linux-kernel - [PATCH 0/3] add new notifier function ,take4

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Date:	Wed, 23 Apr 2008 20:11:19 +0900
From:	Takenori Nagano <t-nagano@...jp.nec.com>
To:	linux-kernel@...r.kernel.org,
	Andrew Morton <akpm@...ux-foundation.org>
CC:	kdb@....sgi.com, vgoyal@...hat.com,
	"Eric W. Biederman" <ebiederm@...ssion.com>,
	kexec@...ts.infradead.org, Keith Owens <kaos@....com.au>,
	Nick Piggin <nickpiggin@...oo.com.au>,
	Randy Dunlap <rdunlap@...otime.net>, greg@...ah.com,
	bwalle@...e.de, k-miyoshi@...jp.nec.com
Subject: [PATCH 0/3] add new notifier function ,take4

Hi,

changelog take3 -> take4

- Rebased 2.6.25-mm1
- Add a document
- Add kdump on panic_notifier

These patches add new notifier function and implement it to panic_notifier_list.
We used the hardcoded notifier chain so far, but it was not flexible. New
notifier is very flexible, because user can change a list of order by control files.

And, third patch moves crash_kexec() to panic_notifier. It helps us to do
something before taking a crash dump. It's useful for some RAS tools developer.
If you want to use it, you have to set config option DUMP_ON_PANIC_NOTIFIER to
Y. Default value of DUMP_ON_PANIC_NOTIFIER is N.
If you set DUMP_ON_PANIC_NOTIFIER to N, kdump has no difference before.

------
Example)

# cd /sys/kernel/notifiers/
# ls
panic_notifier_list
# cd panic_notifier_list/
# ls
ipmi_msghandler  ipmi_wdog
# insmod notifier_test.ko
# ls
ipmi_msghandler  ipmi_wdog  notifier_test1  notifier_test2
# cat */priority
200
150
500
1000
Kernel panic - not syncing: Panic by panic_module.
__tunable_atomic_notifier_call_chain enter
notifier_test: notifier_test_panic2() is called.
notifier_test: notifier_test_panic() is called.
msg_handler:panic_event was called.
ipmi_wdog:wdog_panic_handler was called.

.....(reboot)

# cd /sys/kernel/notifiers/panic_notifier_list/
# ls
ipmi_msghandler  ipmi_wdog  notifier_test1  notifier_test2
# cat */priority
200
150
500
1000
# echo 10000 > ipmi_msghandler/priority
# echo 5000 > ipmi_wdog/priority
# echo 3000 > notifier_test1/priority
# echo 1500 > notifier_test2/priority
# cat */priority
10000
5000
3000
1500
Kernel panic - not syncing: Panic by panic_module.
__tunable_atomic_notifier_call_chain enter
msg_handler:panic_event was called.
ipmi_wdog:wdog_panic_handler was called.
notifier_test: notifier_test_panic() is called.
notifier_test: notifier_test_panic2() is called.

--
Takenori Nagano <t-nagano@...jp.nec.com>

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