search for: __queue_spin_unlock

...400, Waiman Long wrote: > @@ -19,13 +19,46 @@ extern struct static_key virt_unfairlocks_enabled; > * that the clearing the lock bit is done ASAP without artificial delay > * due to compiler optimization. > */ > +#ifdef CONFIG_PARAVIRT_SPINLOCKS > +static __always_inline void __queue_spin_unlock(struct qspinlock *lock) > +#else > static inline void queue_spin_unlock(struct qspinlock *lock) > +#endif > { > barrier(); > ACCESS_ONCE(*(u8 *)lock) = 0; > barrier(); > } > > +#ifdef CONFIG_PARAVIRT_SPINLOCKS > +/* > + * The lock byte can have a value...

...400, Waiman Long wrote: > @@ -19,13 +19,46 @@ extern struct static_key virt_unfairlocks_enabled; > * that the clearing the lock bit is done ASAP without artificial delay > * due to compiler optimization. > */ > +#ifdef CONFIG_PARAVIRT_SPINLOCKS > +static __always_inline void __queue_spin_unlock(struct qspinlock *lock) > +#else > static inline void queue_spin_unlock(struct qspinlock *lock) > +#endif > { > barrier(); > ACCESS_ONCE(*(u8 *)lock) = 0; > barrier(); > } > > +#ifdef CONFIG_PARAVIRT_SPINLOCKS > +/* > + * The lock byte can have a value...

...*/ if (likely(cmpxchg(&qlock->lock, _QSPINLOCK_LOCKED, 0) == _QSPINLOCK_LOCKED)) return; else queue_spin_unlock_slowpath(lock); } else { __queue_spin_unlock(lock); } > // pv_kick_node: > if (pv->cpustate != PV_CPU_HALTED) > return; > ACCESS_ONCE(pv->cpustate) = PV_CPU_KICKED; > __queue_kick_cpu(pv->mycpu, PV_KICK_QUEUE_HEAD); > > Waiter ------------------------------------------- &...

...*/ if (likely(cmpxchg(&qlock->lock, _QSPINLOCK_LOCKED, 0) == _QSPINLOCK_LOCKED)) return; else queue_spin_unlock_slowpath(lock); } else { __queue_spin_unlock(lock); } > // pv_kick_node: > if (pv->cpustate != PV_CPU_HALTED) > return; > ACCESS_ONCE(pv->cpustate) = PV_CPU_KICKED; > __queue_kick_cpu(pv->mycpu, PV_KICK_QUEUE_HEAD); > > Waiter ------------------------------------------- &...

...;> @@ -19,13 +19,46 @@ extern struct static_key virt_unfairlocks_enabled; >> * that the clearing the lock bit is done ASAP without artificial delay >> * due to compiler optimization. >> */ >> +#ifdef CONFIG_PARAVIRT_SPINLOCKS >> +static __always_inline void __queue_spin_unlock(struct qspinlock *lock) >> +#else >> static inline void queue_spin_unlock(struct qspinlock *lock) >> +#endif >> { >> barrier(); >> ACCESS_ONCE(*(u8 *)lock) = 0; >> barrier(); >> } >> >> +#ifdef CONFIG_PARAVIRT_SPINLOCKS >...

...0644 --- a/arch/x86/include/asm/qspinlock.h +++ b/arch/x86/include/asm/qspinlock.h @@ -38,7 +38,11 @@ union arch_qspinlock { * that the clearing the lock bit is done ASAP without artificial delay * due to compiler optimization. */ +#ifdef CONFIG_PARAVIRT_SPINLOCKS +static __always_inline void __queue_spin_unlock(struct qspinlock *lock) +#else static inline void queue_spin_unlock(struct qspinlock *lock) +#endif { union arch_qspinlock *qlock = (union arch_qspinlock *)lock; @@ -47,6 +51,37 @@ static inline void queue_spin_unlock(struct qspinlock *lock) barrier(); } +#ifdef CONFIG_PARAVIRT_SPINLOCKS...

...sm/qspinlock.h +++ b/arch/x86/include/asm/qspinlock.h @@ -19,13 +19,46 @@ extern struct static_key virt_unfairlocks_enabled; * that the clearing the lock bit is done ASAP without artificial delay * due to compiler optimization. */ +#ifdef CONFIG_PARAVIRT_SPINLOCKS +static __always_inline void __queue_spin_unlock(struct qspinlock *lock) +#else static inline void queue_spin_unlock(struct qspinlock *lock) +#endif { barrier(); ACCESS_ONCE(*(u8 *)lock) = 0; barrier(); } +#ifdef CONFIG_PARAVIRT_SPINLOCKS +/* + * The lock byte can have a value of _Q_LOCKED_SLOWPATH to indicate + * that it needs to go t...

