Re: [PATCH 1/4] powerpc/pseries: Fix hcall tracing recursion in pv queued spinlocks

2021-05-02 Thread Michael Ellerman
Nicholas Piggin writes: > Excerpts from Naveen N. Rao's message of April 27, 2021 11:43 pm: >> Nicholas Piggin wrote: >>> The paravit queued spinlock slow path adds itself to the queue then >>> calls pv_wait to wait for the lock to become free. This is implemented >>> by calling H_CONFER to donate

Re: [PATCH 1/4] powerpc/pseries: Fix hcall tracing recursion in pv queued spinlocks

2021-04-30 Thread Nicholas Piggin
Excerpts from Naveen N. Rao's message of April 27, 2021 11:43 pm: > Nicholas Piggin wrote: >> The paravit queued spinlock slow path adds itself to the queue then >> calls pv_wait to wait for the lock to become free. This is implemented >> by calling H_CONFER to donate cycles. >> >> When hcall trac

Re: [PATCH 1/4] powerpc/pseries: Fix hcall tracing recursion in pv queued spinlocks

2021-04-27 Thread Naveen N. Rao
Nicholas Piggin wrote: The paravit queued spinlock slow path adds itself to the queue then calls pv_wait to wait for the lock to become free. This is implemented by calling H_CONFER to donate cycles. When hcall tracing is enabled, this H_CONFER call can lead to a spin lock being taken in the tra

[PATCH 1/4] powerpc/pseries: Fix hcall tracing recursion in pv queued spinlocks

2021-04-22 Thread Nicholas Piggin
The paravit queued spinlock slow path adds itself to the queue then calls pv_wait to wait for the lock to become free. This is implemented by calling H_CONFER to donate cycles. When hcall tracing is enabled, this H_CONFER call can lead to a spin lock being taken in the tracing code, which will res