lkml.org 
[lkml]   [2011]   [Apr]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [RFC][PATCH 5/9] perf: Simplify and fix __perf_install_in_context
From
Date
On Sat, 2011-04-09 at 21:17 +0200, Peter Zijlstra wrote:
> plain text document attachment (perf_install_in_context.patch)
> Currently __perf_install_in_context() will try and schedule in the
> event irrespective of our event scheduling rules, that is, we try to
> schedule CPU-pinned, TASK-pinned, CPU-flexible, TASK-flexible, but
> when creating a new event we simply try and schedule it on top of
> whatever is already on the PMU, this can lead to errors for pinned
> events.
>
> Therefore, simplify things and simply schedule everything out, add the
> event to the corresponding context and schedule everything back in.
>
> This also nicely handles the case where with
> __ARCH_WANT_INTERRUPTS_ON_CTXSW the IPI can come right in the middle
> of schedule, before we managed to call perf_event_task_sched_in().
>
> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
> ---
> kernel/perf_event.c | 80 ++++++++++++++++++++++------------------------------
> 1 file changed, 35 insertions(+), 45 deletions(-)
>
> Index: linux-2.6/kernel/perf_event.c
> ===================================================================
> --- linux-2.6.orig/kernel/perf_event.c
> +++ linux-2.6/kernel/perf_event.c
> @@ -1476,8 +1476,12 @@ static void add_event_to_ctx(struct perf
> event->tstamp_stopped = tstamp;
> }
>
> -static void perf_event_context_sched_in(struct perf_event_context *ctx,
> - struct task_struct *tsk);
> +static void task_ctx_sched_out(struct perf_event_context *ctx);
> +static void
> +ctx_sched_in(struct perf_event_context *ctx,
> + struct perf_cpu_context *cpuctx,
> + enum event_type_t event_type,
> + struct task_struct *task);
>
> /*
> * Cross CPU call to install and enable a performance event
> @@ -1488,20 +1492,31 @@ static int __perf_install_in_context(vo
> {
> struct perf_event *event = info;
> struct perf_event_context *ctx = event->ctx;
> - struct perf_event *leader = event->group_leader;
> struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
> - int err;
> + struct perf_event_context *task_ctx = cpuctx->task_ctx;
> + struct task_struct *task = current;
> +
> + perf_ctx_lock(cpuctx, cpuctx->task_ctx);

perf_ctx_lock(cpuctx, task_ctx)

since task_ctx is assigned with cpuctx->task_ctx.

Lin Ming



\
 
 \ /
  Last update: 2011-04-11 10:15    [from the cache]
©2003-2011 Jasper Spaans