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

From: Avi Kivity
Date: Tue Jul 12 2011 - 05:17:07 EST


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.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/