From: Nick Piggin <npiggin@suse.de>
To: "Paul E. McKenney" <paulmck@us.ibm.com>
Cc: Andrew Morton <akpm@osdl.org>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul McKenney <Paul.McKenney@us.ibm.com>,
Linux Kernel <linux-kernel@vger.kernel.org>
Subject: Userspace RCU+rtth hack (was Re: [patch 3/3] radix-tree: RCU lockless readside)
Date: Thu, 22 Jun 2006 20:23:43 +0200 [thread overview]
Message-ID: <20060622182343.GA29003@wotan.suse.de> (raw)
In-Reply-To: <20060622174057.GF1295@us.ibm.com>
[-- Attachment #1: Type: text/plain, Size: 724 bytes --]
Just out of interest, attached is my userspace RCU implementation
and RCU radix-tree concurrent tests for Andrew Morton's radix-tree
test harness.
The RCU implementation is only 100 lines. Awful performance, of
course, but I've stretched the rcu_read_lock/unlock over large
periods so that we can get full concurrency at the cost of a
bit of memory build up. And it still seems to catch use-after
RCU-freed errors pretty easily.
Question - our kernel's call_rcu implies a smp_wmb, right? Because
that did catch me out initially, because I initially had no barrier
to prevent the freeing of the object becoming visible before
removal of its last reference becoming visible (fixed by adding
smp_wmb() in my call_rcu).
Nick
[-- Attachment #2: rtth.tar.gz --]
[-- Type: application/x-gunzip, Size: 21868 bytes --]
next prev parent reply other threads:[~2006-06-22 18:23 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-06-20 14:48 [patch 0/3] 2.6.17 radix-tree: updates and lockless Nick Piggin
2006-06-20 14:48 ` [patch 1/3] radix-tree: direct data Nick Piggin
2006-06-20 14:48 ` [patch 2/3] radix-tree: small Nick Piggin
2006-06-20 14:48 ` [patch 3/3] radix-tree: RCU lockless readside Nick Piggin
2006-06-22 1:49 ` Paul E. McKenney
2006-06-22 15:45 ` Nick Piggin
2006-06-22 16:30 ` Paul E. McKenney
[not found] ` <20060622165551.GB23109@wotan.suse.de>
[not found] ` <20060622174057.GF1295@us.ibm.com>
2006-06-22 18:11 ` Nick Piggin
2006-06-23 7:09 ` Andrew Morton
2006-06-23 8:03 ` Nick Piggin
2006-06-23 8:39 ` Nick Piggin
2006-06-23 8:41 ` Nick Piggin
2006-06-22 18:23 ` Nick Piggin [this message]
2006-06-22 20:25 ` Userspace RCU+rtth hack (was Re: [patch 3/3] radix-tree: RCU lockless readside) Paul E. McKenney
2006-06-24 10:20 ` Nick Piggin
2006-06-24 15:55 ` Joe Seigh
2006-06-20 22:08 ` [patch 0/3] 2.6.17 radix-tree: updates and lockless Benjamin Herrenschmidt
2006-06-20 22:35 ` Andrew Morton
2006-06-20 23:09 ` Benjamin Herrenschmidt
2006-06-20 23:30 ` Andrew Morton
2006-06-20 23:50 ` Benjamin Herrenschmidt
2006-06-21 0:34 ` Christoph Lameter
2006-06-21 0:47 ` Benjamin Herrenschmidt
2006-06-21 1:07 ` Christoph Lameter
2006-06-21 1:33 ` Benjamin Herrenschmidt
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