search for: pv_qspinlock_en

...shold only if PV qspinlock is enabled */ #define PSPIN_THRESHOLD (1 << 10) -#define MAX_NODES 4 +/* + * We need to double the number of per-cpu mcs_spinlock structures to hold + * additional fields specific to para-virtualization support. + */ #ifdef CONFIG_PARAVIRT_SPINLOCKS -#define pv_qspinlock_enabled() static_key_false(&paravirt_spinlocks_enabled) +# define MAX_NODES 8 +# define pv_qspinlock_enabled() static_key_false(&paravirt_spinlocks_enabled) #else -#define pv_qspinlock_enabled() false +# define MAX_NODES 4 +# define pv_qspinlock_enabled() false #endif /* @@ -243,6 +248,...

...irst in line, but when it decides to queue, it must go to the tail. 4: The idea is to prevent unfairness by queueing after a while of useless looping. Magic value should be set a bit above the time it takes an active pending bit holder to go through the loop. 4 looks enough. We can use either pv_qspinlock_enabled() or cpu_has_hypervisor. I presume that we never want this to happen in a VM and that we won't have pv_qspinlock_enabled() without cpu_has_hypervisor. diff --git a/kernel/locking/qspinlock.c b/kernel/locking/qspinlock.c index 37b5c7f..cd45c27 100644 --- a/kernel/locking/qspinlock.c +++ b/...

...irst in line, but when it decides to queue, it must go to the tail. 4: The idea is to prevent unfairness by queueing after a while of useless looping. Magic value should be set a bit above the time it takes an active pending bit holder to go through the loop. 4 looks enough. We can use either pv_qspinlock_enabled() or cpu_has_hypervisor. I presume that we never want this to happen in a VM and that we won't have pv_qspinlock_enabled() without cpu_has_hypervisor. diff --git a/kernel/locking/qspinlock.c b/kernel/locking/qspinlock.c index 37b5c7f..cd45c27 100644 --- a/kernel/locking/qspinlock.c +++ b/...

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

v9->v10: - Make some minor changes to qspinlock.c to accommodate review feedback. - Change author to PeterZ for 2 of the patches. - Include Raghavendra KT's test results in patch 18. 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

v9->v10: - Make some minor changes to qspinlock.c to accommodate review feedback. - Change author to PeterZ for 2 of the patches. - Include Raghavendra KT's test results in patch 18. 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

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

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