Re: [PATCH 1/2 v5 typo updated] tracing/uprobes: Supportftrace_event_file base multibuffer
From: Oleg Nesterov
Date: Thu Jul 04 2013 - 14:02:00 EST
On 07/04, zhangwei(Jovi) wrote:
>
>
On 2013年7月4日 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.
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>> (Perhaps this will be fix in future, kprobe dont't have this
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>> limitation now)
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>
>
> So why does this limitation exist? Didn't we support this kind of thing
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> 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
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is associated with trace_uprobe tightly at present, so we cannot assign
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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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