From: "Alexander van Heukelum" <heukelum@fastmail.fm>
To: "Linus Torvalds" <torvalds@linux-foundation.org>,
"Harvey Harrison" <harvey.harrison@gmail.com>,
"David S. Miller" <davem@davemloft.net>
Cc: "Ingo Molnar" <mingo@elte.hu>,
"Andrew Morton" <akpm@linux-foundation.org>,
"LKML" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] bitops: simplify generic bit finding functions
Date: Mon, 28 Apr 2008 16:58:43 +0200 [thread overview]
Message-ID: <1209394723.22937.1250267923@webmail.messagingengine.com> (raw)
In-Reply-To: <alpine.LFD.1.10.0804271325350.3119@woody.linux-foundation.org>
On Sun, 27 Apr 2008 13:26:34 -0700 (PDT), "Linus Torvalds"
<torvalds@linux-foundation.org> said:
> On Sun, 27 Apr 2008, Harvey Harrison wrote:
> >
> > No need for a sentinal if we explicitly catch the no bits/all bits set
> > cases, make it clear they are special cases returning size/BITS_PER_LONG.
>
> These things need to be re-done anyway. David already complained that the
> thing inlines to something much much too big.
>
> Let's just make it not be an inline at all.
Hello,
I think that's the wrong way to go about it. The problem that David
Miller pointed out was that the small-bitmap optimization caused an
inliningdisaster. Apparently, the generic version of __ffs is very
big on sparc64. In my opinion the implementation of __ffs should be
made out of line. If you move the wrapper of find_first_bit etc
out of line, all possibilities of optimization will be destroyed.
Better to remove them completely, then.
Greetings,
Alexander
> Linus
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Alexander van Heukelum
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next prev parent reply other threads:[~2008-04-28 14:58 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-04-27 20:19 [PATCH] bitops: simplify generic bit finding functions Harvey Harrison
2008-04-27 20:26 ` Linus Torvalds
2008-04-27 20:29 ` Harvey Harrison
2008-04-27 20:36 ` Al Viro
2008-04-27 20:38 ` Harvey Harrison
2008-04-27 20:38 ` Linus Torvalds
2008-04-27 21:02 ` Al Viro
2008-04-28 14:04 ` Thomas Gleixner
2008-04-28 15:10 ` Alexander van Heukelum
2008-04-28 15:58 ` Thomas Gleixner
2008-04-28 16:25 ` Linus Torvalds
2008-04-28 16:47 ` Thomas Gleixner
2008-04-28 16:54 ` Linus Torvalds
2008-04-28 19:26 ` Thomas Gleixner
2008-04-28 19:37 ` Linus Torvalds
2008-04-28 21:55 ` Ingo Molnar
2008-04-29 10:01 ` [PATCH] bitops: remove "optimizations" Thomas Gleixner
2008-04-29 10:03 ` David Miller
2008-04-29 12:34 ` David Miller
2008-04-29 14:20 ` Ingo Molnar
2008-04-29 22:31 ` David Miller
2008-04-29 16:51 ` Thomas Gleixner
2008-04-29 22:58 ` David Miller
2008-04-29 23:30 ` David Miller
2008-04-28 19:57 ` [PATCH] bitops: simplify generic bit finding functions Andi Kleen
2008-04-28 14:58 ` Alexander van Heukelum [this message]
2008-04-28 14:32 ` Alexander van Heukelum
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