Re: [PATCH 1/2 v5 typo updated] tracing/uprobes: Supportftrace_event_file base multibuffer

[Oleg Nesterov]

On 07/04, zhangwei(Jovi) wrote:
>
> On 2013/7/4 15:41, Namhyung Kim wrote:
> >>
> >> Even though we allow multi-uprobes instances now,
> >> but TP_FLAG_PROFILE/TP_FLAG_TRACE are still mutually exclusive
> >> in probe_event_enable currently, this means we cannot allow
> >> one user is using uprobe-tracer, and another user is using
> >> perf-probe on same uprobe concurrently.
> >> (Perhaps this will be fix in future, kprobe dont't have this
> >> limitation now)
> >
> > So why does this limitation exist?  Didn't we support this kind of thing
> > in the original code?

For no reason.

> Yes, it existed(maybe not exist before uprobe pre-filter work),

No, it was always here and I never understood it.

> because uprobe filter
> is associated with trace_uprobe tightly at present, so we cannot assign
> TP_FLAG_PROFILE/TP_FLAG_TRACE for same trace_uprobe with different filter.

More precisely, TRACE_REG_REGISTER should participate (inc/dec nr_systemwide)
if CONFIG_PERF_EVENTS.

> Perhaps we need to remove the limitation in future.

Yes, I'll remove it.

Oleg.

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