Re: 2.5 'what to expect'

From: Brian Gerst <bgerst@didntduck.org>
To: Steven Cole <elenstev@mesatop.com>
Cc: Larry McVoy <lm@bitmover.com>,
	Alan Cox <alan@lxorguk.ukuu.org.uk>,
	Tomas Szepe <szepe@pinerecords.com>,
	Dave Jones <davej@codemonkey.org.uk>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: 2.5 'what to expect'
Date: Fri, 11 Jul 2003 13:51:53 -0400	[thread overview]
Message-ID: <3F0EF939.90506@didntduck.org> (raw)
In-Reply-To: <1057937849.2337.4.camel@spc9.esa.lanl.gov>

Steven Cole wrote:
> On Fri, 2003-07-11 at 09:11, Larry McVoy wrote:
> 
>>On Fri, Jul 11, 2003 at 04:00:33PM +0100, Alan Cox wrote:
>>
>>>On Gwe, 2003-07-11 at 15:46, Tomas Szepe wrote:
>>>
>>>>>>- gcc 3.2.2-5 as shipped by Red Hat generates incorrect code in the
>>>>>>  kmalloc optimisation introduced in 2.5.71
>>>>>>  See http://linus.bkbits.net:8080/linux-2.5/cset@1.1410
>>>>>
>>>>>This URL appears wrong!
>>>>
>>>>Nahh, that's just the same old annoying bkbits bug.  Try with lynx...
>>>
>>>I did - it references a changeset unrelayed to kmalloc
>>
>>I know, sorry.  The version numbers in BK are not stable, they can't be.
>>You have to use the underlying internal version number.  If someone who
>>knows can show me the output of 
>>
>>	bk changes -r<correct rev>
>>
>>for that changeset I will figure out a way to have a URL that doesn't change
>>and send it to Dave for that doc as well as post it there.
> 
> 
> This looks like the right one as currently numbered.
> 
> http://linus.bkbits.net:8080/linux-2.5/cset@1.1215.127.10
> 
> Steven

There is no problem with the current version of this patch.  I rewrote 
the original patch to work around the bug in gcc.  The bug is that:

	if (size < X) return kmem_cache_alloc(...);

would not cause the remaining if statements to be marked as dead code, but:

	if (size < X) goto found;
	...
	found: return kmem_cache_alloc(...);

does optimize properly.

--
				Brian Gerst