Messages in this thread | | | Date | Thu, 11 Nov 2010 07:17:25 +0100 | From | Borislav Petkov <> | Subject | Re: [PATCH 03/20] x86, mce: Add persistent MCE event |
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On Wed, Nov 10, 2010 at 05:21:57PM -0500, Ingo Molnar wrote: > > * Ben Gamari <bgamari@gmail.com> wrote: > > > On Thu, 4 Nov 2010 16:36:39 +0100, Borislav Petkov <bp@amd64.org> wrote: > > > From: Borislav Petkov <borislav.petkov@amd.com> > > > > > > Add the necessary glue to enable the mce_record tracepoint on boot > > > turning it into a persistent event. This exports the MCE buffer > > > read-only to a userspace daemon which will hook into it through debugfs > > > when booting is finished. > > > > While MCE technically is a diagnostics service, do we want to start adding > > dependencies on debugfs in long-running, common-place daemons? I was under the > > impression we were to avoid using debugfs for anything other than values for > > one-off debugging. > > See this current discussion thread on lkml: > > [RFC][PATCH] perf: sysfs type id > > Events are being added to sysfs as we want to avoid the debugfs dependency.
Yep, event enumeration will land in /sysfs eventually but in this case debugfs is used to export the buffers with the events recorded so far to the daemon which mmaps them. And I remember also being mentioned that debugfs will thus be always compiled in because of that.
In any case, we need some kind of a facility with which to export those buffers for userspace to mmap. sysfs is clearly not that and debugfs is what we currently use. I'm open for better suggestions though.
Thanks.
-- Regards/Gruss, Boris.
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