From: "H. Peter Anvin" <hpa@zytor.com>
To: Mike Frysinger <vapier.adi@gmail.com>
Cc: Borislav Petkov <petkovbb@googlemail.com>,
Chris Metcalf <cmetcalf@tilera.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
linux-kernel@vger.kernel.org,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Thomas Gleixner <tglx@linutronix.de>,
Andrew Morton <akpm@linux-foundation.org>,
Ingo Molnar <mingo@elte.hu>
Subject: Re: [GIT PULL] core/hweight changes for v2.6.35
Date: Fri, 13 Aug 2010 14:56:32 -0700 [thread overview]
Message-ID: <4C65BF90.6000302@zytor.com> (raw)
In-Reply-To: <AANLkTikvJna6vnc73RVhVAJZ8mERJoFk=V6Nwq-3HHWz@mail.gmail.com>
On 08/13/2010 02:42 PM, Mike Frysinger wrote:
> On Mon, May 17, 2010 at 17:21, Ingo Molnar wrote:
>> arch/alpha/include/asm/bitops.h | 18 +++++----
>> arch/ia64/include/asm/bitops.h | 11 +++--
>> arch/sparc/include/asm/bitops_64.h | 11 +++--
>> arch/x86/include/asm/bitops.h | 4 +-
>> include/asm-generic/bitops/arch_hweight.h | 25 ++++++++++++
>> include/asm-generic/bitops/const_hweight.h | 42 ++++++++++++++++++++
>> include/asm-generic/bitops/hweight.h | 8 +---
>
> did this miss Blackfin because the original patch was against the
> 2.6.34 tree ? just wondering why it now build fails ...
>
> doing a simple grep shows that the new "tile" arch may also be broken
> as it uses "hweight32" ...
>
> considering __sw_hweightX only exist when the generic hweight is in
> play, wouldnt it make sense to have
> include/asm-generic/bitops/arch_hweight.h not always define things ?
> then most arches can simply pull in
> include/asm-generic/bitops/hweight.h without having to worry about the
> random inner details of hweight cruft.
>
__sw_hweightX can exist even when generic hweight isn't in use per se,
because the arch implementation can wrapper the software implementation.
This is the case on x86, for example -- most x86 CPUs don't have popcnt
yet, so on those the x86 implementation end up calling the
__sw_hweight*() implementations.
-hpa
next prev parent reply other threads:[~2010-08-13 21:57 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-17 21:21 Ingo Molnar
2010-05-17 21:46 ` Linus Torvalds
2010-05-17 22:06 ` H. Peter Anvin
2010-05-17 22:57 ` [tip:core/hweight] x86, hweight: Use a 32-bit popcnt for __arch_hweight32() tip-bot for H. Peter Anvin
2010-05-17 23:04 ` [GIT PULL] UPDATED - core/hweight changes for v2.6.35 H. Peter Anvin
2010-08-13 21:42 ` [GIT PULL] " Mike Frysinger
2010-08-13 21:56 ` H. Peter Anvin [this message]
2010-08-13 21:59 ` Mike Frysinger
2010-08-14 0:11 ` H. Peter Anvin
2010-08-14 13:44 ` Borislav Petkov
2010-08-14 0:32 ` [PATCH] arch/tile: Rename the hweight() implementations to __arch_hweight() Chris Metcalf
2010-08-14 1:02 ` Mike Frysinger
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