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From: Ingo Molnar <mingo@elte.hu>
To: davidm@hpl.hp.com
Cc: "Luck, Tony" <tony.luck@intel.com>, linux-kernel@vger.kernel.org
Subject: Re: [patch] sched: unlocked context-switches
Date: Sat, 9 Apr 2005 09:07:38 +0200	[thread overview]
Message-ID: <20050409070738.GA5444@elte.hu> (raw)
In-Reply-To: <ugoecowjci.fsf@panda.mostang.com>


* David Mosberger-Tang <David.Mosberger@acm.org> wrote:

>  > The ia64_switch_to() code includes a section that can change a
>  > pinned MMU mapping (when the stack for the new process is in a
>  > different granule from the stack for the old process).  The code
>  > beyond the ".map" label in arch/ia64/kernel/entry.S includes the
>  > comment:
> 
> Also, there was a nasty dead-lock that could trigger if the 
> context-switch was interrupted by a TLB flush IPI.  I don't remember 
> the details offhand, but I'm pretty sure it had to do with 
> switch_mm(), so I suspect it may not be enough to disable irqs just 
> for ia64_switch_to().  Tread with care!

we'll see. The patch certainly needs more testing. Generally we do 
switch_mm()'s outside of the scheduler as well, without disabling 
interrupts.

	Ingo

  reply	other threads:[~2005-04-09  7:08 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <3R6Ir-89Y-23@gated-at.bofh.it>
2005-04-09  6:32 ` [patch] sched: unlocked context-switches David Mosberger-Tang
2005-04-09  7:07   ` Ingo Molnar [this message]
2005-04-09  7:15     ` David Mosberger
2005-04-09 22:58       ` David S. Miller
2005-04-10  6:43         ` Ingo Molnar
2005-04-12  1:06           ` David Mosberger
2005-04-12  2:12             ` Nick Piggin
2005-04-12 17:14               ` David Mosberger
2005-04-13  3:26                 ` Nick Piggin
2005-04-12  6:42             ` Ingo Molnar
2005-04-12 17:15               ` David Mosberger
2005-04-08 18:38 Luck, Tony
2005-04-09  4:38 ` Ingo Molnar
2005-04-09  6:28   ` Nick Piggin
2005-04-09  6:55     ` Ingo Molnar
2005-04-09  7:11       ` Nick Piggin
2005-04-09  9:22   ` Benjamin Herrenschmidt
2005-04-09 22:46     ` David S. Miller
2005-04-10  7:23       ` Richard Henderson
  -- strict thread matches above, loose matches on Subject: below --
2005-04-08 12:16 Ingo Molnar
2005-04-29  9:09 ` Andrew Morton

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