From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Sun, 25 Mar 2007 16:00:50 -0800 From: Andrew Morton Subject: Re: [patch 2/3] only allow nonlinear vmas for ram backed filesystems Message-Id: <20070325160050.fe7cb284.akpm@linux-foundation.org> In-Reply-To: References: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Miklos Szeredi Cc: a.p.zijlstra@chello.nl, linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: On Sat, 24 Mar 2007 23:09:19 +0100 Miklos Szeredi wrote: > Dirty page accounting/limiting doesn't work for nonlinear mappings, Doesn't it? iirc the problem is that we don't correctly re-clean the ptes while starting writeout. And the dirty-page accounting is in fact correct (it'd darn well better be). > so > for non-ram backed filesystems emulate with linear mappings. This > retains ABI compatibility with previous kernels at minimal code cost. > > All known users of nonlinear mappings actually use tmpfs, so this > shouldn't have any negative effect. Unless someone is using remap_file_pages() against an ext3 file, in which case their application stops working? That would be a problem. These guys: http://www.technovelty.org/code/linux/fremap.html, for example, will be in for a little surprise. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org