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From: Arnd Bergmann <arnd@arndb.de>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nick Piggin <npiggin@suse.de>,
	"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [rfc] "fair" rw spinlocks
Date: Tue, 1 Dec 2009 18:03:24 +0100	[thread overview]
Message-ID: <200912011803.24664.arnd@arndb.de> (raw)
In-Reply-To: <alpine.LFD.2.00.0911300914240.2872@localhost.localdomain>

On Monday 30 November 2009, Linus Torvalds wrote:
> The best option really would be to try to make it all use RCU, rather than 
> paper over things. That really should improve performance.

Are there any writers at interrupt time? If not, another option might be
to first convert all the readers that can happen from interrupts to RCU,
which lets us get rid of the irq disable in the write path.

Step two could either be the conversion of all nested readers to RCU,
or your tasklist_read_lock(), which should then be safe. Doing both of
these lets us turn tasklist_lock into a plain spinlock, possibly followed
by converting remaining readers that show measurable lock contention.

	Arnd <><

  reply	other threads:[~2009-12-01 17:04 UTC|newest]

Thread overview: 58+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-11-23 14:54 [rfc] "fair" rw spinlocks Nick Piggin
2009-11-24 20:19 ` David Miller
2009-11-25  6:52   ` Nick Piggin
2009-11-25  8:49   ` Andi Kleen
2009-11-25  8:56     ` Nick Piggin
2009-11-24 20:47 ` Andi Kleen
2009-11-25  6:54   ` Nick Piggin
2009-11-25  8:48     ` Andi Kleen
2009-11-25 13:09       ` Arnd Bergmann
2009-11-28  2:07 ` Paul E. McKenney
2009-11-28 11:15   ` Andi Kleen
2009-11-28 15:20     ` Paul E. McKenney
2009-11-28 17:30 ` Linus Torvalds
2009-11-29 18:51   ` Paul E. McKenney
2009-11-30  7:57     ` Nick Piggin
2009-11-30  7:55   ` Nick Piggin
2009-11-30 15:22     ` Linus Torvalds
2009-11-30 15:40       ` Nick Piggin
2009-11-30 16:07         ` Linus Torvalds
2009-11-30 16:17           ` Nick Piggin
2009-11-30 16:39           ` Paul E. McKenney
2009-11-30 17:05             ` Linus Torvalds
2009-11-30 17:13               ` Nick Piggin
2009-11-30 17:18                 ` Linus Torvalds
2009-12-01 17:03                   ` Arnd Bergmann [this message]
2009-12-01 17:15                     ` Linus Torvalds
2009-11-30 18:29                 ` Paul E. McKenney
2009-11-30 16:20     ` Paul E. McKenney
2009-11-30 10:00   ` Christoph Hellwig
2009-11-30 15:52     ` Linus Torvalds
2009-11-30 17:46       ` Ingo Molnar
2009-11-30 21:12         ` Thomas Gleixner
2009-11-30 21:27           ` Peter Zijlstra
2009-11-30 22:02             ` Thomas Gleixner
2009-11-30 22:11               ` Linus Torvalds
2009-11-30 22:37                 ` Thomas Gleixner
2009-11-30 22:49                   ` Linus Torvalds
2009-12-01 17:37                     ` [PATCH] audit: Call tty_audit_push_task() outside preempt disabled region Thomas Gleixner
2009-12-01 18:22                       ` Oleg Nesterov
2009-12-01 19:53                         ` Thomas Gleixner
2009-12-06  3:12                     ` [rfc] "fair" rw spinlocks Eric W. Biederman
2009-12-07 18:18                       ` Paul E. McKenney
2009-12-07 22:24                         ` Eric W. Biederman
2009-12-07 22:35                           ` Andi Kleen
2009-12-07 23:19                             ` Eric W. Biederman
2009-12-08  1:39                               ` Paul E. McKenney
2009-12-08  2:11                                 ` Eric W. Biederman
2009-12-08  2:37                                   ` Paul E. McKenney
2009-12-07 18:32                       ` Oleg Nesterov
2009-12-07 20:38                         ` Peter Zijlstra
2009-12-09 15:55                           ` Oleg Nesterov
2009-12-07 22:10                         ` Eric W. Biederman
2009-12-09 15:37                           ` Oleg Nesterov
2009-12-10  3:36                             ` Eric W. Biederman
2009-12-10  6:22                             ` Paul E. McKenney
2009-12-10 10:31                               ` Eric W. Biederman
2009-12-10 16:41                                 ` Paul E. McKenney
2009-12-01 19:01 ` Mathieu Desnoyers

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