From patchwork Mon Apr 22 00:48:47 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wei Yang X-Patchwork-Id: 10910557 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 49201161F for ; Mon, 22 Apr 2019 00:56:07 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 3DDDF286B3 for ; Mon, 22 Apr 2019 00:56:07 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 2F70D286CF; Mon, 22 Apr 2019 00:56:07 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 871E2286B3 for ; Mon, 22 Apr 2019 00:56:06 +0000 (UTC) Received: from localhost ([127.0.0.1]:58833 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hINFd-00009x-PK for patchwork-qemu-devel@patchwork.kernel.org; Sun, 21 Apr 2019 20:56:05 -0400 Received: from eggs.gnu.org ([209.51.188.92]:41629) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hINEd-0007lR-Mu for qemu-devel@nongnu.org; Sun, 21 Apr 2019 20:55:05 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hINEc-0003do-5L for qemu-devel@nongnu.org; Sun, 21 Apr 2019 20:55:03 -0400 Received: from mga05.intel.com ([192.55.52.43]:45606) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hINEb-0003ci-TP for qemu-devel@nongnu.org; Sun, 21 Apr 2019 20:55:02 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga004.jf.intel.com ([10.7.209.38]) by fmsmga105.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 21 Apr 2019 17:54:59 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.60,379,1549958400"; d="scan'208";a="293416706" Received: from richard.sh.intel.com (HELO localhost) ([10.239.159.54]) by orsmga004.jf.intel.com with ESMTP; 21 Apr 2019 17:49:57 -0700 From: Wei Yang To: qemu-devel@nongnu.org Date: Mon, 22 Apr 2019 08:48:47 +0800 Message-Id: <20190422004849.26463-1-richardw.yang@linux.intel.com> X-Mailer: git-send-email 2.19.1 MIME-Version: 1.0 X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 192.55.52.43 Subject: [Qemu-devel] [PATCH v14 0/2] support MAP_SYNC for memory-backend-file X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: pagupta@redhat.com, xiaoguangrong.eric@gmail.com, mst@redhat.com, yi.z.zhang@linux.intel.com, yu.c.zhang@linux.intel.com, richardw.yang@linux.intel.com, stefanha@redhat.com, imammedo@redhat.com, pbonzini@redhat.com, dan.j.williams@intel.com, ehabkost@redhat.com Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP Linux 4.15 introduces a new mmap flag MAP_SYNC, which can be used to guarantee the write persistence to mmap'ed files supporting DAX (e.g., files on ext4/xfs file system mounted with '-o dax'). A description of MAP_SYNC and MAP_SHARED_VALIDATE can be found at https://patchwork.kernel.org/patch/10028151/ In order to make sure that the file metadata is in sync after a fault while we are writing a shared DAX supporting backend files, this patch-set enables QEMU to use MAP_SYNC flag for memory-backend-dax-file. As the DAX vs DMA truncated issue was solved, we refined the code and send out this feature for the v5 version. We will pass MAP_SYNC to mmap(2); if MAP_SYNC is supported and 'share=on' & 'pmem=on'. Or QEMU will not pass this flag to mmap(2) Test with below cases: 1. pmem=on is set, shared=on is set, MAP_SYNC supported: a: backend is a dax supporting file. 1) start VM1 with options: -object memory-backend-file,id=nv_be4,share,mem-path=${DAX_FILE_1},size=${DAX_FILE_SIZE_1},align=128M,pmem=on,share=on -device nvdimm,id=nv4,memdev=nv_be4,label-size=2M. 2) start VM2 with options: -object memory-backend-file,id=nv_be4,share,mem-path=${DAX_FILE_2,size=${DAX_FILE_SIZE_2},align=128M,pmem=on,share=on -device nvdimm,id=nv4,memdev=nv_be4,label-size=2M. 3) live migrate from VM1 to VM2. 4) Suddenly let Host crash or power failure. 5) check DAX_FILE_1 and DAX_FILE_2, no corrupt. b: backend is a regular file. 1) start with options -object memory-backend-file,id=nv_be4,share,mem-path=${REG_FILE},size=${REG_FILE_SIZE},align=128M,pmem=on,share=on -device nvdimm,id=nv4,memdev=nv_be4,label-size=2M. will warning "failed to validate with mapping flags: Operation not supported" FILE_1 and FILE_2 random corrupt. 