Re: [RFC PATCH 2/2] perf: Filter events based on perf-namespace

From	Aravinda Prasad <aravinda@linux.vnet.ibm.com>
Newsgroups	linux.kernel
Subject	Re: [RFC PATCH 2/2] perf: Filter events based on perf-namespace
Date	2016-07-12 18:30 +0200
Message-ID	<rU8Jk-7nR-5@gated-at.bofh.it> (permalink)
References	(2 earlier) <rOH73-2eF-9@gated-at.bofh.it> <rU2aS-2Zl-31@gated-at.bofh.it> <rU4mm-4l8-21@gated-at.bofh.it> <rU5iq-4W1-21@gated-at.bofh.it> <rU5BM-5k0-43@gated-at.bofh.it>
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On Tuesday 12 July 2016 06:34 PM, Peter Zijlstra wrote:
> On Tue, Jul 12, 2016 at 03:41:42PM +0300, Nikolay Borisov wrote:
> 
>> Namespaces and cgroups are completely orthogonal to one another. 
> 
> Then how do you specify what your new 'root' is? Surely you must first
> create a cgroup and then confine yourself to that?

No need to create cgroup and confine processes to that cgroup. The below
check during event filtering will take care:

+	if (cpuctx->perf_ns != event->perf_ns)
+		return false;

event->perf_ns is set during perf_event_alloc():

+	if (current->nsproxy->perf_ns != &init_perf_ns) {
+		/*
+		 * If we are called from our own perf namespace, set
+		 * event->perf_ns
+		 */
+		event->perf_ns = current->nsproxy->perf_ns;
+		[...]
+	}

> 
>> Also in the v1 of cgroups it's possible to have a process member of
>> more than 1 cgroup.
> 
> Yeah, so? We only care about the perf controller obviously.
> 

-- 
Regards,
Aravinda

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Re: [RFC PATCH 2/2] perf: Filter events based on perf-namespace Aravinda Prasad <aravinda@linux.vnet.ibm.com> - 2016-07-12 11:30 +0200
  Re: [RFC PATCH 2/2] perf: Filter events based on perf-namespace Peter Zijlstra <peterz@infradead.org> - 2016-07-12 13:50 +0200
    Re: [RFC PATCH 2/2] perf: Filter events based on perf-namespace Nikolay Borisov <kernel@kyup.com> - 2016-07-12 14:50 +0200
      Re: [RFC PATCH 2/2] perf: Filter events based on perf-namespace Peter Zijlstra <peterz@infradead.org> - 2016-07-12 15:10 +0200
        Re: [RFC PATCH 2/2] perf: Filter events based on perf-namespace ebiederm@xmission.com (Eric W. Biederman) - 2016-07-12 16:10 +0200
          Re: [RFC PATCH 2/2] perf: Filter events based on perf-namespace Peter Zijlstra <peterz@infradead.org> - 2016-07-12 16:30 +0200
            Re: [RFC PATCH 2/2] perf: Filter events based on perf-namespace Aravinda Prasad <aravinda@linux.vnet.ibm.com> - 2016-07-12 18:10 +0200
        Re: [RFC PATCH 2/2] perf: Filter events based on perf-namespace Aravinda Prasad <aravinda@linux.vnet.ibm.com> - 2016-07-12 18:30 +0200

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