From: Peter Zijlstra <peterz@infradead.org>
To: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Josh Triplett <josh@joshtriplett.org>,
linux-kernel@vger.kernel.org, mingo@elte.hu,
laijs@cn.fujitsu.com, dipankar@in.ibm.com,
akpm@linux-foundation.org, mathieu.desnoyers@polymtl.ca,
niv@us.ibm.com, tglx@linutronix.de, rostedt@goodmis.org,
Valdis.Kletnieks@vt.edu, dhowells@redhat.com,
edumazet@google.com, darren@dvhart.com, fweisbec@gmail.com,
sbw@mit.edu
Subject: Re: [PATCH tip/core/rcu 6/7] rcu: Drive quiescent-state-forcing delay from HZ
Date: Tue, 14 May 2013 16:51:20 +0200 [thread overview]
Message-ID: <20130514145119.GC19669@dyad.programming.kicks-ass.net> (raw)
In-Reply-To: <20130514141245.GA4442@linux.vnet.ibm.com>
> In theory, yes. In practice, this requires lots of lock acquisitions
> and releases on large systems, including some global locks. The weight
> could be reduced, but...
>
> What I would like to do instead would be to specify expedited grace
> periods during boot.
But why, surely going idle without any RCU callbacks isn't completely unheard
of, even outside of the boot process?
Being able to quickly drop out of the RCU state machinery would be a good thing IMO.
> The challenge here appears to be somehow telling
> RCU when boot is done. The APIs are there from an RCU viewpoint: boot
> with rcupdate.rcu_expedited=1, then, once boot is complete (whatever
> that means on your platform) "echo 0 > /sys/kernel/rcu_expedited".
Ha, and here you assume userspace is sane and co-operative. Fail in my book ;-)
next prev parent reply other threads:[~2013-05-14 14:53 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-04-12 23:18 [PATCH tip/core/rcu 0/7] RCU fixes for 3.11 Paul E. McKenney
2013-04-12 23:19 ` [PATCH tip/core/rcu 1/7] rcu: Convert rcutree.c printk calls Paul E. McKenney
2013-04-12 23:19 ` [PATCH tip/core/rcu 2/7] rcu: Convert rcutree_plugin.h " Paul E. McKenney
2013-04-12 23:19 ` [PATCH tip/core/rcu 3/7] rcu: Kick adaptive-ticks CPUs that are holding up RCU grace periods Paul E. McKenney
2013-04-13 14:06 ` Frederic Weisbecker
2013-04-13 15:19 ` Paul E. McKenney
2013-04-12 23:19 ` [PATCH tip/core/rcu 4/7] rcu: Don't allocate bootmem from rcu_init() Paul E. McKenney
2013-04-12 23:19 ` [PATCH tip/core/rcu 5/7] rcu: Remove "Experimental" flags Paul E. McKenney
2013-04-12 23:19 ` [PATCH tip/core/rcu 6/7] rcu: Drive quiescent-state-forcing delay from HZ Paul E. McKenney
2013-04-12 23:54 ` Josh Triplett
2013-04-13 6:38 ` Paul E. McKenney
2013-04-13 18:18 ` Josh Triplett
2013-04-13 19:34 ` Paul E. McKenney
2013-04-13 19:53 ` Josh Triplett
2013-04-13 22:09 ` Paul E. McKenney
2013-04-14 6:10 ` Paul E. McKenney
2013-05-14 12:20 ` Peter Zijlstra
2013-05-14 14:12 ` Paul E. McKenney
2013-05-14 14:51 ` Peter Zijlstra [this message]
2013-05-14 15:47 ` Paul E. McKenney
2013-05-15 8:56 ` Peter Zijlstra
2013-05-15 9:02 ` Peter Zijlstra
2013-05-15 17:31 ` Paul E. McKenney
2013-05-16 9:45 ` Peter Zijlstra
2013-05-16 13:22 ` Paul E. McKenney
2013-05-21 9:45 ` Peter Zijlstra
2013-05-21 16:54 ` Paul E. McKenney
2013-05-15 16:37 ` Paul E. McKenney
2013-05-16 9:37 ` Peter Zijlstra
2013-05-16 13:13 ` Paul E. McKenney
2013-05-15 9:20 ` Ingo Molnar
2013-05-15 15:44 ` Paul E. McKenney
2013-05-28 10:07 ` Ingo Molnar
2013-05-29 1:29 ` Paul E. McKenney
2013-04-15 2:03 ` Paul Mackerras
2013-04-15 17:26 ` Paul E. McKenney
2013-04-12 23:19 ` [PATCH tip/core/rcu 7/7] rcu: Merge adjacent identical ifdefs Paul E. McKenney
2013-04-13 0:01 ` [PATCH tip/core/rcu 0/7] RCU fixes for 3.11 Josh Triplett
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