Re: [PATCH 1/3] perf: add context field to perf_event

Avi Kivity
2011-07-12T09:17:02Z

On 07/12/2011 12:14 PM, Peter Zijlstra wrote:
> On Tue, 2011-07-12 at 12:08 +0300, Avi Kivity wrote:
> > Similar, but with stronger guarantees: when the function is called,
> > current == p, and the task was either sleeping or in userspace.
>
> If the task is sleeping, current can never be p.

The guarantee is that the task was sleeping just before the function is
called. Of course it's woken up to run the function.

The idea is that you run the function in a known safe point to avoid
extra synchronization.

--
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.