On 12/03/14 18:54, Waiman Long wrote: > This patch adds para-virtualization support to the queue spinlock in > the same way as was done in the PV ticket lock code. In essence, the > lock waiters will spin for a specified number of times (QSPIN_THRESHOLD > = 2^14) and then halted itself. The queue head waiter will spins > 2*QSPIN_THRESHOLD times before halting itself. When it has

On 12/03/14 18:54, Waiman Long wrote: > This patch adds para-virtualization support to the queue spinlock in > the same way as was done in the PV ticket lock code. In essence, the > lock waiters will spin for a specified number of times (QSPIN_THRESHOLD > = 2^14) and then halted itself. The queue head waiter will spins > 2*QSPIN_THRESHOLD times before halting itself. When it has

v10->v11: - Use a simple test-and-set unfair lock to simplify the code, but performance may suffer a bit for large guest with many CPUs. - Take out Raghavendra KT's test results as the unfair lock changes may render some of his results invalid. - Add PV support without increasing the size of the core queue node structure. - Other minor changes to address some of the

v10->v11: - Use a simple test-and-set unfair lock to simplify the code, but performance may suffer a bit for large guest with many CPUs. - Take out Raghavendra KT's test results as the unfair lock changes may render some of his results invalid. - Add PV support without increasing the size of the core queue node structure. - Other minor changes to address some of the

v5->v6: - Change the optimized 2-task contending code to make it fairer at the expense of a bit of performance. - Add a patch to support unfair queue spinlock for Xen. - Modify the PV qspinlock code to follow what was done in the PV ticketlock. - Add performance data for the unfair lock as well as the PV support code. v4->v5: - Move the optimized 2-task contending code to the

v5->v6: - Change the optimized 2-task contending code to make it fairer at the expense of a bit of performance. - Add a patch to support unfair queue spinlock for Xen. - Modify the PV qspinlock code to follow what was done in the PV ticketlock. - Add performance data for the unfair lock as well as the PV support code. v4->v5: - Move the optimized 2-task contending code to the

v6->v7: - Remove an atomic operation from the 2-task contending code - Shorten the names of some macros - Make the queue waiter to attempt to steal lock when unfair lock is enabled. - Remove lock holder kick from the PV code and fix a race condition - Run the unfair lock & PV code on overcommitted KVM guests to collect performance data. v5->v6: - Change the optimized

v6->v7: - Remove an atomic operation from the 2-task contending code - Shorten the names of some macros - Make the queue waiter to attempt to steal lock when unfair lock is enabled. - Remove lock holder kick from the PV code and fix a race condition - Run the unfair lock & PV code on overcommitted KVM guests to collect performance data. v5->v6: - Change the optimized

v7->v8: - Remove one unneeded atomic operation from the slowpath, thus improving performance. - Simplify some of the codes and add more comments. - Test for X86_FEATURE_HYPERVISOR CPU feature bit to enable/disable unfair lock. - Reduce unfair lock slowpath lock stealing frequency depending on its distance from the queue head. - Add performance data for IvyBridge-EX CPU.

v7->v8: - Remove one unneeded atomic operation from the slowpath, thus improving performance. - Simplify some of the codes and add more comments. - Test for X86_FEATURE_HYPERVISOR CPU feature bit to enable/disable unfair lock. - Reduce unfair lock slowpath lock stealing frequency depending on its distance from the queue head. - Add performance data for IvyBridge-EX CPU.

N.B. Sorry for the duplicate. This patch series were resent as the original one was rejected by the vger.kernel.org list server due to long header. There is no change in content. v7->v8: - Remove one unneeded atomic operation from the slowpath, thus improving performance. - Simplify some of the codes and add more comments. - Test for X86_FEATURE_HYPERVISOR CPU feature bit

N.B. Sorry for the duplicate. This patch series were resent as the original one was rejected by the vger.kernel.org list server due to long header. There is no change in content. v7->v8: - Remove one unneeded atomic operation from the slowpath, thus improving performance. - Simplify some of the codes and add more comments. - Test for X86_FEATURE_HYPERVISOR CPU feature bit

v8->v9: - Integrate PeterZ's version of the queue spinlock patch with some modification: http://lkml.kernel.org/r/20140310154236.038181843 at infradead.org - Break the more complex patches into smaller ones to ease review effort. - Fix a racing condition in the PV qspinlock code. v7->v8: - Remove one unneeded atomic operation from the slowpath, thus improving