 ++++++++++++++++++++++...

...pu_is_preempted, cpu); >>> } >>> >>> +static __always_inline bool pv_virt_spin_lock(struct qspinlock *lock) >>> +{ >>> + return PVOP_CALLEE1(bool, pv_lock_ops.virt_spin_lock, lock); >>> +} >>> + >>> #endif /* SMP && PARAVIRT_SPINLOCKS */ >>> >>> #ifdef CONFIG_X86_32 >>> diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h >>> index 19efefc0e27e..928f5e7953a7 100644 >>> --- a/arch/x86/include/asm/paravirt_types.h >>> +++ b/arch/x86/incl...

...pu_is_preempted, cpu); >>> } >>> >>> +static __always_inline bool pv_virt_spin_lock(struct qspinlock *lock) >>> +{ >>> + return PVOP_CALLEE1(bool, pv_lock_ops.virt_spin_lock, lock); >>> +} >>> + >>> #endif /* SMP && PARAVIRT_SPINLOCKS */ >>> >>> #ifdef CONFIG_X86_32 >>> diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h >>> index 19efefc0e27e..928f5e7953a7 100644 >>> --- a/arch/x86/include/asm/paravirt_types.h >>> +++ b/arch/x86/incl...

With virt_spin_lock() being a pvops function 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. Juergen Gross (4): paravirt: add generic _paravirt_false() function paravirt: switch

With virt_spin_lock() being a pvops function 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. Juergen Gross (4): paravirt: add generic _paravirt_false() function paravirt: switch

...VOP_CALLEE1(bool, pv_lock_ops.vcpu_is_preempted, cpu); >> } >> >> +static __always_inline bool pv_virt_spin_lock(struct qspinlock *lock) >> +{ >> + return PVOP_CALLEE1(bool, pv_lock_ops.virt_spin_lock, lock); >> +} >> + >> #endif /* SMP && PARAVIRT_SPINLOCKS */ >> >> #ifdef CONFIG_X86_32 >> diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h >> index 19efefc0e27e..928f5e7953a7 100644 >> --- a/arch/x86/include/asm/paravirt_types.h >> +++ b/arch/x86/include/asm/paravirt_types.h...

...@@ static __always_inline bool pv_vcpu_is_preempted(long cpu) return PVOP_CALLEE1(bool, pv_lock_ops.vcpu_is_preempted, cpu); } +static __always_inline bool pv_virt_spin_lock(struct qspinlock *lock) +{ + return PVOP_CALLEE1(bool, pv_lock_ops.virt_spin_lock, lock); +} + #endif /* SMP && PARAVIRT_SPINLOCKS */ #ifdef CONFIG_X86_32 diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h index 19efefc0e27e..928f5e7953a7 100644 --- a/arch/x86/include/asm/paravirt_types.h +++ b/arch/x86/include/asm/paravirt_types.h @@ -319,6 +319,7 @@ struct pv_lock_ops { void (*kic...

On Wed, Mar 12, 2014 at 02:54:52PM -0400, Waiman Long wrote: > +static inline void arch_spin_lock(struct qspinlock *lock) > +{ > + if (static_key_false(&paravirt_unfairlocks_enabled)) > + queue_spin_lock_unfair(lock); > + else > + queue_spin_lock(lock); > +} So I would have expected something like: if (static_key_false(&paravirt_spinlock)) { while

On Wed, Mar 12, 2014 at 02:54:52PM -0400, Waiman Long wrote: > +static inline void arch_spin_lock(struct qspinlock *lock) > +{ > + if (static_key_false(&paravirt_unfairlocks_enabled)) > + queue_spin_lock_unfair(lock); > + else > + queue_spin_lock(lock); > +} So I would have expected something like: if (static_key_false(&paravirt_spinlock)) { while

....locks b/kernel/Kconfig.locks > index a70fdeb..451e392 100644 > --- a/kernel/Kconfig.locks > +++ b/kernel/Kconfig.locks > @@ -229,4 +229,4 @@ config ARCH_USE_QUEUE_SPINLOCK > > config QUEUE_SPINLOCK > def_bool y if ARCH_USE_QUEUE_SPINLOCK > - depends on SMP && (!PARAVIRT_SPINLOCKS || !XEN) > + depends on SMP If I read this correctly that means you cannot select any more the old ticketlocks? As in, if you select CONFIG_PARAVIRT on X86 it will automatically select ARCH_USE_QUEUE_SPINLOCK which will then enable this by default? Should the 'def_bool' be selectable?...

