From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: Re: vm_ops.page_mkwrite() fails with vmalloc on 2.6.23 From: Peter Zijlstra In-Reply-To: <45a44e480710290117u492dbe82ra6344baf8bb1e370@mail.gmail.com> References: <1193064057.16541.1.camel@matrix> <20071029004002.60c7182a.akpm@linux-foundation.org> <45a44e480710290117u492dbe82ra6344baf8bb1e370@mail.gmail.com> Content-Type: text/plain Date: Mon, 29 Oct 2007 18:01:42 +0100 Message-Id: <1193677302.27652.56.camel@twins> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Jaya Kumar Cc: Andrew Morton , stefani@seibold.net, linux-kernel@vger.kernel.org, David Howells , linux-mm@kvack.org List-ID: On Mon, 2007-10-29 at 01:17 -0700, Jaya Kumar wrote: > On 10/29/07, Andrew Morton wrote: > > On Mon, 22 Oct 2007 16:40:57 +0200 Stefani Seibold wrote: > > > > > > The problem original occurs with the fb_defio driver (driver/video/fb_defio.c). > > > This driver use the vm_ops.page_mkwrite() handler for tracking the modified pages, > > > which will be in an extra thread handled, to perform the IO and clean and > > > write protect all pages with page_clean(). > > > > An aside, I just tested that deferred IO works fine on 2.6.22.10/pxa255. > > I understood from the thread that PeterZ is looking into page_mkclean > changes which I guess went into 2.6.23. I'm also happy to help in any > way if the way we're doing fb_defio needs to change. OK, seems I can't read. Or at least, I missed a large part of the problem. page_mkclean() hasn't changed, it was ->page_mkwrite() that changed. And looking at the fb_defio code, I'm not sure I understand how its page_mkclean() use could ever have worked. The proposed patch [1] only fixes the issue of ->page_mkwrite() on vmalloc()'ed memory. Not page_mkclean(), and that has never worked from what I can make of it. Jaya, could you shed some light on this? I presume you had your display working. [1] which I will clean up and resend after this issue is cleared up - and preferably tested by someone who has this hardware. -- 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