search for: __queue_hibernate

...enum fixed_addresses */ idx, } #if defined(CONFIG_SMP) && defined(CONFIG_PARAVIRT_SPINLOCKS) +#ifdef CONFIG_QUEUE_SPINLOCK +static __always_inline void __queue_kick_cpu(int cpu, enum pv_kick_type type) +{ + PVOP_VCALL2(pv_lock_ops.kick_cpu, cpu, type); +} +static __always_inline void __queue_hibernate(void) +{ + PVOP_VCALL0(pv_lock_ops.hibernate); +} +#else static __always_inline void __ticket_lock_spinning(struct arch_spinlock *lock, __ticket_t ticket) { @@ -723,7 +733,7 @@ static __always_inline void __ticket_unlock_kick(struct arch_spinlock *lock, { PVOP_VCALL2(pv_lock_ops.unlock...

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

...CESS_ONCE(pv->cpustate) = PV_CPU_HALTED; lockval = cmpxchg(&qlock->lock, _QSPINLOCK_LOCKED, _QSPINLOCK_LOCKED_SLOWPATH); if (lockval == 0) { /* * Can exit now as the lock is free */ ACCESS_ONCE(pv->cpustate) = PV_CPU_ACTIVE; *count = 0; return; } __queue_hibernate(); Nothing protects from writing qlock->lock before pv->cpustate is read, leading to this: Lock holder Waiter --------------------------------------------------------------- read pv->cpustate (it is PV_CPU_ACTIVE) pv->cpustate = PV_CPU_HALTED lockval = cmpxchg(...)...

...QSPINLOCK_LOCKED_SLOWPATH); > if (lockval == 0) { > /* > * Can exit now as the lock is free > */ > ACCESS_ONCE(pv->cpustate) = PV_CPU_ACTIVE; > *count = 0; > return; > } > __queue_hibernate(); > > Nothing protects from writing qlock->lock before pv->cpustate is read, > leading to this: > > Lock holder Waiter > --------------------------------------------------------------- > read pv->cpustate > (it is PV_CPU_ACTIVE) >...

...QSPINLOCK_LOCKED_SLOWPATH); > if (lockval == 0) { > /* > * Can exit now as the lock is free > */ > ACCESS_ONCE(pv->cpustate) = PV_CPU_ACTIVE; > *count = 0; > return; > } > __queue_hibernate(); > > Nothing protects from writing qlock->lock before pv->cpustate is read, > leading to this: > > Lock holder Waiter > --------------------------------------------------------------- > read pv->cpustate > (it is PV_CPU_ACTIVE) >...

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