From mboxrd@z Thu Jan 1 00:00:00 1970 From: Trond Myklebust Subject: Re: still nfs problems [Was: Linux 2.6.37-rc8] Date: Wed, 05 Jan 2011 16:16:48 -0500 Message-ID: <1294262208.2952.4.camel@heimdal.trondhjem.org> References: <1294254337.16957.13.camel@mulgrave.site> <1294256169.16957.18.camel@mulgrave.site> <20110105200008.GJ8638@n2100.arm.linux.org.uk> <1294259637.16957.25.camel@mulgrave.site> <20110105210448.GM8638@n2100.arm.linux.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT Return-path: In-Reply-To: Sender: linux-nfs-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Linus Torvalds Cc: Russell King - ARM Linux , James Bottomley , linux-nfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Marc Kleine-Budde , Uwe =?ISO-8859-1?Q?Kleine-K=F6nig?= , Marc Kleine-Budde , linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, Parisc List , linux-arch-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-arch.vger.kernel.org On Wed, 2011-01-05 at 13:08 -0800, Linus Torvalds wrote: > On Wed, Jan 5, 2011 at 1:04 PM, Russell King - ARM Linux > wrote: > > On Wed, Jan 05, 2011 at 12:48:32PM -0800, Linus Torvalds wrote: > >> (You can also force the problem with vmalloc() an then following the > >> kernel page tables, but I hope nobody does that any more. I suspect > >> I'm wrong, though, there's probably code that mixes vmalloc and > >> physical page accesses in various drivers) > > > > Should vmalloc_to_page() (84 users)/vmalloc_to_pfn() (17 users) be > > deprecated then? ;) > > I do think that the "modern" way of doing it is > "vmap()"/"vm_map_ram()" and friends, and it should be preferred over > using vmalloc() and then looking up the pages. > > But in the end, the two approaches really are equivalent, so it's not > like it really matters. So I don't think we need to deprecate things > officially, but obviously we should make people more aware of the > whole virtual alias thing that crops up whenever you use any of these > approaches. So what should be the preferred way to ensure data gets flushed when you've written directly to a page, and then want to read through the vm_map_ram() virtual range? Should we be adding new semantics to flush_kernel_dcache_page()? -- Trond Myklebust Linux NFS client maintainer NetApp Trond.Myklebust-HgOvQuBEEgTQT0dZR+AlfA@public.gmane.org www.netapp.com -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx2.netapp.com ([216.240.18.37]:19326 "EHLO mx2.netapp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752817Ab1AEVQ7 convert rfc822-to-8bit (ORCPT ); Wed, 5 Jan 2011 16:16:59 -0500 Subject: Re: still nfs problems [Was: Linux 2.6.37-rc8] From: Trond Myklebust In-Reply-To: References: <1294254337.16957.13.camel@mulgrave.site> <1294256169.16957.18.camel@mulgrave.site> <20110105200008.GJ8638@n2100.arm.linux.org.uk> <1294259637.16957.25.camel@mulgrave.site> <20110105210448.GM8638@n2100.arm.linux.org.uk> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT Date: Wed, 05 Jan 2011 16:16:48 -0500 Message-ID: <1294262208.2952.4.camel@heimdal.trondhjem.org> Mime-Version: 1.0 Sender: linux-arch-owner@vger.kernel.org List-ID: To: Linus Torvalds Cc: Russell King - ARM Linux , James Bottomley , linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org, Marc Kleine-Budde , Uwe =?ISO-8859-1?Q?Kleine-K=F6nig?= , Marc Kleine-Budde , linux-arm-kernel@lists.infradead.org, Parisc List , linux-arch@vger.kernel.org Message-ID: <20110105211648.MWeIUJLDTxrq__-69NomBtMSZ9vwoiONb8cr6VvNdWk@z> On Wed, 2011-01-05 at 13:08 -0800, Linus Torvalds wrote: > On Wed, Jan 5, 2011 at 1:04 PM, Russell King - ARM Linux > wrote: > > On Wed, Jan 05, 2011 at 12:48:32PM -0800, Linus Torvalds wrote: > >> (You can also force the problem with vmalloc() an then following the > >> kernel page tables, but I hope nobody does that any more. I suspect > >> I'm wrong, though, there's probably code that mixes vmalloc and > >> physical page accesses in various drivers) > > > > Should vmalloc_to_page() (84 users)/vmalloc_to_pfn() (17 users) be > > deprecated then? ;) > > I do think that the "modern" way of doing it is > "vmap()"/"vm_map_ram()" and friends, and it should be preferred over > using vmalloc() and then looking up the pages. > > But in the end, the two approaches really are equivalent, so it's not > like it really matters. So I don't think we need to deprecate things > officially, but obviously we should make people more aware of the > whole virtual alias thing that crops up whenever you use any of these > approaches. So what should be the preferred way to ensure data gets flushed when you've written directly to a page, and then want to read through the vm_map_ram() virtual range? Should we be adding new semantics to flush_kernel_dcache_page()? -- Trond Myklebust Linux NFS client maintainer NetApp Trond.Myklebust@netapp.com www.netapp.com