linux-kernel - [RFC v1 0/2] RCU dyntick nesting counter cleanups

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Date:   Mon, 26 Aug 2019 21:33:52 -0400
From:   "Joel Fernandes (Google)" <joel@...lfernandes.org>
To:     linux-kernel@...r.kernel.org
Cc:     "Joel Fernandes (Google)" <joel@...lfernandes.org>,
        Frederic Weisbecker <fweisbec@...il.com>,
        Jonathan Corbet <corbet@....net>,
        Josh Triplett <josh@...htriplett.org>, kernel-team@...roid.com,
        Lai Jiangshan <jiangshanlai@...il.com>,
        linux-doc@...r.kernel.org,
        Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
        Mauro Carvalho Chehab <mchehab+samsung@...nel.org>,
        "Paul E. McKenney" <paulmck@...nel.org>, rcu@...r.kernel.org,
        Steven Rostedt <rostedt@...dmis.org>
Subject: [RFC v1 0/2] RCU dyntick nesting counter cleanups

These patches clean up the usage of dynticks nesting counters simplifying the
code, while preserving the usecases.

It is a much needed simplification, makes the code less confusing, and prevents
future bugs such as those that arise from forgetting that the
dynticks_nmi_nesting counter is not a simple counter and can be "crowbarred" in
common situations.

Several nights of rcutorture testing with CONFIG_RCU_EQS_DEBUG on all RCU
kernel configurations have survived without any splats.

Further testing is in progress, hence marked as RFC!

thanks,

 - Joel

Joel Fernandes (Google) (2):
rcu/tree: Clean up dynticks counter usage
rcu/tree: Remove dynticks_nmi_nesting counter

.../Data-Structures/Data-Structures.rst       | 31 ++----
Documentation/RCU/stallwarn.txt               |  6 +-
kernel/rcu/rcu.h                              |  4 -
kernel/rcu/tree.c                             | 98 +++++++++----------
kernel/rcu/tree.h                             |  4 +-
kernel/rcu/tree_stall.h                       |  4 +-
6 files changed, 64 insertions(+), 83 deletions(-)

--
2.23.0.187.g17f5b7556c-goog