Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754445Ab3DVRr1 (ORCPT ); Mon, 22 Apr 2013 13:47:27 -0400 Received: from caramon.arm.linux.org.uk ([78.32.30.218]:36575 "EHLO caramon.arm.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754113Ab3DVRr0 (ORCPT ); Mon, 22 Apr 2013 13:47:26 -0400 Date: Mon, 22 Apr 2013 18:47:12 +0100 From: Russell King - ARM Linux To: vinayakm.list@gmail.com Cc: linux-mm@kvack.org, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, rientjes@google.com Subject: Re: [PATCH] mm: add an option to disable bounce Message-ID: <20130422174712.GS14496@n2100.arm.linux.org.uk> References: <1366644180-6140-1-git-send-email-vinayakm.list@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1366644180-6140-1-git-send-email-vinayakm.list@gmail.com> User-Agent: Mutt/1.5.19 (2009-01-05) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1315 Lines: 36 On Mon, Apr 22, 2013 at 08:53:00PM +0530, vinayakm.list@gmail.com wrote: > From: Vinayak Menon > > There are times when HIGHMEM is enabled, but > we don't prefer CONFIG_BOUNCE to be enabled. > CONFIG_BOUNCE can reduce the block device > throughput, and this is not ideal for machines > where we don't gain much by enabling it. So > provide an option to deselect CONFIG_BOUNCE. The > observation was made while measuring eMMC throughput > using iozone on an ARM device with 1GB RAM. > > Signed-off-by: Vinayak Menon > --- > mm/Kconfig | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/mm/Kconfig b/mm/Kconfig > index 3bea74f..29f9736 100644 > --- a/mm/Kconfig > +++ b/mm/Kconfig > @@ -263,8 +263,14 @@ config ZONE_DMA_FLAG > default "1" > > config BOUNCE > + bool "Enable bounce buffers" > def_bool y > depends on BLOCK && MMU && (ZONE_DMA || HIGHMEM) I don't think this is correct. You shouldn't use "bool" with "def_bool". Sure, add the "bool", but also change "def_bool" to "default". -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/