Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756955AbYCHGfq (ORCPT ); Sat, 8 Mar 2008 01:35:46 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752529AbYCHGfh (ORCPT ); Sat, 8 Mar 2008 01:35:37 -0500 Received: from rv-out-0910.google.com ([209.85.198.184]:26864 "EHLO rv-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752406AbYCHGfg (ORCPT ); Sat, 8 Mar 2008 01:35:36 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=bDVE1F8UMMpvNx/pMcj+4inY1lmgbtjy7thaYPWuMEpkoiqmXvcY2Y6Z0gUPmOTiez7spuoJUnrQsv+iX7sH8qTP8FDvIK0bXG/q77xmWFsZ6uW57PKqgnnEbuS0YHbFcoblaXYLpA9q1/0eyif+kVBqhfr78u4SRRoazLpyanw= Message-ID: <86802c440803072235r3ca6013cufae3ed62cd67e60f@mail.gmail.com> Date: Fri, 7 Mar 2008 22:35:35 -0800 From: "Yinghai Lu" To: "Christoph Lameter" Subject: Re: [PATCH] [8/13] Enable the mask allocator for x86 Cc: "Andi Kleen" , linux-kernel@vger.kernel.org, linux-mm@kvack.org In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <200803071007.493903088@firstfloor.org> <20080307090718.A609E1B419C@basil.firstfloor.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1448 Lines: 32 On Fri, Mar 7, 2008 at 6:37 PM, Christoph Lameter wrote: > On Fri, 7 Mar 2008, Andi Kleen wrote: > > > - Disable old ZONE_DMA > > No fixed size ZONE_DMA now anymore. All existing users of __GFP_DMA rely > > on the compat call to the maskable allocator in alloc/free_pages > > - Call maskable allocator initialization functions at boot > > - Add TRAD_DMA_MASK for the compat functions > > - Remove dma_reserve call > > This looks okay for the disabling part. But note that there are various > uses of MAX_DMA_ADDRESS (sparsemem, bootmem allocator) that are currently > suboptimal because they set a boundary at 16MB for allocation of > potentially large operating system structures. That boundary continues to > exist despite the removal of ZONE_DMA? > > It would be better to remove ZONE_DMA32 instead and enlarge ZONE_DMA so > that it can take over the role of ZONE_DMA. Set the boundary for > MAX_DMA_ADDRESS to the boundary for ZONE_DMA32. Then the > allocations for sparse and bootmem will be allocated above 4GB which > leaves lots of the lower space available for 32 bit DMA capable devices. good. i like the idea... How about system with only 4G or less? YH -- 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/