From: Andi Kleen <andi@firstfloor.org>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Andi Kleen <andi@firstfloor.org>,
linux-kernel@vger.kernel.org, paulmck@linux.vnet.ibm.com
Subject: Re: [PATCH] [0/11] SYSCTL: Use RCU to avoid races with string sysctls
Date: Mon, 21 Dec 2009 04:21:04 +0100 [thread overview]
Message-ID: <20091221032104.GB25372@basil.fritz.box> (raw)
In-Reply-To: <m17hshjbwk.fsf@fess.ebiederm.org>
> So we have sysctl have locking problems, not new sysctl regressions.
Ok.
> > If the strings were made a bit smaller this could be also
> > put on the stack, but I didn't dare for 256 bytes.
>
> Hmm. rcu wise that sounds wrong, but I haven't looked into your
What sounds wrong?
The reason for the copies is that when the reader sleeps
rcu_read_lock() cannot be used to protect the string completely,
so it copies instead.
The alternative would have been to use SRCU, but I didn't like that.
> cool new data structure yet.
It's not really particularly new or cool, it's just a simple RCU wrapper
around a string.
-Andi
--
ak@linux.intel.com -- Speaking for myself only.
next prev parent reply other threads:[~2009-12-21 3:21 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-12-21 1:20 Andi Kleen
2009-12-21 1:20 ` [PATCH] [1/11] Add rcustring ADT for RCU protected strings Andi Kleen
2009-12-22 2:46 ` Paul E. McKenney
2009-12-22 10:05 ` Andi Kleen
2009-12-22 20:59 ` Paul E. McKenney
2009-12-21 1:20 ` [PATCH] [2/11] Add a kernel_address() that works for data too Andi Kleen
2009-12-21 1:20 ` [PATCH] [3/11] SYSCTL: Add proc_rcu_string to manage sysctls using rcu strings Andi Kleen
2009-12-22 2:51 ` Paul E. McKenney
2009-12-22 3:00 ` Eric W. Biederman
2009-12-22 7:44 ` Paul E. McKenney
2009-12-21 1:20 ` [PATCH] [4/11] SYSCTL: Use RCU strings for core_pattern sysctl Andi Kleen
2009-12-21 1:20 ` [PATCH] [5/11] SYSCTL: Add call_usermodehelper_cleanup() Andi Kleen
2009-12-21 1:20 ` [PATCH] [6/11] SYSCTL: Convert modprobe_path to proc_rcu_string() Andi Kleen
2009-12-21 1:20 ` [PATCH] [7/11] SYSCTL: Convert poweroff_command to proc_rcu_string Andi Kleen
2009-12-21 1:20 ` [PATCH] [8/11] SYSCTL: Convert hotplug helper string to proc_rcu_string() Andi Kleen
2009-12-22 19:03 ` Greg KH
2009-12-21 1:20 ` [PATCH] [9/11] SYSCTL: Add a mutex to the page_alloc zone order sysctl Andi Kleen
2009-12-21 1:20 ` [PATCH] [10/11] SYSCTL: Use RCU protected sysctl for ocfs group add helper Andi Kleen
2009-12-21 1:20 ` [PATCH] [11/11] SYSCTL: Convert IRDA text sysctl to RCU Andi Kleen
2009-12-21 1:59 ` [PATCH] [0/11] SYSCTL: Use RCU to avoid races with string sysctls Eric W. Biederman
2009-12-21 2:04 ` Andi Kleen
2009-12-21 2:31 ` Eric W. Biederman
2009-12-21 3:21 ` Andi Kleen [this message]
2009-12-21 7:57 Alexey Dobriyan
2009-12-21 10:50 ` Andi Kleen
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