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Message-ID: <467F6C8F.9040400@yahoo.com.au>
Date: Mon, 25 Jun 2007 17:19:43 +1000
From: Nick Piggin <nickpiggin@yahoo.com.au>
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To: Andi Kleen <andi@firstfloor.org>
CC: Nick Piggin <npiggin@suse.de>,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
       Linux Memory Management List <linux-mm@kvack.org>,
       linux-fsdevel@vger.kernel.org
Subject: Re: [patch 1/3] add the fsblock layer
References: <20070624014528.GA17609@wotan.suse.de>	<20070624014613.GB17609@wotan.suse.de> <p73fy4h5q3c.fsf@bingen.suse.de>
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Andi Kleen wrote:
> Nick Piggin <npiggin@suse.de> writes:
> 
> 
> [haven't read everything, just commenting on something that caught my eye]
> 
> 
>>+struct fsblock {
>>+	atomic_t	count;
>>+	union {
>>+		struct {
>>+			unsigned long	flags; /* XXX: flags could be int for better packing */
> 
> 
> int is not supported by many architectures, but works on x86 at least.

Yeah, that would be nice. We could actually use this for buffer_head as well,
but saving 4% there isn't so important as saving 20% for fsblock :)


> Hmm, could define a macro DECLARE_ATOMIC_BITMAP(maxbit) that expands to the smallest
> possible type for each architecture. And a couple of ugly casts for set_bit et.al.
> but those could be also hidden in macros. Should be relatively easy to do.

Cool. It would probably be useful for other things as well.

-- 
SUSE Labs, Novell Inc.
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