From: Dave Jones <davej@redhat.com>
To: Jan Engelhardt <jengelh@linux01.gwdg.de>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] no need to check for NULL before calling kfree() -fs/ext2/
Date: Sun, 27 Mar 2005 12:40:26 -0500 [thread overview]
Message-ID: <20050327174026.GA708@redhat.com> (raw)
In-Reply-To: <Pine.LNX.4.61.0503271708350.20909@yvahk01.tjqt.qr>
On Sun, Mar 27, 2005 at 05:12:58PM +0200, Jan Engelhardt wrote:
> Well, kfree inlined was already mentioned but forgotten again.
> What if this was used:
>
> inline static void kfree_WRAP(void *addr) {
> if(likely(addr != NULL)) {
> kfree_real(addr);
> }
> return;
> }
>
> And remove the NULL-test in kfree_real()? Then we would have:
Am I the only person who is completely fascinated by the
effort being spent here micro-optimising something thats
almost never in a path that needs optimising ?
I'd be amazed if any of this masturbation showed the tiniest
blip on a real workload, or even on a benchmark other than
one crafted specifically to test kfree in a loop.
That each occurance of this 'optimisation' also saves a handful
of bytes in generated code is it's only real benefit afaics.
Even then, if a functions cache performance is better off because
we trimmed a few bytes from the tail of a function, I'd be
completely amazed.
I guess April 1st came early this year.
Dave
next prev parent reply other threads:[~2005-03-27 17:40 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-03-25 22:08 [PATCH] no need to check for NULL before calling kfree() - fs/ext2/ Jesper Juhl
2005-03-25 22:29 ` linux-os
2005-03-25 22:44 ` Jesper Juhl
2005-03-26 7:50 ` Pekka Enberg
2005-03-26 8:32 ` Arjan van de Ven
2005-03-26 23:21 ` [PATCH] no need to check for NULL before calling kfree() -fs/ext2/ linux-os
2005-03-26 23:34 ` Marcin Dalecki
2005-03-27 2:00 ` Horst von Brand
2005-03-27 3:18 ` Marcin Dalecki
2005-03-27 22:12 ` linux-os
2005-03-26 23:54 ` Jesper Juhl
2005-03-27 0:05 ` Lee Revell
2005-03-27 10:55 ` Jesper Juhl
2005-03-27 14:56 ` Paul Jackson
2005-03-27 15:12 ` Jan Engelhardt
2005-03-27 17:40 ` Dave Jones [this message]
2005-03-27 18:17 ` Jan Engelhardt
2005-03-27 19:25 ` Pekka Enberg
2005-03-27 22:56 ` Jesper Juhl
2005-03-28 4:53 ` Paul Jackson
2005-03-30 18:57 ` Jesper Juhl
2005-03-28 1:20 ` Horst von Brand
2005-03-28 4:10 ` Paul Jackson
2005-03-28 12:58 ` Geert Uytterhoeven
2005-03-29 2:52 ` Lee Revell
2005-03-29 6:30 ` Pekka Enberg
2005-03-29 7:06 ` Jan Engelhardt
2005-03-29 7:24 ` Pekka J Enberg
2005-03-30 2:44 ` Paul Jackson
2005-03-30 6:13 ` Pekka J Enberg
2005-03-30 6:16 ` Paul Jackson
2005-03-30 7:15 ` P Lavin
2005-03-30 14:20 ` Jesper Juhl
2005-03-30 19:10 ` Jesper Juhl
2005-04-09 2:21 ` Jesper Juhl
2005-03-28 4:07 ` [PATCH] " Paul Jackson
2005-03-27 8:45 ` Arjan van de Ven
2005-03-27 12:51 ` Denis Vlasenko
2005-03-27 14:28 ` Arjan van de Ven
2005-03-27 23:13 ` [PATCH] no need to check for NULL before calling kfree()-fs/ext2/ linux-os
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