From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <scottwood@freescale.com>
Received: from na01-bl2-obe.outbound.protection.outlook.com
 (mail-bl2on0119.outbound.protection.outlook.com [65.55.169.119])
 (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits))
 (No client certificate requested)
 by lists.ozlabs.org (Postfix) with ESMTPS id BB2081A04ED
 for <linuxppc-dev@lists.ozlabs.org>; Tue, 29 Sep 2015 10:29:48 +1000 (AEST)
Date: Mon, 28 Sep 2015 19:29:35 -0500
From: Scott Wood <scottwood@freescale.com>
To: Christophe Leroy <christophe.leroy@c-s.fr>
CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>, Paul Mackerras
 <paulus@samba.org>, Michael Ellerman <mpe@ellerman.id.au>,
 <linux-kernel@vger.kernel.org>, <linuxppc-dev@lists.ozlabs.org>
Subject: Re: [PATCH v2 22/25] powerpc32: move xxxxx_dcache_range() functions
 inline
Message-ID: <20150929002935.GK6161@home.buserror.net>
References: <cover.1442939410.git.christophe.leroy@c-s.fr>
 <c1c88096cb3f6ee71048dbab44ffb9ac260b07a3.1442939410.git.christophe.leroy@c-s.fr>
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
In-Reply-To: <c1c88096cb3f6ee71048dbab44ffb9ac260b07a3.1442939410.git.christophe.leroy@c-s.fr>
List-Id: Linux on PowerPC Developers Mail List <linuxppc-dev.lists.ozlabs.org>
List-Unsubscribe: <https://lists.ozlabs.org/options/linuxppc-dev>,
 <mailto:linuxppc-dev-request@lists.ozlabs.org?subject=unsubscribe>
List-Archive: <http://lists.ozlabs.org/pipermail/linuxppc-dev/>
List-Post: <mailto:linuxppc-dev@lists.ozlabs.org>
List-Help: <mailto:linuxppc-dev-request@lists.ozlabs.org?subject=help>
List-Subscribe: <https://lists.ozlabs.org/listinfo/linuxppc-dev>,
 <mailto:linuxppc-dev-request@lists.ozlabs.org?subject=subscribe>

On Tue, Sep 22, 2015 at 06:51:13PM +0200, Christophe Leroy wrote:
> flush/clean/invalidate _dcache_range() functions are all very
> similar and are quite short. They are mainly used in __dma_sync()
> perf_event locate them in the top 3 consumming functions during
> heavy ethernet activity
> 
> They are good candidate for inlining, as __dma_sync() does
> almost nothing but calling them
> 
> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
> ---
> New in v2
> 
>  arch/powerpc/include/asm/cacheflush.h | 55 +++++++++++++++++++++++++++--
>  arch/powerpc/kernel/misc_32.S         | 65 -----------------------------------
>  arch/powerpc/kernel/ppc_ksyms.c       |  2 ++
>  3 files changed, 54 insertions(+), 68 deletions(-)
> 
> diff --git a/arch/powerpc/include/asm/cacheflush.h b/arch/powerpc/include/asm/cacheflush.h
> index 6229e6b..6169604 100644
> --- a/arch/powerpc/include/asm/cacheflush.h
> +++ b/arch/powerpc/include/asm/cacheflush.h
> @@ -47,12 +47,61 @@ static inline void __flush_dcache_icache_phys(unsigned long physaddr)
>  }
>  #endif
>  
> -extern void flush_dcache_range(unsigned long start, unsigned long stop);
>  #ifdef CONFIG_PPC32
> -extern void clean_dcache_range(unsigned long start, unsigned long stop);
> -extern void invalidate_dcache_range(unsigned long start, unsigned long stop);
> +/*
> + * Write any modified data cache blocks out to memory and invalidate them.
> + * Does not invalidate the corresponding instruction cache blocks.
> + */
> +static inline void flush_dcache_range(unsigned long start, unsigned long stop)
> +{
> +	void *addr = (void *)(start & ~(L1_CACHE_BYTES - 1));
> +	unsigned int size = stop - (unsigned long)addr + (L1_CACHE_BYTES - 1);
> +	unsigned int i;
> +
> +	for (i = 0; i < size >> L1_CACHE_SHIFT; i++, addr += L1_CACHE_BYTES)
> +		dcbf(addr);
> +	if (i)
> +		mb();	/* sync */
> +}

I know this is 32-bit-specific code, but it's still bad practice to use
"unsigned int" for addresses or sizes thereof.

-Scott