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From: Peter Zijlstra <peterz@infradead.org>
To: Boqun Feng <boqun.feng@gmail.com>
Cc: linux-kernel@vger.kernel.org, Ingo Molnar <mingo@kernel.org>,
	"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
	Josh Triplett <josh@joshtriplett.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
	Lai Jiangshan <jiangshanlai@gmail.com>,
	sasha.levin@oracle.com
Subject: Re: [RFC v2 0/6] Track RCU dereferences in RCU read-side critical sections
Date: Thu, 25 Feb 2016 15:32:43 +0100	[thread overview]
Message-ID: <20160225143243.GP6357@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <1455602265-16490-1-git-send-email-boqun.feng@gmail.com>

On Tue, Feb 16, 2016 at 01:57:39PM +0800, Boqun Feng wrote:
> As a characteristic of RCU, read-side critical sections have a very
> loose connection with rcu_dereference()s, which is you can only be sure
> about an rcu_dereference() might be called in some read-side critical
> section, but if code gets complex, you may not be sure which read-side
> critical section exactly, this might be also an problem for some other
> locking mechanisms, that is the critical sections protecting data and
> the data accesses protected are not clearly correlated.
> 
> In this series, we are introducing LOCKED_ACCESS framework and based on
> which, we implement the RCU_LOCKED_ACCESS functionality to give us a
> clear hint: which rcu_dereference() happens in which RCU read-side
> critical section. 
> 
> After this series applied, and if CONFIG_RCU_LOCKED_ACCESS=y, the proc
> file /proc/locked_access/rcu will show all relationships collected so
> far for rcu_read_lock() and their friends and rcu_dereference*().
> 

But why !? What does this bring us, why do I want to even look at these
patches?

  parent reply	other threads:[~2016-02-25 14:32 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-02-16  5:57 [RFC v2 0/6] Track RCU dereferences in RCU read-side critical sections Boqun Feng
2016-02-16  5:57 ` [RFC v2 1/6] lockdep: Add helper functions of irq_context Boqun Feng
2016-02-17  0:17   ` Paul E. McKenney
2016-04-23 12:53   ` [tip:locking/urgent] locking/lockdep: Fix ->irq_context calculation tip-bot for Boqun Feng
2016-02-16  5:57 ` [RFC v2 2/6] lockdep: LOCKED_ACCESS: Introduce locked access class and acqchain Boqun Feng
2016-02-16  5:57 ` [RFC v2 3/6] lockdep: LOCKED_ACCESS: Maintain the keys of acqchains Boqun Feng
2016-02-16  5:57 ` [RFC v2 4/6] lockdep: LOCKED_ACCESS: Introduce locked_access_point() Boqun Feng
2016-02-16  5:57 ` [RFC v2 5/6] lockdep: LOCKED_ACCESS: Add proc interface for locked access class Boqun Feng
2016-02-16  5:57 ` [RFC v2 6/6] RCU: Track rcu_dereference() in RCU read-side critical section Boqun Feng
2016-02-25 14:32 ` Peter Zijlstra [this message]
2016-02-25 15:37   ` [RFC v2 0/6] Track RCU dereferences in RCU read-side critical sections Paul E. McKenney
2016-02-26  3:06     ` Boqun Feng
2016-02-26 11:25       ` Peter Zijlstra
2016-02-29  1:12         ` Boqun Feng
2016-02-29 12:43           ` Peter Zijlstra
2016-03-01  9:32             ` Boqun Feng
2016-03-01  9:57               ` Peter Zijlstra
2016-03-01 10:01                 ` Peter Zijlstra
2016-03-02  6:37                   ` Boqun Feng
2016-03-02 10:18                     ` Peter Zijlstra
2016-03-02 14:08                       ` Paul E. McKenney

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