2. Other cases: FILE_1 and FILE_2 random corrupt. Changes in V14: * 1/2 rebase on top of current upstream and tested Changes in V13: * 4/5 Micheal: move the inlcude to mmap_alloc.c. * 4/5 Micheal: refine the warning message. * 5/5 Micheal: refine the Documentations. Changes in V12: * 2/5: Micheal: Update update-linux-headers.sh * 3/5: Micheal: Use script update add linux/mman.h * 4/5: Pankaj,Micheal: 1) fallback to mmap without MAP_SYNC & MAP_SHARED_VALIDATE if sync not supported or failed 2) Replace the include with 3/5 added linux/mman.h * 5/5: Micheal: Refine the Documentations. Changes in V11: * 1/3: Micheal: Change to just add a bool is_pmem in qemu_ram_mmap. * 2/3: Micheal: Fix the compatibility for old kernel. * 2/3&3/3: Micheal&Eduardo :Update the behavior below: Waning at no-dax and continue without MAP_SYNC. Test if fails again for compatibility, then remove the MAP_VALIDATE and silently proceed. Changes in V10: * 4/4: refine the document. * 3/4: Reviewed-by: Stefano Garzarella * 2/4: refine the commit message, Added MAP_SHARED_VALIDATE. * 2/4: Fix the wrong include header Changes in V9: * 1/6: Reviewed-by: Eduardo Habkost * 2/6: New Added: Micheal: use sparse feature define RAM_FLAG. since I don't have much knowledge about the sparse feature, @Micheal Could you add some documentation/commit message on this patch? Thank you very much. * 3/6: from 2/5: Eduardo: updated the commit message. * 4/6: from 3/5: Micheal: don't ignore MAP_SYNC failures silently. * 5/6: from 4/5: Eduardo: updated the commit message. * 6/6: from 5/5: Micheal: Drop the sync option, document the MAP_SYNC. Changes in v8: * Micheal: 3/5, remove the duplicated define in the os_dep.h * Micheal: 2/5, make type define safety. * Micheal: 2/5, fixed the incorrect define MAP_SHARE on qemu_anon_ram_alloc. * 4/6 removed, we remove the on/off/auto define of sync, as by now, MAP_SYNC only worked with pmem=on. * @Micheal, I still reuse the RAM_SYNC flag, it is much straightforward to parse all the flags in one parameter. Changes in v7: * Micheal: [3,4,6]/6 limited the "sync" flag only on a nvdimm backend.(pmem=on) Changes in v6: * Pankaj: 3/7 are squashed with 2/7 * Pankaj: 7/7 update comments to "consistent filesystem metadata". * Pankaj, Igor: 1/7 Added Reviewed-by in patch-1/7 * Stefan, 4/7 move the include header from "/linux/mman.h" to "osdep.h" * Stefan, 5/7 Add missing "munmap" * Stefan, 2/7 refine the shared/flag. Changes in v5: * Add patch 1 to fix a memory leak issue. * Refine the patch 4-6 * Remove the patch 3 as we already change the parameter from "shared" to "flags" Changes in v4: * Add patch 1-3 to switch some functions to a single 'flags' parameters. (Michael S. Tsirkin) * v3 patch 1-3 become v4 patch 4-6. * Patch 4: move definitions of MAP_SYNC and MAP_SHARED_VALIDATE to a new header file under include/standard-headers/linux/. (Michael S. Tsirkin) * Patch 6: refine the description of the 'sync' option. (Michael S. Tsirkin) Changes in v3: * Patch 1: add MAP_SHARED_VALIDATE in both sync=on and sync=auto cases, and add back the retry mechanism. MAP_SYNC will be ignored by Linux kernel 4.15 if MAP_SHARED_VALIDATE is missed. * Patch 1: define MAP_SYNC and MAP_SHARED_VALIDATE as 0 on non-Linux platforms in order to make qemu_ram_mmap() compile on those platforms. * Patch 2&3: include more information in error messages of memory-backend in hope to help user to identify the error. (Dr. David Alan Gilbert) * Patch 3: fix typo in the commit message. (Dr. David Alan Gilbert) Changes in v2: * Add 'sync' option to control the use of MAP_SYNC. (Eduardo Habkost) * Remove the unnecessary set of MAP_SHARED_VALIDATE in some cases and the retry mechanism in qemu_ram_mmap(). (Michael S. Tsirkin) * Move OS dependent definitions of MAP_SYNC and MAP_SHARED_VALIDATE to osdep.h. (Michael S. Tsirkin) Zhang Yi (2): util/mmap-alloc: support MAP_SYNC in qemu_ram_mmap() docs: Added MAP_SYNC documentation docs/nvdimm.txt | 22 +++++++++++++++++++--- qemu-options.hx | 5 +++++ util/mmap-alloc.c | 41 ++++++++++++++++++++++++++++++++++++++++- 3 files changed, 64 insertions(+), 4 deletions(-) Reviewed-by: Michael S. Tsirkin