Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754077Ab3DVRiB (ORCPT ); Mon, 22 Apr 2013 13:38:01 -0400 Received: from mail-da0-f41.google.com ([209.85.210.41]:48501 "EHLO mail-da0-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752417Ab3DVRiA (ORCPT ); Mon, 22 Apr 2013 13:38:00 -0400 Message-ID: <5175756C.5080009@gmail.com> Date: Mon, 22 Apr 2013 23:07:48 +0530 From: vinayak User-Agent: Mozilla/5.0 (X11; Linux i686; rv:11.0) Gecko/20120411 Thunderbird/11.0.1 MIME-Version: 1.0 To: Randy Dunlap CC: linux-mm@kvack.org, akpm@linux-foundation.org, rientjes@google.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm: add an option to disable bounce References: <1366644180-6140-1-git-send-email-vinayakm.list@gmail.com> <51756C24.8060505@infradead.org> In-Reply-To: <51756C24.8060505@infradead.org> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1725 Lines: 55 On Monday 22 April 2013 10:28 PM, Randy Dunlap wrote: > On 04/22/13 08:23, 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) >> + help >> + Enable bounce buffers for devices that cannot access >> + the full range of memory available to the CPU. Enabled >> + by default when ZONE_DMA or HIGMEM is selected, but you > > HIGHMEM Thanks. I will correct this. > >> + may say n to override this. >> >> # On the 'tile' arch, USB OHCI needs the bounce pool since tilegx will often >> # have more than 4GB of memory, but we don't currently use the IOTLB to present >> > > -- 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/