* Huang Ying <ying.huang@xxxxxxxxx> wrote: > Hi, Thomas, > > On Tue, 2010-10-26 at 12:53 +0800, Thomas Gleixner wrote: > > B1;2401;0cLen, > > > > On Mon, 25 Oct 2010, Len Brown wrote: > > > > > > NAKed-by: Ingo Molnar <mingo@xxxxxxx> > > > > > > Everybody knows that Linux has a lot to learn about RAS. > > > > > > I think to catch up, we need to play to Linux's strengths > > > of continuous improvement. If we halt patches in this area > > > then we could wait forever for the "perfect design". > > > > it's not about perfect design. It's about creating new user space > > ABIs. The patches introduce another error reporting user space ABI > > with an ad hoc "fits the needs" design. > > > > This is my major point of objection. > > > > I agree that Linux needs improvement on the RAS side, but does this > > lack of features justify a new user space ABI which is totally > > disconnected to existing RAS facilities ? > > > > No, it does not. It's not our problem that Intel wasted time on > > creating another character device driver to report errors to user > > space. The time spent to do so would have been sufficient to do a > > proper integration into the existing infrastructure. > > > > I would not care at all if these patches would just introduce some > > weird in kernel interfaces as we can clean that up at will. But > > introducing a new user space ABI is setting the disconnect of RAS > > related facilities into stone. > > > > From Kconfig: > > > > EDAC is designed to report errors in the core system. > > These are low-level errors that are reported in the CPU or > > supporting chipset or other subsystems: > > memory errors, cache errors, PCI errors, thermal throttling, etc.. > > If unsure, select 'Y'. > > > > So please explain why your error reporting is so different from the > > above that it justifies a separate facility. And you better come up > > with a real good explanation other than we looked at EDAC and it did > > not fit our needs. > > As far as I know, EDAC guys plan to use some other "perfect interface" in the > future. So I think the current state is really waiting for the "perfect design". Not sure what you mean by this, but Boris has posted links to his latest patch-set in this thread, see: http://kerneltrap.org/mailarchive/linux-kernel/2010/8/6/4603847 The Git coordinates are: git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace.git, branch tip/perf/parse-events The 'persistent events' facility he has prototyped there appears to be a good potential match for the ERST store. It would be very useful to have another feature there: to mark persistent events as 'dump into syslog on bootup', so that for example the contents of the ERST log could be dumped right on bootup. [but ERST would not be the only persistent event that could be marked like that.] Note that we dont need/want other ABI accesses to the ERST log (i.e. we dont want /dev/erst-dbg), because we want the benefits of the generalization: tooling (RAS and other tooling) should learn how to deal with persistent events - not learn how to deal with ERST logs ... or with warm bootup RAM-embedded logs ... or to deal with kcrash embedded kernel logs ... etc. There are many obvious advantages from implementing it like that: there's no need to special-code ERST to printk or ERST to whatever other facility cross links - it would be part of a generic/uniform event logging facility to begin with. ERST would only implement its own, narrow, hardware-specific event accessor methods - nothing else. Basically a small 'event driver'. This would be the most optimal, smallest, easiest to maintain approach - with no facility duplication and no fragmentation. It's certainly more work as well _for the first such example_ - but from that point on any new hardware facility can be added with ease, and those too will fit into existing tooling in a very natural way. So please help out with the persistent events work. If you need any pointers we'd be glad to help. Thanks, Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
