From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Andi Kleen <ak@linux.intel.com>, Andi Kleen <andi@firstfloor.org>,
x86@kernel.org, linux-kernel@vger.kernel.org, oleg@redhat.com,
rusty@rustcorp.com.au, mingo@kernel.org
Subject: Re: [RFC][PATCH] module: Optimize __module_address() using a latched RB-tree
Date: Mon, 2 Mar 2015 08:58:12 -0800 [thread overview]
Message-ID: <20150302165811.GP15405@linux.vnet.ibm.com> (raw)
In-Reply-To: <20150302092440.GF5029@twins.programming.kicks-ass.net>
On Mon, Mar 02, 2015 at 10:24:40AM +0100, Peter Zijlstra wrote:
> On Sat, Feb 28, 2015 at 03:32:03PM -0800, Paul E. McKenney wrote:
> > Whew!
> >
> > Though otherwise whatever you were doing would have been pretty cool
> > and fun to learn about. ;-)
>
> So I think I can do that; where readers and writers are fully separated,
> but it requires:
>
> - tripple latch
> - copy operator
> - nested RCU
>
> And the result would be horribly expensive (mostly due to the copy
> operator on dynamic data structures) on the update side, which severely
> limits the applicability of the scheme.
True enough, if you have a single pointer to an RCU-protected data
structure, you can update anything in any way by doing a deep copy of
the original, updating, and swapping pointers. And what is a little
copy overhead among friends? ;-)
Thanx, Paul
next prev parent reply other threads:[~2015-03-02 16:58 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-21 1:38 [PATCH 1/3] x86: Move msr accesses out of line Andi Kleen
2015-02-21 1:38 ` [PATCH 2/3] x86: Add trace point for MSR accesses Andi Kleen
2015-02-21 1:38 ` [PATCH 3/3] perf, x86: Remove old MSR perf tracing code Andi Kleen
2015-02-23 17:04 ` [PATCH 1/3] x86: Move msr accesses out of line Peter Zijlstra
2015-02-23 17:43 ` Andi Kleen
2015-02-25 12:27 ` Peter Zijlstra
2015-02-25 18:20 ` Andi Kleen
2015-02-25 18:34 ` Borislav Petkov
2015-02-26 11:43 ` [RFC][PATCH] module: Optimize __module_address() using a latched RB-tree Peter Zijlstra
2015-02-26 12:00 ` Ingo Molnar
2015-02-26 14:12 ` Peter Zijlstra
2015-02-27 11:51 ` Rusty Russell
2015-02-26 16:02 ` Mathieu Desnoyers
2015-02-26 16:43 ` Peter Zijlstra
2015-02-26 16:55 ` Mathieu Desnoyers
2015-02-26 17:16 ` Peter Zijlstra
2015-02-26 17:22 ` Peter Zijlstra
2015-02-26 18:28 ` Paul E. McKenney
2015-02-26 19:06 ` Mathieu Desnoyers
2015-02-26 19:13 ` Peter Zijlstra
2015-02-26 19:41 ` Paul E. McKenney
2015-02-26 19:45 ` Peter Zijlstra
2015-02-26 22:32 ` Peter Zijlstra
2015-02-26 20:52 ` Andi Kleen
2015-02-26 22:36 ` Peter Zijlstra
2015-02-27 10:01 ` Peter Zijlstra
2015-02-28 23:30 ` Paul E. McKenney
2015-02-28 16:41 ` Peter Zijlstra
2015-02-28 16:56 ` Peter Zijlstra
2015-02-28 23:32 ` Paul E. McKenney
2015-03-02 9:24 ` Peter Zijlstra
2015-03-02 16:58 ` Paul E. McKenney [this message]
2015-02-27 12:02 ` Rusty Russell
2015-02-27 14:30 ` Peter Zijlstra
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