From: David Howells <dhowells@redhat.com>
To: Andi Kleen <ak@suse.de>
Cc: David Howells <dhowells@redhat.com>,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org#
Subject: Re: [RHEL5 PATCH 1/4] Provide fallback full 64-bit divide/modulus ops for gcc
Date: Tue, 15 Aug 2006 09:29:57 +0100 [thread overview]
Message-ID: <7510.1155630597@warthog.cambridge.redhat.com> (raw)
In-Reply-To: <p734pwea07b.fsf@verdi.suse.de>
Andi Kleen <ak@suse.de> wrote:
> At least Linus' traditional argument against this is that it's better
> to open code these (do_div) so that it's clear to the coder that they
> are really costly.
do_div() is not a full replacement for __udivdi3(), __umoddi3() or
__udivmoddi4(), though I suspect we don't need divisor >= 2^32 anywhere atm.
There are places where the compiler emits these that aren't entirely obvious,
one of which IIRC is in ext2 inode allocation.
David
next prev parent reply other threads:[~2006-08-15 8:30 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-08-14 21:15 [PATCH 0/4] Use 64-bit inode numbers internally in the kernel David Howells
2006-08-14 21:15 ` [RHEL5 PATCH 1/4] Provide fallback full 64-bit divide/modulus ops for gcc David Howells
2006-08-15 6:44 ` Jan Engelhardt
2006-08-15 8:10 ` Andi Kleen
2006-08-15 8:29 ` David Howells [this message]
2006-08-18 8:39 ` Pavel Machek
2006-08-18 10:33 ` David Howells
2006-08-14 21:15 ` [RHEL5 PATCH 2/4] VFS: Make inode numbers 64-bits David Howells
2006-08-15 1:31 ` Al Viro
2006-08-15 8:21 ` David Howells
2006-08-15 9:06 ` Al Viro
2006-08-15 8:32 ` David Howells
2006-08-15 9:02 ` Al Viro
2006-08-15 9:25 ` David Howells
2006-08-15 12:45 ` Stephen Rothwell
2006-08-15 6:48 ` Jan Engelhardt
2006-08-14 21:15 ` [RHEL5 PATCH 3/4] VFS: Clear up u-long-long ino_t print format warnings David Howells
2006-08-14 21:15 ` [RHEL5 PATCH 4/4] VFS: Fix 64-bit ino_t warning in CacheFiles facility David Howells
2006-08-15 0:36 ` [PATCH 0/4] Use 64-bit inode numbers internally in the kernel Josh Boyer
2006-08-15 8:21 ` David Howells
2006-08-15 9:13 ` Al Viro
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