Date: Sun, 1 Nov 2009 21:38:39 -0800
From: Arjan van de Ven <arjan@infradead.org>
To: Paul Mackerras <paulus@samba.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>, Ingo Molnar <mingo@elte.hu>,
       LKML <linux-kernel@vger.kernel.org>,
       Arjan van de Ven <arjan@linux.intel.com>,
       "K.Prasad" <prasad@linux.vnet.ibm.com>,
       Alan Stern <stern@rowland.harvard.edu>,
       Arnaldo Carvalho de Melo <acme@redhat.com>,
       Steven Rostedt <rostedt@goodmis.org>,
       Jan Kiszka <jan.kiszka@siemens.com>, Jiri Slaby <jirislaby@gmail.com>,
       Li Zefan <lizf@cn.fujitsu.com>, Avi Kivity <avi@redhat.com>,
       Mike Galbraith <efault@gmx.de>, Masami Hiramatsu <mhiramat@redhat.com>,
       Paul Mundt <lethal@linux-sh.org>, Jan Kiszka <jan.kiszka@web.de>
Subject: Re: [PATCH 1/6] perf/core: Provide a kernel-internal interface to
 get to performance counters
Message-ID: <20091101213839.28b4054a@infradead.org>
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	<1257109753-6464-2-git-send-email-fweisbec@gmail.com>
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On Mon, 2 Nov 2009 14:46:55 +1100
Paul Mackerras <paulus@samba.org> wrote:

> Frederic Weisbecker writes:
> 
> >  /*
> > + * perf_event_create_kernel_counter
> > + * MUST be called from a kernel thread.
> 
> Why?  The reason for this requirement isn't obvious to me.  It would
> be good to have the reason documented in the comment for the sake of
> people modifying the code in future.

because if you call it from another context it will attach to that
context... and go away when that context goes away...


-- 
Arjan van de Ven 	Intel Open Source Technology Centre
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