From: Rusty Russell <rusty@rustcorp.com.au>
To: "Peter Wächtler" <pwaechtler@loewe-komp.de>
Cc: frankeh@watson.ibm.com, arjanv@redhat.com, linux-kernel@vger.kernel.org
Subject: Re: furwocks: Fast Userspace Read/Write Locks
Date: Sat, 09 Mar 2002 15:50:37 +1100 [thread overview]
Message-ID: <E16jYor-0003Ty-00@wagner.rustcorp.com.au> (raw)
In-Reply-To: Your message of "Fri, 08 Mar 2002 10:21:08 BST." <3C888284.8030206@loewe-komp.de>
In message <3C888284.8030206@loewe-komp.de> you write:
> Rusty Russell wrote:
> > To clarify: I'd love this, but rwlocks in the kernel aren't even
> > vaguely fair. With a steady stream of overlapping readers, a writer
> > will never get the lock.
> >
> > Hope that clarifies,
>
>
> But you talk about the current implementation, don't you?
> Is there something to prevent an implementation of rwlocks in the
> kernel, where a wrlock will lock (postponed) further rdlock requests?
It's proven hard to do without performance impact. Also, we can't do
rw semaphores in a single word: you need two.
Disproving me by implementation VERY welcome!
Hope that helps,
Rusty.
--
Anyone who quotes me in their sig is an idiot. -- Rusty Russell.
next prev parent reply other threads:[~2002-03-09 7:14 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-03-07 12:11 Rusty Russell
2002-03-07 12:40 ` Peter Wächtler
2002-03-07 14:41 ` Hubertus Franke
2002-03-07 12:50 ` Arjan van de Ven
2002-03-07 15:33 ` Hubertus Franke
2002-03-07 15:42 ` Arjan van de Ven
2002-03-07 19:11 ` Hubertus Franke
2002-03-07 20:17 ` H. Peter Anvin
2002-03-08 6:27 ` Rusty Russell
2002-03-08 6:29 ` H. Peter Anvin
2002-03-08 7:09 ` Rusty Russell
2002-03-08 19:32 ` Jamie Lokier
2002-03-08 1:22 ` Rusty Russell
2002-03-08 3:26 ` H. Peter Anvin
2002-03-08 9:21 ` Peter Wächtler
2002-03-08 18:13 ` Hubertus Franke
2002-03-09 4:50 ` Rusty Russell [this message]
2002-03-11 18:47 ` Hubertus Franke
2002-03-07 15:28 ` Hubertus Franke
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