From: Matthew Wilcox <matthew@wil.cx>
To: Linus Torvalds <torvalds@osdl.org>
Cc: Steven Rostedt <rostedt@goodmis.org>,
Joe Korty <joe.korty@ccur.com>,
Thomas Gleixner <tglx@linutronix.de>,
Geert Uytterhoeven <geert@linux-m68k.org>,
Andrew Morton <akpm@osdl.org>,
linux-arch@vger.kernel.org,
Linux Kernel Development <linux-kernel@vger.kernel.org>,
arjan@infradead.org, Christoph Hellwig <hch@infradead.org>,
mingo@elte.hu, Alan Cox <alan@lxorguk.ukuu.org.uk>,
nikita@clusterfs.com, pj@sgi.com, dhowells@redhat.com
Subject: Re: [PATCH 1/19] MUTEX: Introduce simple mutex implementation
Date: Sat, 17 Dec 2005 16:43:05 -0700 [thread overview]
Message-ID: <20051217234305.GH2361@parisc-linux.org> (raw)
In-Reply-To: <Pine.LNX.4.64.0512162323140.3698@g5.osdl.org>
On Fri, Dec 16, 2005 at 11:34:03PM -0800, Linus Torvalds wrote:
> I really can't think of any blocking kernel lock where priority
> inheritance would make _any_ sense at all. Please give me an example.
I have a better example of something we currently get wrong that I
haven't heard any RT person worry about yet. If two tasks are sleeping
on the same semaphore, the one to be woken up will be the first one to
wait for it, not the highest-priority task.
Obviously, this was introduced by the wake-one semantics. But how to
fix it? Should we scan the entire queue looking for the best task to
wake? Should we try to maintain the wait list in priority order? Or
should we just not care? Should we document that we don't care? ;-)
next prev parent reply other threads:[~2005-12-17 23:43 UTC|newest]
Thread overview: 249+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-12-12 23:45 [PATCH 1/19] MUTEX: Introduce simple mutex implementation David Howells
2005-12-12 23:45 ` [PATCH 2/19] MUTEX: i386 arch mutex David Howells
2005-12-12 23:45 ` [PATCH 8/19] MUTEX: Drivers I-K changes David Howells
2005-12-12 23:45 ` [PATCH 7/19] MUTEX: Drivers F-H changes David Howells
2005-12-12 23:45 ` [PATCH 6/19] MUTEX: Drivers A-E changes David Howells
2005-12-12 23:45 ` [PATCH 3/19] MUTEX: x86_64 arch mutex David Howells
2005-12-12 23:45 ` [PATCH 5/19] MUTEX: Core kernel changes David Howells
2005-12-12 23:45 ` [PATCH 4/19] MUTEX: FRV arch mutex David Howells
2005-12-12 23:45 ` [PATCH 15/19] MUTEX: Second set of include changes David Howells
2005-12-12 23:45 ` [PATCH 10/19] MUTEX: Drivers N-P changes David Howells
2005-12-12 23:45 ` [PATCH 9/19] MUTEX: Drivers L-M changes David Howells
2005-12-12 23:45 ` [PATCH 13/19] MUTEX: Filesystem changes David Howells
2005-12-12 23:45 ` [PATCH 14/19] MUTEX: First set of include changes David Howells
2005-12-12 23:45 ` [PATCH 12/19] MUTEX: Drivers T-Z changes David Howells
