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From: Russell King - ARM Linux <linux@arm.linux.org.uk>
To: Ingo Molnar <mingo@elte.hu>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Marc Zyngier <Marc.Zyngier@arm.com>,
	Frank Rowand <frank.rowand@am.sony.com>,
	Oleg Nesterov <oleg@redhat.com>,
	linux-kernel@vger.kernel.org, Yong Zhang <yong.zhang0@gmail.com>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [BUG] "sched: Remove rq->lock from the first half of ttwu()" locks up on ARM
Date: Fri, 27 May 2011 18:55:00 +0100	[thread overview]
Message-ID: <20110527175500.GQ24876@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <20110527120629.GA32617@elte.hu>

On Fri, May 27, 2011 at 02:06:29PM +0200, Ingo Molnar wrote:
> I'd suggest doing this once modern ARM chips get so widespread that 
> you can realistically induce a ~700 usecs irqs-off delays on old, 
> virtual-cache ARM chips. Old chips would likely use old kernels 
> anyway, right?

Not necessarily.  I have rather a lot of legacy hardware (it outweighs
the more modern stuff) and that legacy hardware is _loads_ more useful
than the modern stuff in that it can actually do stuff like run a network
(such as running kerberos servers, httpd, mtas, etc).  Modern ARM
machines typically don't have ways to attach mass storage to them which
make them hellishly limited for such applications.

I'm planning to continue using my old machines, and continue to upgrade
their kernels, especially in order to keep up to date with security
issues.

WARNING: multiple messages have this Message-ID (diff)
From: linux@arm.linux.org.uk (Russell King - ARM Linux)
To: linux-arm-kernel@lists.infradead.org
Subject: [BUG] "sched: Remove rq->lock from the first half of ttwu()" locks up on ARM
Date: Fri, 27 May 2011 18:55:00 +0100	[thread overview]
Message-ID: <20110527175500.GQ24876@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <20110527120629.GA32617@elte.hu>

On Fri, May 27, 2011 at 02:06:29PM +0200, Ingo Molnar wrote:
> I'd suggest doing this once modern ARM chips get so widespread that 
> you can realistically induce a ~700 usecs irqs-off delays on old, 
> virtual-cache ARM chips. Old chips would likely use old kernels 
> anyway, right?

Not necessarily.  I have rather a lot of legacy hardware (it outweighs
the more modern stuff) and that legacy hardware is _loads_ more useful
than the modern stuff in that it can actually do stuff like run a network
(such as running kerberos servers, httpd, mtas, etc).  Modern ARM
machines typically don't have ways to attach mass storage to them which
make them hellishly limited for such applications.

I'm planning to continue using my old machines, and continue to upgrade
their kernels, especially in order to keep up to date with security
issues.

  reply	other threads:[~2011-05-27 17:55 UTC|newest]

