Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933863AbcJZTwO (ORCPT ); Wed, 26 Oct 2016 15:52:14 -0400 Received: from mail-wm0-f42.google.com ([74.125.82.42]:35404 "EHLO mail-wm0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754351AbcJZTwK (ORCPT ); Wed, 26 Oct 2016 15:52:10 -0400 Message-ID: <58110959.90901@plexistor.com> Date: Wed, 26 Oct 2016 22:51:53 +0300 From: Boaz Harrosh User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: Brian Boylston , linux-nvdimm@ml01.01.org CC: oliver.moreno@hpe.com, x86@kernel.org, linux-kernel@vger.kernel.org, Ingo Molnar , Al Viro , "H. Peter Anvin" , Thomas Gleixner Subject: Re: [PATCH v2 1/3] introduce memcpy_nocache() References: <20161026155021.20892-1-brian.boylston@hpe.com> <20161026155021.20892-2-brian.boylston@hpe.com> In-Reply-To: <20161026155021.20892-2-brian.boylston@hpe.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3718 Lines: 110 On 10/26/2016 06:50 PM, Brian Boylston wrote: > Introduce memcpy_nocache() as a memcpy() that avoids the processor cache > if possible. Without arch-specific support, this defaults to just > memcpy(). For now, include arch-specific support for x86. > > Cc: Ross Zwisler > Cc: Thomas Gleixner > Cc: Ingo Molnar > Cc: "H. Peter Anvin" > Cc: > Cc: Al Viro > Cc: Dan Williams > Signed-off-by: Brian Boylston > Reviewed-by: Toshi Kani > Reported-by: Oliver Moreno > --- > arch/x86/include/asm/string_32.h | 3 +++ > arch/x86/include/asm/string_64.h | 3 +++ > arch/x86/lib/misc.c | 12 ++++++++++++ > include/linux/string.h | 15 +++++++++++++++ > 4 files changed, 33 insertions(+) > > diff --git a/arch/x86/include/asm/string_32.h b/arch/x86/include/asm/string_32.h > index 3d3e835..64f80c0 100644 > --- a/arch/x86/include/asm/string_32.h > +++ b/arch/x86/include/asm/string_32.h > @@ -196,6 +196,9 @@ static inline void *__memcpy3d(void *to, const void *from, size_t len) > > #endif > > +#define __HAVE_ARCH_MEMCPY_NOCACHE > +extern void *memcpy_nocache(void *dest, const void *src, size_t count); > + > #define __HAVE_ARCH_MEMMOVE > void *memmove(void *dest, const void *src, size_t n); > > diff --git a/arch/x86/include/asm/string_64.h b/arch/x86/include/asm/string_64.h > index 90dbbd9..a8fdd55 100644 > --- a/arch/x86/include/asm/string_64.h > +++ b/arch/x86/include/asm/string_64.h > @@ -51,6 +51,9 @@ extern void *__memcpy(void *to, const void *from, size_t len); > #define memcpy(dst, src, len) __inline_memcpy((dst), (src), (len)) > #endif > > +#define __HAVE_ARCH_MEMCPY_NOCACHE > +extern void *memcpy_nocache(void *dest, const void *src, size_t count); > + > #define __HAVE_ARCH_MEMSET > void *memset(void *s, int c, size_t n); > void *__memset(void *s, int c, size_t n); > diff --git a/arch/x86/lib/misc.c b/arch/x86/lib/misc.c > index 76b373a..c993ab3 100644 > --- a/arch/x86/lib/misc.c > +++ b/arch/x86/lib/misc.c > @@ -1,3 +1,6 @@ > +#include > +#include > + > /* > * Count the digits of @val including a possible sign. > * > @@ -19,3 +22,12 @@ int num_digits(int val) > } > return d; > } > + > +#ifdef __HAVE_ARCH_MEMCPY_NOCACHE > +void *memcpy_nocache(void *dest, const void *src, size_t count) > +{ > + __copy_from_user_inatomic_nocache(dest, src, count); > + return dest; > +} > +EXPORT_SYMBOL(memcpy_nocache); > +#endif > diff --git a/include/linux/string.h b/include/linux/string.h > index 26b6f6a..7f40c41 100644 > --- a/include/linux/string.h > +++ b/include/linux/string.h > @@ -102,6 +102,21 @@ extern void * memset(void *,int,__kernel_size_t); > #ifndef __HAVE_ARCH_MEMCPY > extern void * memcpy(void *,const void *,__kernel_size_t); > #endif > + > +#ifndef __HAVE_ARCH_MEMCPY_NOCACHE > +/** > + * memcpy_nocache - Copy one area of memory to another, avoiding the > + * processor cache if possible > + * @dest: Where to copy to > + * @src: Where to copy from > + * @count: The size of the area. > + */ > +static inline void *memcpy_nocache(void *dest, const void *src, size_t count) > +{ > + return memcpy(dest, src, count); > +} What about memcpy_to_pmem() in linux/pmem.h it already has all the arch switches. Feels bad to add yet just another arch switch over __copy_user_nocache Just feels like too many things that do the same thing. Sigh Boaz > +#endif > + > #ifndef __HAVE_ARCH_MEMMOVE > extern void * memmove(void *,const void *,__kernel_size_t); > #endif >