From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Thu, 16 Mar 2017 00:18:59 +0100 (CET) Received: from mail-wm0-x244.google.com ([IPv6:2a00:1450:400c:c09::244]:33590 "EHLO mail-wm0-x244.google.com" rhost-flags-OK-OK-OK-OK) by eddie.linux-mips.org with ESMTP id S23992111AbdCOXSwlIjwK (ORCPT ); Thu, 16 Mar 2017 00:18:52 +0100 Received: by mail-wm0-x244.google.com with SMTP id n11so7059034wma.0; Wed, 15 Mar 2017 16:18:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=googlemail.com; s=20161025; h=from:date:to:cc:subject:message-id:mail-followup-to:mime-version :content-disposition:in-reply-to:user-agent; bh=5cTOrRSbVEFPsTsy4MpkXreWhHtQFFmjceLO4PaXjU4=; b=OgRrkAJXzwQeK8ZiJfz7HWMHrxfvHW097fGc48HC9Fm8emwBC/XFnZ5QIb696If7kL sP6NPwFc8xrtyCizZH9s6ldPIo1TjLjOSHHEmB+PElWkbAgjjc1QnwGmiQ2RhvVqs0oI jftC/Xl/5AFFXjGU23nHVEAM9oUZhIs1NFtuNOZ1Vggx21Xzw6hUq+G40QgCs3Bo7cAe uZt888JQosd7uQTFDQxfRy4YY7T0duV0+wifNPS9nWtepVOyGntIwhQBOxmpeObbnRp4 zMnQs6bn4W8VLcBlVflD2qcM84CNHtqXx+ujQgMaNpU6bzpXUojFFExKutwb0eodsgnN x0Ew== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:date:to:cc:subject:message-id :mail-followup-to:mime-version:content-disposition:in-reply-to :user-agent; bh=5cTOrRSbVEFPsTsy4MpkXreWhHtQFFmjceLO4PaXjU4=; b=Y3wTuTMMfxtPx3iS7P4lWhNBLEsNs+SQl4/YBLMgCpSWpMJ72pw+ZXPGD7j3ebytdA wsiPt3tKl6TXfyVo26CziMET0PViQ0Uc12gHRL5Jlbtgdn+SucS2MV58cDPBCqyIPs9n wfburStQTL7rO3J7aMa7kpbOA1eX908guzdHwlg+E3iET+BeYwf8LX5NWg1WiIdMiSaJ +ycI30hd/yIRiAX+pObL+FTI7joUL9630U34ECJ1ZQcKjU1I7LpXmimNDfu2QqKND5HR 98Vnw3yawW0gBME3VpVMJdP1IaJsXC3UNT/qhZd0fyHCRu1C/QBJj4a3sx8CQ+wLFBB8 sRdA== X-Gm-Message-State: AFeK/H2kTOQezlzcNOPasOGiosoT0F+dY6F2fyNhqAp6HhMCW71Ik9Hsaq5zEO8ydMf92g== X-Received: by 10.28.216.208 with SMTP id p199mr6397101wmg.44.1489619927312; Wed, 15 Mar 2017 16:18:47 -0700 (PDT) Received: from localhost (login1.zih.tu-dresden.de. [141.76.16.140]) by smtp.googlemail.com with ESMTPSA id o15sm2126811wmd.10.2017.03.15.16.18.45 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Wed, 15 Mar 2017 16:18:45 -0700 (PDT) From: Till Smejkal X-Google-Original-From: Till Smejkal Date: Wed, 15 Mar 2017 16:18:43 -0700 To: "Luck, Tony" Cc: Andy Lutomirski , Andy Lutomirski , Till Smejkal , Richard Henderson , Ivan Kokshaysky , Matt Turner , Vineet Gupta , Russell King , Catalin Marinas , Will Deacon , Steven Miao , Richard Kuo , Fenghua Yu , James Hogan , Ralf Baechle , "James E.J. Bottomley" , Helge Deller , Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Martin Schwidefsky , Heiko Carstens , Yoshinori Sato , Rich Felker , "David S. Miller" , Chris Metcalf , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , X86 ML , Chris Zankel , Max Filippov , Arnd Bergmann , Greg Kroah-Hartman , Laurent Pinchart , Mauro Carvalho Chehab , Pawel Osciak , Marek Szyprowski , Kyungmin Park , David Woodhouse , Brian Norris , Boris Brezillon , Marek Vasut , Richard Weinberger , Cyrille Pitchen , Felipe Balbi , Alexander Viro , Benjamin LaHaise , Nadia Yvette Chambers , Jeff Layton , "J. Bruce Fields" , Peter Zijlstra , Hugh Dickins , Arnaldo Carvalho de Melo , Alexander Shishkin , Jaroslav Kysela , Takashi Iwai , "linux-kernel@vger.kernel.org" , linux-alpha@vger.kernel.org, arcml , "linux-arm-kernel@lists.infradead.org" , adi-buildroot-devel@lists.sourceforge.net, linux-hexagon@vger.kernel.org, "linux-ia64@vger.kernel.org" , linux-metag@vger.kernel.org, Linux MIPS Mailing List , linux-parisc@vger.kernel.org, linuxppc-dev , "linux-s390@vger.kernel.org" , "linux-sh@vger.kernel.org" , sparclinux@vger.kernel.org, linux-xtensa@linux-xtensa.org, Linux Media Mailing List , linux-mtd@lists.infradead.org, USB list , Linux FS Devel , linux-aio@kvack.org, "linux-mm@kvack.org" , Linux API , linux-arch , ALSA development Subject: Re: [RFC PATCH 00/13] Introduce first class virtual address spaces Message-ID: <20170315231843.sgxzg6qj34anyirs@arch-dev> Mail-Followup-To: "Luck, Tony" , Andy Lutomirski , Andy Lutomirski , Till Smejkal , Richard Henderson , Ivan Kokshaysky , Matt Turner , Vineet Gupta , Russell King , Catalin Marinas , Will Deacon , Steven Miao , Richard Kuo , Fenghua Yu , James Hogan , Ralf Baechle , "James E.J. Bottomley" , Helge Deller , Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Martin Schwidefsky , Heiko Carstens , Yoshinori Sato , Rich Felker , "David S. Miller" , Chris Metcalf , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , X86 ML , Chris Zankel , Max Filippov , Arnd Bergmann , Greg Kroah-Hartman , Laurent Pinchart , Mauro Carvalho Chehab , Pawel Osciak , Marek Szyprowski , Kyungmin Park , David Woodhouse , Brian Norris , Boris Brezillon , Marek Vasut , Richard Weinberger , Cyrille Pitchen , Felipe Balbi , Alexander Viro , Benjamin LaHaise , Nadia Yvette Chambers , Jeff Layton , "J. Bruce Fields" , Peter Zijlstra , Hugh Dickins , Arnaldo Carvalho de Melo , Alexander Shishkin , Jaroslav Kysela , Takashi Iwai , "linux-kernel@vger.kernel.org" , linux-alpha@vger.kernel.org, arcml , "linux-arm-kernel@lists.infradead.org" , adi-buildroot-devel@lists.sourceforge.net, linux-hexagon@vger.kernel.org, "linux-ia64@vger.kernel.org" , linux-metag@vger.kernel.org, Linux MIPS Mailing List , linux-parisc@vger.kernel.org, linuxppc-dev , "linux-s390@vger.kernel.org" , "linux-sh@vger.kernel.org" , sparclinux@vger.kernel.org, linux-xtensa@linux-xtensa.org, Linux Media Mailing List , linux-mtd@lists.infradead.org, USB list , Linux FS Devel , linux-aio@kvack.org, "linux-mm@kvack.org" , Linux API , linux-arch , ALSA development MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170315220952.GA1435@intel.com> User-Agent: NeoMutt/20170306 (1.8.0) Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 57314 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: till.smejkal@googlemail.com Precedence: bulk List-help: List-unsubscribe: List-software: Ecartis version 1.0.0 List-Id: linux-mips X-List-ID: linux-mips List-subscribe: List-owner: List-post: List-archive: X-list: linux-mips On Wed, 15 Mar 2017, Luck, Tony wrote: > On Wed, Mar 15, 2017 at 03:02:34PM -0700, Till Smejkal wrote: > > I don't agree here. VAS segments are basically in-memory files that are handled by > > the kernel directly without using a file system. Hence, if an application uses a VAS > > segment to store data the same rules apply as if it uses a file. Everything that it > > saves in the VAS segment might be accessible by other applications. An application > > using VAS segments should be aware of this fact. In addition, the resources that are > > represented by a VAS segment are not leaked. As I said, VAS segments are much like > > files. Hence, if you don't want to use them any more, delete them. But as with files, > > the kernel will not delete them for you (although something like this can be added). > > So how do they differ from shmget(2), shmat(2), shmdt(2), shmctl(2)? > > Apart from VAS having better names, instead of silly "key_t key" ones. Unfortunately, I have to admit that the VAS segments don't differ from shm* a lot. The implementation is differently, but the functionality that you can achieve with it is very similar. I am sorry. We should have looked more closely at the whole functionality that is provided by the shmem subsystem before working on VAS segments. However, VAS segments are not the key part of this patch set. The more interesting functionality in our opinion is the introduction of first class virtual address spaces and what they can be used for. VAS segments were just another logical step for us (from first class virtual address spaces to first class virtual address space segments) but since their functionality can be achieved with various other already existing features of the Linux kernel, I will probably drop them in future versions of the patchset. Thanks Till From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm0-x244.google.com ([IPv6:2a00:1450:400c:c09::244]:33590 "EHLO mail-wm0-x244.google.com" rhost-flags-OK-OK-OK-OK) by eddie.linux-mips.org with ESMTP id S23992111AbdCOXSwlIjwK (ORCPT ); Thu, 16 Mar 2017 00:18:52 +0100 From: Till Smejkal Date: Wed, 15 Mar 2017 16:18:43 -0700 Subject: Re: [RFC PATCH 00/13] Introduce first class virtual address spaces Message-ID: <20170315231843.sgxzg6qj34anyirs@arch-dev> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170315220952.GA1435@intel.com> Return-Path: Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org List-help: List-unsubscribe: List-software: Ecartis version 1.0.0 List-subscribe: List-owner: List-post: List-archive: To: "Luck, Tony" Cc: Andy Lutomirski , Andy Lutomirski , Till Smejkal , Richard Henderson , Ivan Kokshaysky , Matt Turner , Vineet Gupta , Russell King , Catalin Marinas , Will Deacon , Steven Miao , Richard Kuo , Fenghua Yu , James Hogan , Ralf Baechle , "James E.J. Bottomley" , Helge Deller , Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Martin Schwidefsky , Heiko Carstens , Yoshinori Sato , Rich Felker , "David S. Miller" , Chris Metcalf , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , X86 ML , Chris Zankel , Max Filippov , Arnd Bergmann , Greg Kroah-Hartman , Laurent Pinchart , Mauro Carvalho Chehab , Pawel Osciak , Marek Szyprowski , Kyungmin Park , David Woodhouse , Brian Norris , Boris Brezillon , Marek Vasut , Richard Weinberger , Cyrille Pitchen , Felipe Balbi , Alexander Viro , Benjamin LaHaise , Nadia Yvette Chambers , Jeff Layton , "J. Bruce Fields" , Peter Zijlstra , Hugh Dickins , Arnaldo Carvalho de Melo , Alexander Shishkin , Jaroslav Kysela , Takashi Iwai , "linux-kernel@vger.kernel.org" , linux-alpha@vger.kernel.org, arcml , "linux-arm-kernel@lists.infradead.org" , adi-buildroot-devel@lists.sourceforge.net, linux-hexagon@vger.kernel.org, "linux-ia64@vger.kernel.org" , linux-metag@vger.kernel.org, Linux MIPS Mailing List , linux-parisc@vger.kernel.org, linuxppc-dev , "linux-s390@vger.kernel.org" , "linux-sh@vger.kernel.org" , sparclinux@vger.kernel.org, linux-xtensa@linux-xtensa.org, Linux Media Mailing List , linux-mtd@lists.infradead.org, USB list , Linux FS Devel , linux-aio@kvack.org, "linux-mm@kvack.org" , Linux API , linux-arch , ALSA development Message-ID: <20170315231843.yMZOGRalw16Zt6em9HJ-SAF47WhRqVNT5Ggtu7GVVE0@z> On Wed, 15 Mar 2017, Luck, Tony wrote: > On Wed, Mar 15, 2017 at 03:02:34PM -0700, Till Smejkal wrote: > > I don't agree here. VAS segments are basically in-memory files that are handled by > > the kernel directly without using a file system. Hence, if an application uses a VAS > > segment to store data the same rules apply as if it uses a file. Everything that it > > saves in the VAS segment might be accessible by other applications. An application > > using VAS segments should be aware of this fact. In addition, the resources that are > > represented by a VAS segment are not leaked. As I said, VAS segments are much like > > files. Hence, if you don't want to use them any more, delete them. But as with files, > > the kernel will not delete them for you (although something like this can be added). > > So how do they differ from shmget(2), shmat(2), shmdt(2), shmctl(2)? > > Apart from VAS having better names, instead of silly "key_t key" ones. Unfortunately, I have to admit that the VAS segments don't differ from shm* a lot. The implementation is differently, but the functionality that you can achieve with it is very similar. I am sorry. We should have looked more closely at the whole functionality that is provided by the shmem subsystem before working on VAS segments. However, VAS segments are not the key part of this patch set. The more interesting functionality in our opinion is the introduction of first class virtual address spaces and what they can be used for. VAS segments were just another logical step for us (from first class virtual address spaces to first class virtual address space segments) but since their functionality can be achieved with various other already existing features of the Linux kernel, I will probably drop them in future versions of the patchset. Thanks Till