From mboxrd@z Thu Jan 1 00:00:00 1970 Received: by nz-out-0506.google.com with SMTP id s1so1265969nze for ; Mon, 29 Oct 2007 10:51:48 -0700 (PDT) Message-ID: <45a44e480710291051s7ffbb582x64ea9524c197b48a@mail.gmail.com> Date: Mon, 29 Oct 2007 13:51:46 -0400 From: "Jaya Kumar" Subject: Re: vm_ops.page_mkwrite() fails with vmalloc on 2.6.23 In-Reply-To: <1193677302.27652.56.camel@twins> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <1193064057.16541.1.camel@matrix> <20071029004002.60c7182a.akpm@linux-foundation.org> <45a44e480710290117u492dbe82ra6344baf8bb1e370@mail.gmail.com> <1193677302.27652.56.camel@twins> Sender: owner-linux-mm@kvack.org Return-Path: To: Peter Zijlstra Cc: Andrew Morton , stefani@seibold.net, linux-kernel@vger.kernel.org, David Howells , linux-mm@kvack.org List-ID: On 10/29/07, Peter Zijlstra wrote: > On Mon, 2007-10-29 at 01:17 -0700, Jaya Kumar wrote: > > 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. > I thought I had it working. I saw the display update after each mmap/write sequence to the framebuffer. I need to check if there's an munmap or anything else going on in between write sequences that would cause it to behave like page_mkclean was working. Is it correct to assume that page_mkclean should mark the pages read-only so that the next write would again trigger mkwrite? Even if the page was from a vmalloc_to_page()? Thanks, jaya -- 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