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From: Peter Zijlstra <peterz@infradead.org>
To: Borislav Petkov <bp@amd64.org>
Cc: Ingo Molnar <mingo@kernel.org>,
	Frederic Weisbecker <fweisbec@gmail.com>,
	Ingo Molnar <mingo@elte.hu>, Steven Rostedt <rostedt@goodmis.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Borislav Petkov <borislav.petkov@amd.com>
Subject: Re: [PATCH 1/2] perf: Add persistent event facilities
Date: Fri, 18 May 2012 15:37:47 +0200	[thread overview]
Message-ID: <1337348267.573.37.camel@twins> (raw)
In-Reply-To: <20120518125505.GK20215@aftab.osrc.amd.com>

On Fri, 2012-05-18 at 14:55 +0200, Borislav Petkov wrote:
> It is an interesting question how we handle that RO/RW thing?

RO buffers overwrite, RW buffers loose events.

We could allow both for persistent under the constraints:

 VM_SHARED - must imply !VM_WRITE since multiple people writing to the
             control page will get 'interesting' very fast.

 !VM_SHARED - must fail mmap() of the debugfs file if there's already
              an existing user.

Note that even RW buffers only allows writes to the control page, a
write to the actual data itself will generate a fault.

  reply	other threads:[~2012-05-18 13:38 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-03-21 14:34 [RFC PATCH 0/2] perf: Add persistent event facilities Borislav Petkov
2012-03-21 14:34 ` [PATCH 1/2] " Borislav Petkov
2012-05-18  9:58   ` Peter Zijlstra
2012-05-18 10:01     ` Borislav Petkov
2012-05-18 10:00   ` Peter Zijlstra
2012-05-18 10:02   ` Peter Zijlstra
2012-05-18 10:09   ` Peter Zijlstra
2012-05-18 10:49     ` Borislav Petkov
2012-05-18 10:14   ` Peter Zijlstra
2012-05-18 11:03     ` Borislav Petkov
2012-05-18 11:24       ` Peter Zijlstra
2012-05-18 11:59         ` Ingo Molnar
2012-05-18 12:55           ` Borislav Petkov
2012-05-18 13:37             ` Peter Zijlstra [this message]
2012-05-18 14:09               ` Borislav Petkov
2012-05-18 14:14                 ` Peter Zijlstra
2012-05-18 14:21                   ` Borislav Petkov
2012-05-18 14:37                     ` Peter Zijlstra
2012-05-18 15:24                       ` Borislav Petkov
2012-05-31 17:33     ` Borislav Petkov
2012-03-21 14:34 ` [PATCH 2/2] x86, mce: Add persistent MCE event Borislav Petkov
2012-03-22  8:36   ` Srivatsa S. Bhat
2012-03-22 11:40     ` Borislav Petkov
2012-03-22 11:57       ` Srivatsa S. Bhat
2012-03-23 12:31   ` Ingo Molnar
2012-03-23 13:30     ` Borislav Petkov
2012-03-24  7:37       ` Ingo Molnar
2012-03-24  9:00         ` Borislav Petkov
2012-03-24  9:15           ` Ingo Molnar
2012-05-15 15:32             ` Borislav Petkov
2012-05-18  8:18               ` Ingo Molnar
2012-05-18 10:03                 ` Borislav Petkov

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