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From: Bernhard Walle <bwalle@suse.de>
To: Jay Lan <jlan@sgi.com>
Cc: vgoyal@in.ibm.com, Takenori Nagano <t-nagano@ah.jp.nec.com>,
	k-miyoshi@cb.jp.nec.com, kexec@lists.infradead.org,
	linux-kernel@vger.kernel.org,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	Keith Owens <kaos@ocs.com.au>,
	Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [patch] add kdump_after_notifier
Date: Tue, 21 Aug 2007 15:21:19 +0200	[thread overview]
Message-ID: <20070821132119.GC4244@suse.de> (raw)
In-Reply-To: <46CAE627.7070908@sgi.com>

* Jay Lan <jlan@sgi.com> [2007-08-21 15:18]:
> Vivek Goyal wrote:
> > On Thu, Aug 16, 2007 at 06:26:35PM +0900, Takenori Nagano wrote:
> >> Vivek Goyal wrote:
> >>  > So for the time being I think we can put RAS tools on die notifier list
> >>> and if it runs into issues we can always think of creating a separate list.
> >>>
> >>> Few things come to mind.
> >>>
> >>> - Why there is a separate panic_notifier_list? Can't it be merged with
> >>>   die_chain? die_val already got one of the event type as PANIC. If there
> >>>   are no specific reasons then we should merge the two lists. Registering
> >>>   RAS tools on a single list is easier.
> >> I think it is difficult, because die_chain is defined by each architecture.
> >>
> > 
> > I think die_chain is arch independent definition (kernel/die_notifier.c)? 
> > But anyway, to begin with it can be done only for panic_notifier.
> > 
> >>> - Modify Kdump to register on die_chain list. 
> >>> - Modify Kdb to register on die_chain list.
> >>> - Export all the registered members of die_chain through sysfs along with
> >>>   their priorities. Priorities should be modifiable. Most likely one 
> >>>   shall have to introduce additional field in struct notifier_block. This
> >>>   field will be a string as an identifier of the user registerd. e.g
> >>>   "Kdump", "Kdb" etc.
> >>>
> >>> Now user will be able to view all the die_chain users through sysfs and
> >>> be able to modify the order in which these should run by modifying their
> >>> priority. Hence all the RAS tools can co-exist.
> >> This is my image of your proposal.
> >>
> >> - Print current order
> >>
> >> # cat /sys/class/misc/debug/panic_notifier_list
> >> priority   name
> >> 1          IPMI
> >> 2          watchdog
> >> 3          Kdb
> >> 4          Kdump
> >>
> > 
> > I think Bernhard's suggestion looks better here. I noticed that 
> > /sys/kernel/debug is already present. So how about following.
> > 
> > /sys/kernel/debug/kdump/priority
> > /sys/kernel/debug/kdb/priority
> > /sys/kernel/debug/IPMI/priority
> 
> Why separate priority files is better than a central file?
> At least i think you get a grand picture of priority being
> defined for all parties with a central file?

Well, it's more intuitive to set the priority in that case. You don't
have to know a special syntax. However, it may be a good idea to
implement a second read-only file that lists the sorted priorities in
that order the kernel executues the handlers the handlers.

> What do we decide priority if more than one component has
> the same priority value?

You can check this and return EINVAL in that case.


Thanks,
   Bernhard

  reply	other threads:[~2007-08-21 13:21 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-07-19 12:15 Takenori Nagano
2007-07-26 14:07 ` Bernhard Walle
2007-07-26 15:32   ` Vivek Goyal
2007-07-26 15:34     ` Bernhard Walle
2007-07-26 15:44       ` Vivek Goyal
2007-07-26 15:47         ` Bernhard Walle
2007-07-26 15:54           ` Vivek Goyal
2007-07-26 16:14             ` Bernhard Walle
2007-07-26 16:21               ` Bernhard Walle
2007-07-26 23:28             ` Takenori Nagano
2007-07-30  9:16               ` Vivek Goyal
2007-07-30 13:42                 ` Eric W. Biederman
2007-07-31  5:55                   ` Takenori Nagano
2007-07-31  6:53                     ` Eric W. Biederman
2007-08-01  9:26                       ` Takenori Nagano
2007-08-01 10:00                         ` Eric W. Biederman
2007-08-02  8:11                           ` Takenori Nagano
2007-08-02 11:28                           ` Vivek Goyal
2007-08-03  4:05                             ` Keith Owens
2007-08-03  6:25                               ` Andrew Morton
2007-08-03  6:34                                 ` Keith Owens
2007-08-03  7:37                                   ` Andrew Morton
2007-08-03  7:10                                 ` Eric W. Biederman
2007-08-05 11:07                               ` Vivek Goyal
2007-08-14  8:34                                 ` Takenori Nagano
2007-08-14  8:37                                   ` Bernhard Walle
2007-08-14  8:48                                     ` Takenori Nagano
2007-08-14  8:53                                       ` Bernhard Walle
2007-08-14 13:24                                     ` Vivek Goyal
2007-08-16  9:26                                       ` Takenori Nagano
2007-08-16  9:45                                         ` Bernhard Walle
2007-08-17 10:56                                         ` Vivek Goyal
2007-08-21  7:45                                           ` Takenori Nagano
2007-08-23  3:52                                             ` Vivek Goyal
2007-08-21 13:18                                           ` Jay Lan
2007-08-21 13:21                                             ` Bernhard Walle [this message]
2007-08-23  3:56                                             ` Vivek Goyal
2007-08-23 17:34                                               ` Jay Lan

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