2005-12-12 23:45 ` [PATCH 11/19] MUTEX: Drivers Q-S changes David Howells
2005-12-12 23:45 ` [PATCH 18/19] MUTEX: Security changes David Howells
2005-12-12 23:45 ` [PATCH 17/19] MUTEX: Networking changes David Howells
2005-12-12 23:45 ` [PATCH 16/19] MUTEX: IPC changes David Howells
2005-12-12 23:45 ` [PATCH 19/19] MUTEX: Sound changes David Howells
2005-12-13 0:13 ` [PATCH 1/19] MUTEX: Introduce simple mutex implementation Nick Piggin
2005-12-13 0:19 ` Nick Piggin
2005-12-13 0:19 ` Andrew Morton
2005-12-13 7:54 ` Ingo Molnar
2005-12-13 7:58 ` Andi Kleen
2005-12-13 8:42 ` Andrew Morton
2005-12-13 8:49 ` Andi Kleen
2005-12-13 9:01 ` Andrew Morton
2005-12-13 9:02 ` Andrew Morton
2005-12-13 10:07 ` Jakub Jelinek
2005-12-13 10:11 ` Andi Kleen
2005-12-13 10:15 ` Jakub Jelinek
2005-12-13 10:25 ` Andrew Morton
2005-12-14 10:46 ` Russell King
2005-12-13 9:05 ` Andi Kleen
2005-12-13 9:15 ` Andrew Morton
2005-12-13 9:24 ` Andi Kleen
2005-12-13 9:44 ` Andrew Morton
2005-12-13 9:49 ` Andi Kleen
2005-12-13 10:28 ` Andreas Schwab
2005-12-13 10:30 ` Andi Kleen
2005-12-13 12:33 ` Matthew Wilcox
2005-12-13 22:18 ` Adrian Bunk
2005-12-13 22:25 ` Andi Kleen
2005-12-13 22:32 ` Adrian Bunk
2005-12-13 9:11 ` Ingo Molnar
2005-12-13 9:04 ` Christoph Hellwig
2005-12-13 9:13 ` Ingo Molnar
2005-12-13 10:11 ` Jakub Jelinek
2005-12-13 10:19 ` Christoph Hellwig
2005-12-13 10:27 ` Ingo Molnar
2005-12-15 4:53 ` Miles Bader
2005-12-15 5:05 ` Nick Piggin
2005-12-13 9:09 ` Ingo Molnar
2005-12-13 9:21 ` Andi Kleen
2005-12-13 16:16 ` Linus Torvalds
2005-12-13 21:56 ` Using C99 in the kernel was " Andi Kleen
2005-12-13 23:05 ` Al Viro
2005-12-13 23:41 ` Andi Kleen
2005-12-13 9:03 ` Christoph Hellwig
2005-12-13 9:14 ` Andrew Morton
2005-12-13 9:21 ` Christoph Hellwig
2005-12-13 10:31 ` drivers/scsi/sd.c gcc-2.95.3 Alexey Dobriyan
2005-12-13 8:00 ` [PATCH 1/19] MUTEX: Introduce simple mutex implementation Arjan van de Ven
2005-12-13 9:03 ` Ingo Molnar
2005-12-13 9:09 ` Andi Kleen
2005-12-13 9:34 ` Ingo Molnar
2005-12-13 14:33 ` Mark Lord
2005-12-13 14:45 ` Arjan van de Ven
2005-12-13 9:37 ` Ingo Molnar
2005-12-13 9:19 ` Arjan van de Ven
2005-12-13 9:02 ` Christoph Hellwig
2005-12-13 9:39 ` Ingo Molnar
2005-12-13 10:00 ` Ingo Molnar
2005-12-13 17:40 ` Paul Jackson
2005-12-13 18:34 ` David Howells
2005-12-13 22:31 ` Paul Jackson
2005-12-14 11:02 ` David Howells
2005-12-14 11:12 ` David Howells
2005-12-14 11:18 ` Alan Cox
2005-12-14 12:35 ` David Howells
2005-12-14 13:58 ` Thomas Gleixner
2005-12-14 23:40 ` Mark Lord
2005-12-14 23:54 ` Andrew Morton
2005-12-15 13:41 ` Nikita Danilov
2005-12-15 14:56 ` Alan Cox
2005-12-15 15:52 ` Nikita Danilov
