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Groups > linux.kernel > #1418381 > unrolled thread

Re: [PATCH] bitmap_equal memcmp optimization for s390

Started byDavid Howells <dhowells@redhat.com>
First post2016-06-09 16:30 +0200
Last post2016-06-09 16:50 +0200
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  Re: [PATCH] bitmap_equal memcmp optimization for s390 David Howells <dhowells@redhat.com> - 2016-06-09 16:30 +0200
    Re: [PATCH] bitmap_equal memcmp optimization for s390 Martin Schwidefsky <schwidefsky@de.ibm.com> - 2016-06-09 16:50 +0200

#1418381 — Re: [PATCH] bitmap_equal memcmp optimization for s390

FromDavid Howells <dhowells@redhat.com>
Date2016-06-09 16:30 +0200
SubjectRe: [PATCH] bitmap_equal memcmp optimization for s390
Message-ID<rI985-7ym-17@gated-at.bofh.it>
Martin Schwidefsky <schwidefsky@de.ibm.com> wrote:

> I hesitate to put another CONFIG_S390 into common code, alternatively
> __HAVE_ARCH_MEMCMP could be used. There are 7 architectures with the
> define: arc, arm64, blackfin, frv, powerpc, s390 and sparc.
> Of those I guess only powerpc, s390 and sparc will have configs with
> (NR_CPUS > BITS_PER_LONG). For (NR_CPUS <= BITS_PER_LONG) the xor
> optimization is used.

FRV doesn't have __HAVE_ARCH_MEMCMP for __KERNEL__.

David

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#1418400

FromMartin Schwidefsky <schwidefsky@de.ibm.com>
Date2016-06-09 16:50 +0200
Message-ID<rI9rs-7FY-31@gated-at.bofh.it>
In reply to#1418381
On Thu, 09 Jun 2016 15:26:47 +0100
David Howells <dhowells@redhat.com> wrote:

> Martin Schwidefsky <schwidefsky@de.ibm.com> wrote:
> 
> > I hesitate to put another CONFIG_S390 into common code, alternatively
> > __HAVE_ARCH_MEMCMP could be used. There are 7 architectures with the
> > define: arc, arm64, blackfin, frv, powerpc, s390 and sparc.
> > Of those I guess only powerpc, s390 and sparc will have configs with
> > (NR_CPUS > BITS_PER_LONG). For (NR_CPUS <= BITS_PER_LONG) the xor
> > optimization is used.
> 
> FRV doesn't have __HAVE_ARCH_MEMCMP for __KERNEL__.

Yes indeed. How strange to define __HAVE_ARCH_xxx for user space only.

-- 
blue skies,
   Martin.

"Reality continues to ruin my life." - Calvin.

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