From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jes Sorensen Date: Fri, 17 Mar 2006 14:11:48 +0000 Subject: Re: [patch 2/2] mspec driver Message-Id: <441AC3A4.801@sgi.com> List-Id: References: <20060316163728.06f49c00.akpm@osdl.org> <441ABB68.1020502@yahoo.com.au> <441AC300.8020003@yahoo.com.au> In-Reply-To: <441AC300.8020003@yahoo.com.au> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Nick Piggin Cc: Andrew Morton , torvalds@osdl.org, linux-kernel@vger.kernel.org, linux-ia64@vger.kernel.org, hch@lst.de, cotte@de.ibm.com, Hugh Dickins Nick Piggin wrote: > Jes Sorensen wrote: >> We don't want COW here as the access is backed by special behavior in >> the memory controller. We only allow shared mappings for that reason. >> > No problem, I think you should just stop using the VM_PFNMAP flag then. > [Linus should jump in here if I'm wrong ;)] I'd have to go back and find the discussion to verify, but if I remember correctly the conclusion was that I needed to use it in order to make sure that vm_normal_page() didn't start thinking it was in fact a real page, ie. VM_PFNMAP + never a COW mapping.. Chers, Jes