2005-12-15 16:50 ` Christopher Friesen
2005-12-15 20:53 ` Steven Rostedt
2005-12-15 15:55 ` David Howells
2005-12-15 16:22 ` linux-os (Dick Johnson)
2005-12-15 16:28 ` Linus Torvalds
2005-12-15 17:04 ` Thomas Gleixner
2005-12-15 17:09 ` Paul Jackson
2005-12-15 17:17 ` David Howells
2005-12-15 16:51 ` David Howells
2005-12-15 16:56 ` Paul Jackson
2005-12-15 17:28 ` David Howells
2005-12-15 17:48 ` Linus Torvalds
2005-12-15 18:20 ` Nikita Danilov
2005-12-15 20:58 ` Steven Rostedt
2005-12-15 19:21 ` Andrew Morton
2005-12-15 19:38 ` Linus Torvalds
2005-12-15 20:28 ` Steven Rostedt
2005-12-15 20:32 ` Geert Uytterhoeven
2005-12-16 21:41 ` Thomas Gleixner
2005-12-16 21:41 ` Linus Torvalds
2005-12-16 22:06 ` Thomas Gleixner
2005-12-16 22:19 ` Linus Torvalds
2005-12-16 22:32 ` Steven Rostedt
2005-12-16 22:42 ` Thomas Gleixner
2005-12-16 22:41 ` Linus Torvalds
2005-12-16 22:49 ` Steven Rostedt
2005-12-16 23:29 ` Thomas Gleixner
2005-12-17 0:29 ` Joe Korty
2005-12-17 1:00 ` Linus Torvalds
2005-12-17 3:13 ` Steven Rostedt
2005-12-17 7:34 ` Linus Torvalds
2005-12-17 23:43 ` Matthew Wilcox [this message]
2005-12-18 0:05 ` Lee Revell
2005-12-18 0:21 ` Matthew Wilcox
2005-12-18 1:25 ` Lee Revell
2005-12-22 12:27 ` Bill Huey
2005-12-19 16:08 ` Ingo Molnar
2005-12-22 12:40 ` Bill Huey
2005-12-22 12:45 ` Bill Huey
2005-12-19 23:46 ` Keith Owens
2005-12-15 14:41 ` Steven Rostedt
2005-12-14 23:57 ` Thomas Gleixner
2005-12-14 23:57 ` Mark Lord
2005-12-15 0:10 ` Thomas Gleixner
2005-12-15 2:46 ` Linus Torvalds
2005-12-15 15:53 ` David Howells
2005-12-15 15:37 ` David Howells
2005-12-15 19:28 ` Andrew Morton
2005-12-15 20:18 ` Andrew Morton
2005-12-15 21:28 ` Steven Rostedt
2005-12-16 22:02 ` Thomas Gleixner
2005-12-16 10:45 ` David Howells
2005-12-13 9:55 ` Ingo Molnar
2005-12-13 0:30 ` Arnd Bergmann
2005-12-13 0:57 ` Daniel Walker
2005-12-13 3:23 ` Steven Rostedt
2005-12-13 2:57 ` Mark Lord
2005-12-13 3:17 ` Steven Rostedt
2005-12-13 9:06 ` Christoph Hellwig
2005-12-13 9:54 ` David Howells
2005-12-13 10:13 ` Ingo Molnar
2005-12-13 10:34 ` Ingo Molnar
2005-12-13 10:37 ` Ingo Molnar
2005-12-13 12:47 ` Oliver Neukum
2005-12-13 13:09 ` Alan Cox
2005-12-13 13:13 ` Matthew Wilcox
2005-12-13 14:04 ` Alan Cox
2005-12-13 13:24 ` Oliver Neukum
2005-12-14 1:00 ` Nick Piggin
2005-12-14 10:54 ` David Howells
2005-12-14 11:17 ` Nick Piggin
2005-12-14 11:46 ` David Howells
2005-12-14 21:23 ` Nick Piggin
2005-12-16 12:00 ` David Howells
2005-12-16 13:16 ` Nick Piggin
2005-12-16 15:53 ` David Howells
2005-12-16 23:41 ` Nick Piggin
2005-12-16 16:02 ` David Howells
2005-12-13 10:48 ` David Howells
2005-12-13 12:39 ` Matthew Wilcox
2005-12-13 10:54 ` Ingo Molnar