Thread overview: 102+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-05-24 18:13 [BUG] "sched: Remove rq->lock from the first half of ttwu()" locks up on ARM Marc Zyngier
2011-05-24 18:13 ` Marc Zyngier
2011-05-24 21:32 ` Peter Zijlstra
2011-05-24 21:32   ` Peter Zijlstra
2011-05-24 21:39   ` Ingo Molnar
2011-05-24 21:39     ` Ingo Molnar
2011-05-25 12:23     ` Marc Zyngier
2011-05-25 12:23       ` Marc Zyngier
2011-05-25 17:08   ` Peter Zijlstra
2011-05-25 17:08     ` Peter Zijlstra
2011-05-25 21:15     ` Peter Zijlstra
2011-05-25 21:15       ` Peter Zijlstra
2011-05-26  7:29       ` Yong Zhang
2011-05-26  7:29         ` Yong Zhang
2011-05-26 10:32         ` Peter Zijlstra
2011-05-26 10:32           ` Peter Zijlstra
2011-05-26 11:02           ` Marc Zyngier
2011-05-26 11:02             ` Marc Zyngier
2011-05-26 11:32             ` Peter Zijlstra
2011-05-26 11:32               ` Peter Zijlstra
2011-05-26 12:21               ` Peter Zijlstra
2011-05-26 12:21                 ` Peter Zijlstra
2011-05-26 12:26                 ` Ingo Molnar
2011-05-26 12:26                   ` Ingo Molnar
2011-05-26 12:31                   ` Russell King - ARM Linux
2011-05-26 12:31                     ` Russell King - ARM Linux
2011-05-26 12:37                     ` Peter Zijlstra
2011-05-26 12:37                       ` Peter Zijlstra
2011-05-26 12:50                     ` Ingo Molnar
2011-05-26 12:50                       ` Ingo Molnar
2011-05-26 13:36                       ` Russell King - ARM Linux
2011-05-26 13:36                         ` Russell King - ARM Linux
2011-05-26 14:45                       ` Catalin Marinas
2011-05-26 14:45                         ` Catalin Marinas
2011-05-27 12:06                         ` Ingo Molnar
2011-05-27 12:06                           ` Ingo Molnar
2011-05-27 17:55                           ` Russell King - ARM Linux [this message]
2011-05-27 17:55                             ` Russell King - ARM Linux
2011-05-27 19:41                           ` Nicolas Pitre
2011-05-27 19:41                             ` Nicolas Pitre
2011-05-27 20:52                           ` Russell King - ARM Linux
2011-05-27 20:52                             ` Russell King - ARM Linux
2011-05-28 13:13                             ` Peter Zijlstra
2011-05-28 13:13                               ` Peter Zijlstra
2011-05-31 11:08                               ` Michal Simek
2011-05-31 11:08                                 ` Michal Simek
2011-05-31 13:22                                 ` Peter Zijlstra
2011-05-31 13:22                                   ` Peter Zijlstra
2011-05-31 13:37                                   ` Michal Simek
2011-05-31 13:37                                     ` Michal Simek
2011-05-31 13:52                                     ` Peter Zijlstra
2011-05-31 13:52                                       ` Peter Zijlstra
2011-05-31 14:08                                       ` Michal Simek
2011-05-31 14:08                                         ` Michal Simek
2011-05-31 14:29                                         ` Peter Zijlstra
2011-05-31 14:29                                           ` Peter Zijlstra
2011-05-29 10:21                             ` Catalin Marinas
2011-05-29 10:21                               ` Catalin Marinas
2011-05-29 10:26                               ` Russell King - ARM Linux
2011-05-29 10:26                                 ` Russell King - ARM Linux
2011-05-29 12:01                                 ` Catalin Marinas
2011-05-29 12:01                                   ` Catalin Marinas
2011-05-29 13:19                                   ` Russell King - ARM Linux
2011-05-29 13:19                                     ` Russell King - ARM Linux
2011-05-29 21:21                                     ` Catalin Marinas
2011-05-29 21:21                                       ` Catalin Marinas
2011-05-29  9:51                           ` Catalin Marinas
2011-05-29  9:51                             ` Catalin Marinas
2011-06-06 10:29                           ` Pavel Machek
2011-06-06 10:29                             ` Pavel Machek
2011-05-26 14:56                 ` Marc Zyngier
2011-05-26 14:56                   ` Marc Zyngier
2011-05-26 15:45                 ` Oleg Nesterov
2011-05-26 15:45                   ` Oleg Nesterov
2011-05-26 15:59                   ` Peter Zijlstra
2011-05-26 15:59                     ` Peter Zijlstra
2011-05-26 16:09                     ` Peter Zijlstra
2011-05-26 16:09                       ` Peter Zijlstra
2011-05-26 16:20                       ` Marc Zyngier
2011-05-26 16:20                         ` Marc Zyngier
2011-05-26 16:32                         ` Peter Zijlstra
2011-05-26 16:32                           ` Peter Zijlstra
2011-05-27  8:01                           ` Marc Zyngier
2011-05-27  8:01                             ` Marc Zyngier
2011-05-26 16:22                       ` Marc Zyngier
2011-05-26 16:22                         ` Marc Zyngier
2011-05-26 17:04                       ` Oleg Nesterov
2011-05-26 17:04                         ` Oleg Nesterov
2011-05-26 17:17                         ` Peter Zijlstra
2011-05-26 17:17                           ` Peter Zijlstra
2011-05-26 17:23                           ` Peter Zijlstra
2011-05-26 17:23                             ` Peter Zijlstra
2011-05-26 17:49                             ` Oleg Nesterov
2011-05-26 17:49                               ` Oleg Nesterov
2011-05-27  7:01                             ` Yong Zhang
2011-05-27  7:01                               ` Yong Zhang
2011-05-27 15:23                             ` Santosh Shilimkar
2011-05-27 15:23                               ` Santosh Shilimkar
2011-05-27 15:29                               ` Marc Zyngier
2011-05-27 15:29                                 ` Marc Zyngier
2011-05-27 15:30                                 ` Santosh Shilimkar
2011-05-27 15:30                                   ` Santosh Shilimkar

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