...onfig.locks =================================================================== --- linux-2.6.orig/kernel/Kconfig.locks +++ linux-2.6/kernel/Kconfig.locks @@ -229,7 +229,7 @@ config ARCH_USE_QUEUE_SPINLOCK config QUEUE_SPINLOCK def_bool y if ARCH_USE_QUEUE_SPINLOCK - depends on SMP && !PARAVIRT_SPINLOCKS + depends on SMP && !(PARAVIRT_SPINLOCKS && XEN) config ARCH_USE_QUEUE_RWLOCK bool

....locks b/kernel/Kconfig.locks > index a70fdeb..451e392 100644 > --- a/kernel/Kconfig.locks > +++ b/kernel/Kconfig.locks > @@ -229,4 +229,4 @@ config ARCH_USE_QUEUE_SPINLOCK > > config QUEUE_SPINLOCK > def_bool y if ARCH_USE_QUEUE_SPINLOCK > - depends on SMP && (!PARAVIRT_SPINLOCKS || !XEN) > + depends on SMP If I read this correctly that means you cannot select any more the old ticketlocks? As in, if you select CONFIG_PARAVIRT on X86 it will automatically select ARCH_USE_QUEUE_SPINLOCK which will then enable this by default? Should the 'def_bool' be selectable?...

There is no need any more for a special treatment of _raw_spin_unlock() regarding inlining compared to the other spinlock functions. Just treat it like all the other spinlock functions. Remove selecting UNINLINE_SPIN_UNLOCK in case of PARAVIRT_SPINLOCKS. Signed-off-by: Juergen Gross <jgross at suse.com> --- arch/x86/Kconfig | 1 - include/linux/spinlock_api_smp.h | 2 +- kernel/Kconfig.locks | 7 ++++--- kernel/Kconfig.preempt | 3 +-- kernel/locking/spinlock.c | 2 +- lib/Kconfig.debug...

...of SPIN_UNLOCK functions again. We further optimize the unlock path by patching the direct call with a "movb $0,%arg1" if we are indeed using the native unlock code. This makes the unlock code almost as fast as the !PARAVIRT case. This significantly lowers the overhead of having CONFIG_PARAVIRT_SPINLOCKS enabled, even for native code. Signed-off-by: Peter Zijlstra (Intel) <peterz at infradead.org> --- arch/x86/Kconfig | 2 - arch/x86/include/asm/paravirt.h | 28 ++++++++++++++++++++- arch/x86/include/asm/paravirt_types.h | 10 +++++++ arch/x86/include/asm/...

...of SPIN_UNLOCK functions again. We further optimize the unlock path by patching the direct call with a "movb $0,%arg1" if we are indeed using the native unlock code. This makes the unlock code almost as fast as the !PARAVIRT case. This significantly lowers the overhead of having CONFIG_PARAVIRT_SPINLOCKS enabled, even for native code. Signed-off-by: Peter Zijlstra (Intel) <peterz at infradead.org> --- arch/x86/Kconfig | 2 - arch/x86/include/asm/paravirt.h | 28 ++++++++++++++++++++- arch/x86/include/asm/paravirt_types.h | 10 +++++++ arch/x86/include/asm/...

...gt;> } >>>> >>>> +static __always_inline bool pv_virt_spin_lock(struct qspinlock *lock) >>>> +{ >>>> + return PVOP_CALLEE1(bool, pv_lock_ops.virt_spin_lock, lock); >>>> +} >>>> + >>>> #endif /* SMP && PARAVIRT_SPINLOCKS */ >>>> >>>> #ifdef CONFIG_X86_32 >>>> diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h >>>> index 19efefc0e27e..928f5e7953a7 100644 >>>> --- a/arch/x86/include/asm/paravirt_types.h >>>...