Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756629Ab1EPXNb (ORCPT ); Mon, 16 May 2011 19:13:31 -0400 Received: from hera.kernel.org ([140.211.167.34]:36692 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755766Ab1EPXN3 (ORCPT ); Mon, 16 May 2011 19:13:29 -0400 Date: Mon, 16 May 2011 23:13:07 GMT From: tip-bot for David Rientjes Message-ID: Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@redhat.com, tglx@linutronix.de, hpa@linux.intel.com, rientjes@google.com Reply-To: mingo@redhat.com, hpa@zytor.com, linux-kernel@vger.kernel.org, tglx@linutronix.de, rientjes@google.com, hpa@linux.intel.com In-Reply-To: References: To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/mm] x86, mm: Allow ZONE_DMA to be configurable Git-Commit-ID: dc382fd5bcca7098a984705ed6ac880f539d068e X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.3 (hera.kernel.org [127.0.0.1]); Mon, 16 May 2011 23:13:12 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2939 Lines: 83 Commit-ID: dc382fd5bcca7098a984705ed6ac880f539d068e Gitweb: http://git.kernel.org/tip/dc382fd5bcca7098a984705ed6ac880f539d068e Author: David Rientjes AuthorDate: Mon, 16 May 2011 13:54:10 -0700 Committer: H. Peter Anvin CommitDate: Mon, 16 May 2011 14:03:28 -0700 x86, mm: Allow ZONE_DMA to be configurable ZONE_DMA is unnecessary for a large number of machines that do not require less than 32-bit DMA addressing, e.g. ISA legacy DMA or PCI cards with a restricted DMA address mask. This patch allows users to disable ZONE_DMA for x86 if they know they will not be using such devices with their kernel. This prevents the VM from unnecessarily reserving a ratio of memory (defaulting to 1/256th of system capacity) with lowmem_reserve_ratio for such allocations when it will never be used. Signed-off-by: David Rientjes Link: http://lkml.kernel.org/r/alpine.DEB.2.00.1105161353560.4353@chino.kir.corp.google.com Signed-off-by: H. Peter Anvin --- arch/x86/Kconfig | 9 ++++++++- arch/x86/mm/init_32.c | 2 ++ arch/x86/mm/init_64.c | 2 ++ 3 files changed, 12 insertions(+), 1 deletions(-) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 648fca4..0eb801a 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -112,7 +112,14 @@ config MMU def_bool y config ZONE_DMA - def_bool y + bool "DMA memory allocation support" if EXPERT + default y + help + DMA memory allocation support allows devices with less than 32-bit + addressing to allocate within the first 16MB of address space. + Disable if no such devices will be used. + + If unsure, say Y. config SBUS bool diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c index 2cde0a34..29f7c6d 100644 --- a/arch/x86/mm/init_32.c +++ b/arch/x86/mm/init_32.c @@ -678,8 +678,10 @@ static void __init zone_sizes_init(void) { unsigned long max_zone_pfns[MAX_NR_ZONES]; memset(max_zone_pfns, 0, sizeof(max_zone_pfns)); +#ifdef CONFIG_ZONE_DMA max_zone_pfns[ZONE_DMA] = virt_to_phys((char *)MAX_DMA_ADDRESS) >> PAGE_SHIFT; +#endif max_zone_pfns[ZONE_NORMAL] = max_low_pfn; #ifdef CONFIG_HIGHMEM max_zone_pfns[ZONE_HIGHMEM] = highend_pfn; diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index 0404bb3..d865c4a 100644 --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -616,7 +616,9 @@ void __init paging_init(void) unsigned long max_zone_pfns[MAX_NR_ZONES]; memset(max_zone_pfns, 0, sizeof(max_zone_pfns)); +#ifdef CONFIG_ZONE_DMA max_zone_pfns[ZONE_DMA] = MAX_DMA_PFN; +#endif max_zone_pfns[ZONE_DMA32] = MAX_DMA32_PFN; max_zone_pfns[ZONE_NORMAL] = max_pfn; -- 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/