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Date: Fri, 20 Sep 2002 11:40:16 +0200 (CEST)
From: Ingo Molnar <mingo@elte.hu>
Reply-To: Ingo Molnar <mingo@elte.hu>
To: Oleg Drokin <green@namesys.com>
Cc: Linus Torvalds <torvalds@transmeta.com>,
       William Lee Irwin III <wli@holomorphy.com>,
       <linux-kernel@vger.kernel.org>
Subject: Re: [patch] generic-pidhash-2.5.36-D4, BK-curr
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On Fri, 20 Sep 2002, Oleg Drokin wrote:

> > +			if (cmpxchg(&map->page, NULL, page))
> > +				free_page(page);
> 
> Note that this piece breaks compilation for every arch that does not
> have cmpxchg implementation.
> This is the case with x86 (with CONFIG_X86_CMPXCHG undefined, e.g. i386),
> ARM, CRIS, m68k, MIPS, MIPS64, PARISC, s390, SH, sparc32, UML (for x86).

we need a cmpxchg() function in the generic library, using a spinlock.  
Then every architecture can enhance the implementation if it wishes to.

	Ingo

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