watchdog/core: Get rid of the thread teardown/setup dance
authorThomas Gleixner <tglx@linutronix.de>
Tue, 12 Sep 2017 19:37:11 +0000 (21:37 +0200)
committerIngo Molnar <mingo@kernel.org>
Thu, 14 Sep 2017 09:41:06 +0000 (11:41 +0200)
commitd57108d4f6791291e89d980e7f7a3566c32ab188
treeb51bf3c0fb0b6f283a3f72eb16b56825365fab6d
parent2eb2527f847d1bd8d8fb9db1e8139db5d6eddb36
watchdog/core: Get rid of the thread teardown/setup dance

The lockup detector reconfiguration tears down all watchdog threads when
the watchdog is disabled and sets them up again when its enabled.

That's a pointless exercise. The watchdog threads are not consuming an
insane amount of resources, so it's enough to set them up at init time and
keep them in parked position when the watchdog is disabled and unpark them
when it is reenabled. The smpboot thread infrastructure takes care of
keeping the force parked threads in place even across cpu hotplug.

Aside of that the code implements the park/unpark facility of smp hotplug
threads on its own, which is even more pointless. We have functionality in
the smpboot thread code to do so.

Use the new thread management functions and get rid of the unholy mess.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Don Zickus <dzickus@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Ulrich Obergfell <uobergfe@redhat.com>
Link: http://lkml.kernel.org/r/20170912194147.470370113@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
kernel/watchdog.c