From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail138.messagelabs.com (mail138.messagelabs.com [216.82.249.35]) by kanga.kvack.org (Postfix) with SMTP id DD7D46B006A for ; Fri, 26 Jun 2009 03:48:37 -0400 (EDT) Received: by yxe38 with SMTP id 38so911089yxe.12 for ; Fri, 26 Jun 2009 00:50:09 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20090625111233.f6f26050.akpm@linux-foundation.org> References: <20090624105413.13925.65192.sendpatchset@rx1.opensource.se> <20090624195647.9d0064c7.akpm@linux-foundation.org> <20090625000359.7e201c58.akpm@linux-foundation.org> <20090625173806.GB25320@linux-sh.org> <20090625111233.f6f26050.akpm@linux-foundation.org> Date: Fri, 26 Jun 2009 16:50:09 +0900 Message-ID: Subject: Re: [PATCH] video: arch specific page protection support for deferred io From: Magnus Damm Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Sender: owner-linux-mm@kvack.org To: Andrew Morton Cc: Paul Mundt , linux-fbdev-devel@lists.sourceforge.net, adaplas@gmail.com, arnd@arndb.de, linux-mm@kvack.org, jayakumar.lkml@gmail.com List-ID: On Fri, Jun 26, 2009 at 3:12 AM, Andrew Morton w= rote: > On Fri, 26 Jun 2009 02:38:06 +0900 > Paul Mundt wrote: > >> On Thu, Jun 25, 2009 at 12:03:59AM -0700, Andrew Morton wrote: >> > On Thu, 25 Jun 2009 15:06:24 +0900 Magnus Damm = wrote: >> > > There are 3 levels of dependencies: >> > > 1: pgprot_noncached() patches from Arnd >> > > 2: mm: uncached vma support with writenotify >> > > 3: video: arch specfic page protection support for deferred io >> > > >> > > 2 depends on 1 to compile, but 3 (this one) is disconnected from 2 a= nd >> > > 1. So this patch can be merged independently. >> > >> > OIC. =A0I didn't like the idea of improper runtime operation ;) >> > >> > Still, it's messy. =A0If only because various trees might be running >> > untested combinations of patches. =A0Can we get these all into the sam= e >> > tree? =A0Paul's? >> > >> #1 is a bit tricky. cris has already merged the pgprot_noncached() patch= , >> which means only m32r and xtensa are outstanding, and unfortunately >> neither one of those is very fast to pick up changes. OTOH, both of thos= e >> do include asm-generic/pgtable.h, so the build shouldn't break in -next >> for those two if I merge #2 and #3, even if the behaviour won't be >> correct for those platforms until they merge their pgprot_noncached() >> patches (I think this is ok, since it's not changing any behaviour they >> experience today anyways). >> >> It would be nice to have an ack from someone for #2 before merging it, >> but it's been out there long enough that people have had ample time to >> raise objections. >> >> So I'll make this the last call for acks or nacks on #2 and #3, if none >> show up in the next couple of days, I'll fold them in to my tree and >> they'll show up in -next starting next week. > > Well my head span off ages ago. =A0Could someone please resend all three > patches? > > > > I don't really understand that one. =A0Have we heard fro Jaya recently? Some f_op->mmap() callbacks invoked from mmap_region() may want to use writenotify but also modify vma->vm_page_prot to for instance mark the vma as uncached. Without patch #2 the vma->vm_page_prot value set by f_op->mmap() gets overwritten if writenotify is enabled. So in the case of writenotify the vma will never be uncached even though f_op->mmap() marks it as such. Patch #2 makes it possible to keep the uncached setting made by f_op->mmap() and use writenotify. On SuperH we want to use deferred io with an uncached vma, so patch #3 makes sure our arch specific fb_pgprotect() function gets called so we can mark the vma as uncached. Hope this clarifies a bit. / magnus -- 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