From: Nick Piggin <nickpiggin@yahoo.com.au>
To: William Lee Irwin III <wli@holomorphy.com>
Cc: 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>,
ak@muc.de
Subject: Re: get_current is __pure__, maybe __const__ even
Date: Thu, 16 Sep 2004 12:47:50 +1000 [thread overview]
Message-ID: <4148FED6.100@yahoo.com.au> (raw)
In-Reply-To: <20040916023604.GH9106@holomorphy.com>
William Lee Irwin III wrote:
> On Wed, Sep 15, 2004 at 10:10:20PM -0400, Albert Cahalan wrote:
>
>>I don't think even barrier() is needed.
>>Suppose gcc were to cache the value of
>>current over a schedule. Who cares? It'll
>>be the same after schedule() as it was
>>before.
>
>
> Not over a call to schedule(). In the midst of schedule().
>
In a way, it is. Because after context_switch, the stack
and registers have been replaced by the new task. So if
current was cached somewhere before that task had scheduled
off, then it still would be correct now that it is scheduled
back on.
At points *within* context_switch, current won't be right,
but AFAIKS current is never used in there.
next prev parent reply other threads:[~2004-09-16 2:48 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 [this message]
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
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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