2005-12-13 11:23 ` David Howells
2005-12-13 11:24 ` David Howells
2005-12-13 13:45 ` Ingo Molnar
2005-12-13 11:34 ` David Howells
2005-12-13 13:05 ` Alan Cox
2005-12-13 13:15 ` Alan Cox
2005-12-13 23:21 ` Nikita Danilov
2005-12-13 13:32 ` David Howells
2005-12-13 14:00 ` Alan Cox
2005-12-13 14:35 ` Christopher Friesen
2005-12-13 14:44 ` Arjan van de Ven
2005-12-13 14:59 ` Christopher Friesen
2005-12-13 15:23 ` David Howells
2005-12-15 5:24 ` Miles Bader
2005-12-13 15:39 ` David Howells
2005-12-13 16:10 ` Alan Cox
2005-12-14 10:29 ` Arjan van de Ven
2005-12-14 11:03 ` Arjan van de Ven
2005-12-14 11:03 ` Alan Cox
2005-12-14 11:08 ` Arjan van de Ven
2005-12-14 11:24 ` Alan Cox
2005-12-14 11:35 ` Andrew Morton
2005-12-14 11:44 ` Arjan van de Ven
2005-12-14 11:52 ` Andi Kleen
2005-12-14 11:55 ` Arjan van de Ven
2005-12-14 11:57 ` David Howells
2005-12-14 12:19 ` Jakub Jelinek
2005-12-16 1:54 ` Nick Piggin
2005-12-16 11:02 ` David Howells
2005-12-16 13:01 ` Nick Piggin
2005-12-16 13:21 ` Russell King
2005-12-16 13:41 ` Nick Piggin
2005-12-16 13:46 ` Linh Dang
2005-12-16 14:31 ` Russell King
2005-12-16 15:24 ` Linh Dang
2005-12-16 15:35 ` Nick Piggin
2005-12-16 15:40 ` Kyle Moffett
2005-12-16 15:49 ` Linh Dang
2005-12-16 15:46 ` David Howells
2005-12-16 15:58 ` Russell King
2005-12-17 15:57 ` Nikita Danilov
2005-12-16 16:28 ` Linus Torvalds
2005-12-16 11:30 ` David Howells
2005-12-16 16:33 ` Linus Torvalds
2005-12-16 22:23 ` David S. Miller
2005-12-16 22:38 ` Linus Torvalds
2005-12-16 22:53 ` David S. Miller
2005-12-17 0:41 ` Jesse Barnes
2005-12-17 7:10 ` David S. Miller
2005-12-17 7:40 ` Linus Torvalds
2005-12-17 17:22 ` Jesse Barnes
2005-12-17 17:19 ` Jesse Barnes
2005-12-17 22:38 ` Richard Henderson
2005-12-17 23:05 ` David S. Miller
2005-12-14 12:17 ` Christoph Hellwig
2005-12-14 11:42 ` Arjan van de Ven
2005-12-14 8:31 ` Ingo Molnar
2005-12-13 20:04 ` Steven Rostedt
2005-12-13 21:03 ` David Howells
2005-12-15 13:58 linux
2005-12-15 16:15 ` Linus Torvalds
2005-12-15 16:52 ` Erik Mouw
2005-12-15 17:23 ` Dick Streefland
2005-12-16 12:17 ` Erik Mouw
2005-12-17 10:59 ` Sander
2005-12-17 14:14 ` Douglas McNaught
2005-12-17 15:09 ` Sander
2005-12-19 10:44 ` Erik Mouw
2005-12-15 19:02 ` Nikita Danilov
2005-12-15 19:09 ` linux
2005-12-15 19:52 ` Linus Torvalds
2005-12-16 1:33 ` linux
2005-12-15 21:18 ` Steven Rostedt
2005-12-15 20:52 ` Steven Rostedt
2005-12-15 17:45 Luck, Tony
2005-12-15 18:00 ` David Howells
2005-12-15 18:48 ` James Bottomley
2005-12-15 20:38 ` Jeff Dike
2005-12-15 23:45 ` Stephen Rothwell
2005-12-16 12:49 linux
2005-12-16 15:24 ` David Howells
2005-12-16 18:03 ` linux
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