From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Scott Parish" Subject: Re: Xen 3.0 Status update Date: Thu, 28 Jul 2005 21:55:39 +0000 Message-ID: <20050728215538.GI4224@us.ibm.com> References: <20050728214320.GH4224@us.ibm.com> <200507282357.28053.mark.williamson@cl.cam.ac.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <200507282357.28053.mark.williamson@cl.cam.ac.uk> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Mark Williamson Cc: Ian Pratt , xen-devel@lists.xensource.com, Scott Parish List-Id: xen-devel@lists.xenproject.org On Thu, Jul 28, 2005 at 11:57:27PM +0100, Mark Williamson wrote: > > I have a patch that introduces zones into xen, and a hypercall to > > request dmaable memory, which i've made xen_contig_memory() use. > > Unfortunately, there still seems to be some places where kmallocs are > > done for dma buffers. (i tried putting all linux memory into ZONE_NORMAL > > and caught a couple of these places) > > The Linux USB stack uses kmalloc-ed memory as DMA buffers as standard > practice. This should still be dealt with correctly by bounce buffer code, > though. I'll have to look at that code. The place i caught was drivers/scsi/sd.c:1471: buffer = kmalloc(512, GFP_KERNEL | __GFP_DMA); I've tried fixing the page allocator to xen_contig_memory() pages that are requested __GFP_DMA, but now get a null pointer dereference i haven't shaken out yet. (i'm not suggesting that xen_contig_memory() is the appropriate long term solution, but for prototyping it should work) sRp -- Scott Parish Signed-off-by: srparish@us.ibm.com