linux-kernel - [PATCH 0/2] timer: Fix missing dynticks kick

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Message-Id: <1402601641-28462-1-git-send-email-fweisbec@gmail.com>
Date:	Thu, 12 Jun 2014 21:33:59 +0200
From:	Frederic Weisbecker <fweisbec@...il.com>
To:	Thomas Gleixner <tglx@...utronix.de>
Cc:	LKML <linux-kernel@...r.kernel.org>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Viresh Kumar <viresh.kumar@...aro.org>
Subject: [PATCH 0/2] timer: Fix missing dynticks kick

Thomas,

Viresh has spotted and fixed an interesting issue. When a timer list
is enqueued or updated on a (idle or full) dynticks target, we kick it
with an IPI.

At least that's what we do on add_timer_on() but the mod_timer*() family
doesn't handle that. I think that's because we had assumptions that
mod_timer() never enqueues to remote idle targets. But that's subject
to subtle races where a CPU can become dynticks-idle between a call to
get_nohz_timer_target() and the time we actually lock the new target.

Moreover we forgot to handle full dynticks targets selected by __mod_timer().

That patchset should fixes all those issues.

git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks.git
	timers/missing-kick

Thanks,
	Frederic
---

Viresh Kumar (2):
      timer: Store cpu-number in 'struct tvec_base'
      timer: Kick dynticks targets on mod_timer*() calls

 kernel/timer.c | 34 ++++++++++++++++++----------------
 1 file changed, 18 insertions(+), 16 deletions(-)
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