From: Ingo Molnar <mingo@elte.hu>
To: "Paul E. McKenney" <paulmck@us.ibm.com>
Cc: dipankar@in.ibm.com, shemminger@osdl.org, akpm@osdl.org,
torvalds@osdl.org, rusty@au1.ibm.com, tgall@us.ibm.com,
jim.houston@comcast.net, manfred@colorfullife.com, gh@us.ibm.com,
linux-kernel@vger.kernel.org
Subject: Re: Real-Time Preemption and RCU
Date: Fri, 18 Mar 2005 10:53:27 +0100 [thread overview]
Message-ID: <20050318095327.GA15190@elte.hu> (raw)
In-Reply-To: <20050318092816.GA12032@elte.hu>
* Ingo Molnar <mingo@elte.hu> wrote:
> there's one detail on PREEMPT_RT though (which i think you noticed too).
>
> Priority inheritance handling can be done in a pretty straightforward
> way as long as no true read-side nesting is allowed for rwsems and
> rwlocks - i.e. there's only one owner of a lock at a time. So
> PREEMPT_RT restricts rwsem and rwlock concurrency: readers are
> writers, with the only exception that they are allowed to 'self-nest'.
> [...]
this does not affect read-side RCU, because read-side RCU can never
block a higher-prio thread. (as long as callback processing is pushed
into a separate kernel thread.)
so RCU will be pretty much the only mechanism (besides lock-free code)
that allows reader concurrency on PREEMPT_RT.
Ingo
next prev parent reply other threads:[~2005-03-18 9:53 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-03-18 0:20 Real-Time Preemption and RCU Paul E. McKenney
2005-03-18 7:49 ` Ingo Molnar
2005-03-18 16:43 ` Paul E. McKenney
2005-03-18 17:11 ` Ingo Molnar
2005-03-18 17:29 ` Paul E. McKenney
2005-03-18 20:35 ` Paul E. McKenney
2005-03-18 22:22 ` Paul E. McKenney
2005-03-19 0:48 ` Paul E. McKenney
2005-03-18 8:44 ` Ingo Molnar
2005-03-18 9:04 ` Ingo Molnar
2005-03-18 9:38 ` Ingo Molnar
2005-03-18 9:13 ` Ingo Molnar
2005-03-18 9:28 ` Ingo Molnar
2005-03-18 9:53 ` Ingo Molnar [this message]
2005-03-18 15:33 ` Paul E. McKenney
2005-03-19 5:03 ` Manfred Spraul
2005-03-19 16:26 ` Ingo Molnar
2005-03-20 6:36 ` Manfred Spraul
2005-03-20 9:25 ` Thomas Gleixner
2005-03-20 16:57 ` Manfred Spraul
2005-03-20 21:38 ` Bill Huey
2005-03-20 21:59 ` Bill Huey
2005-03-18 10:03 ` Ingo Molnar
2005-03-18 11:30 ` Ingo Molnar
2005-03-18 16:48 ` Esben Nielsen
2005-03-18 17:19 ` Ingo Molnar
2005-03-20 13:29 ` Esben Nielsen
2005-03-20 22:38 ` Paul E. McKenney
2005-03-20 23:23 ` Esben Nielsen
2005-03-22 5:53 ` Paul E. McKenney
2005-03-22 8:55 ` Esben Nielsen
2005-03-22 9:20 ` Ingo Molnar
2005-03-22 10:19 ` Esben Nielsen
2005-03-23 5:40 ` Paul E. McKenney
2005-03-23 11:44 ` Esben Nielsen
2005-03-24 7:02 ` Paul E. McKenney
2005-03-22 10:56 ` Ingo Molnar
2005-03-22 11:39 ` Esben Nielsen
2005-03-22 13:10 ` Ingo Molnar
2005-03-22 15:08 ` Esben Nielsen
2005-03-18 15:48 ` Paul E. McKenney
2005-03-18 11:38 ` Ingo Molnar
2005-03-18 12:56 ` Bill Huey
2005-03-18 13:17 ` Bill Huey
2005-03-18 15:57 ` Paul E. McKenney
2005-03-18 16:02 ` Ingo Molnar
2005-03-18 16:55 ` Esben Nielsen
2005-03-22 10:04 ` Bill Huey
2005-03-22 10:17 ` Bill Huey
2005-03-22 10:34 ` Bill Huey
2005-03-22 10:38 ` Esben Nielsen
2005-03-18 22:26 ` Herbert Xu
2005-03-19 16:31 ` Ingo Molnar
2005-03-20 8:01 ` Kyle Moffett
2005-03-22 8:08 ` Ingo Molnar
2005-03-18 15:54 ` Paul E. McKenney
2005-03-18 15:58 ` Ingo Molnar
2009-06-11 22:57 real-time preemption " James Huang
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