linux-kernel - Re: [RFC PATCH 08/17] perf: Allow inheritance for detached events

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Date:   Fri, 06 Oct 2017 14:40:55 +0300
From:   Alexander Shishkin <alexander.shishkin@...ux.intel.com>
To:     Peter Zijlstra <peterz@...radead.org>
Cc:     Ingo Molnar <mingo@...hat.com>, linux-kernel@...r.kernel.org,
        acme@...hat.com, kirill.shutemov@...ux.intel.com,
        Borislav Petkov <bp@...en8.de>, rric@...nel.org
Subject: Re: [RFC PATCH 08/17] perf: Allow inheritance for detached events

Peter Zijlstra <peterz@...radead.org> writes:

> On Tue, Sep 05, 2017 at 04:30:17PM +0300, Alexander Shishkin wrote:
>> This enables inheritance for detached events. Unlike traditional events,
>> these do not have parents: inheritance produces a new independent event
>> with the same attribute. If the 'parent' event has a ring buffer, so will
>> the new event. Considering the mlock accounting, this buffer allocation
>> may fail, which in turn will fail the parent's fork, something to be
>> aware of.
>> 
>> This also effectively disables context cloning, because unlike the
>> traditional events, these will each have its own ring buffer and
>> context switch optimization can't work.
>
> Right, so this thing is icky... as you know. More naming issues though,
> what will you go and call those files.

Yes. The failing-the-fork ickiness is dealt with later on in 11/17.
But true about the naming.

Regards,
--
Alex