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From: Russell King <rmk+lkml@arm.linux.org.uk>
To: Andi Kleen <ak@muc.de>
Cc: William Lee Irwin III <wli@holomorphy.com>,
	Albert Cahalan <albert@users.sf.net>,
	Jakub Jelinek <jakub@redhat.com>,
	Albert Cahalan <albert@users.sourceforge.net>,
	linux-kernel mailing list <linux-kernel@vger.kernel.org>
Subject: Re: get_current is __pure__, maybe __const__ even
Date: Thu, 16 Sep 2004 15:36:16 +0100	[thread overview]
Message-ID: <20040916153616.D31029@flint.arm.linux.org.uk> (raw)
In-Reply-To: <20040916110355.GA20448@muc.de>; from ak@muc.de on Thu, Sep 16, 2004 at 01:03:55PM +0200

On Thu, Sep 16, 2004 at 01:03:55PM +0200, Andi Kleen wrote:
> > The scheduler quite rightly expects, for any thread, that any variable
> > which may be stored in a CPU register before the context switch has the
> > same value as after the context switch.
> 
> Just current isn't a varible, it's some inline assembly in a inline
> function.  The question was if that function could be marked const/pure. 

Sigh.  What does that matter?

current_thread, which is what we should be talking about here, is
indeed a function, but its returned value depends wholely on the
stack pointer value.

Since the stack pointer and thread info are invariably coupled
together, it is right to mark it const/pure.

-- 
Russell King
 Linux kernel    2.6 ARM Linux   - http://www.arm.linux.org.uk/
 maintainer of:  2.6 PCMCIA      - http://pcmcia.arm.linux.org.uk/
                 2.6 Serial core

  reply	other threads:[~2004-09-16 14:40 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-09-15 22:50 get_current is __pure__, maybe __const__ even Albert Cahalan
2004-09-15 23:15 ` Jakub Jelinek
2004-09-15 23:29   ` William Lee Irwin III
2004-09-16  2:10     ` Albert Cahalan
2004-09-16  2:36       ` William Lee Irwin III
2004-09-16  2:47         ` Nick Piggin
2004-09-16  3:23           ` William Lee Irwin III
2004-09-16  3:49         ` Albert Cahalan
2004-09-16  3:59           ` William Lee Irwin III
2004-09-16  9:04         ` Russell King
2004-09-16  9:11           ` Andi Kleen
2004-09-16  9:30             ` Russell King
2004-09-16 11:03               ` Andi Kleen
2004-09-16 14:36                 ` Russell King [this message]
2004-09-15 23:27 ` William Lee Irwin III
     [not found] <2ER4z-46B-17@gated-at.bofh.it>
2004-09-16  6:58 ` Andi Kleen
2004-09-16 13:43   ` Albert Cahalan
2004-09-16 14:14   ` Albert Cahalan
2004-09-16 19:27     ` Andi Kleen

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