From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([209.51.188.92]:44221) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hIlOA-0001ov-Cy for qemu-devel@nongnu.org; Mon, 22 Apr 2019 22:42:31 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hIlO9-0001zO-5z for qemu-devel@nongnu.org; Mon, 22 Apr 2019 22:42:30 -0400 Received: from mga03.intel.com ([134.134.136.65]:43349) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hIlO8-0001wZ-UZ for qemu-devel@nongnu.org; Mon, 22 Apr 2019 22:42:29 -0400 Date: Tue, 23 Apr 2019 10:41:51 +0800 From: Wei Yang Message-ID: <20190423024151.GA10783@richard> Reply-To: Wei Yang References: <20190422004849.26463-1-richardw.yang@linux.intel.com> <20190422083013-mutt-send-email-mst@kernel.org> <20190422182255.GV25134@habkost.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190422182255.GV25134@habkost.net> Subject: Re: [Qemu-devel] [PATCH v14 0/2] support MAP_SYNC for memory-backend-file List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Eduardo Habkost Cc: "Michael S. Tsirkin" , Wei Yang , qemu-devel@nongnu.org, xiaoguangrong.eric@gmail.com, stefanha@redhat.com, pbonzini@redhat.com, pagupta@redhat.com, yu.c.zhang@linux.intel.com, imammedo@redhat.com, dan.j.williams@intel.com, yi.z.zhang@linux.intel.com On Mon, Apr 22, 2019 at 03:22:55PM -0300, Eduardo Habkost wrote: >On Mon, Apr 22, 2019 at 08:34:51AM -0400, Michael S. Tsirkin wrote: >> On Mon, Apr 22, 2019 at 08:48:47AM +0800, Wei Yang wrote: >> > 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) >> >> OK this is in a good shape. As we are in freeze anyway, >> there's still a bit more time to polish it. I have a couple of >> suggestions: >> >> - squash docs in same patch with code, no need for two patches >> - mmap errors are not silently ignored as the doc says, >> a warning is produced > >Note that a warning is produced only if both share=on and pmem=on >is specified. If using pmem=on without share=on, no warning is >printed at all. > >I agree we could squash the docs in the same patch, but I don't >want to prevent the code from being merged and require v15 to be >sent just because we are still polishing the documentation. > >If there are no objections, I plan to apply this version of the >series including the following fixup (just removing the word >"silently"), and I suggest further improvements to be sent as >follow up patches. > If my understanding is correct, the following up patch is: "send the warnings to an errp object and not stderr" -- Wei Yang Help you, Help me From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.4 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 34EE7C10F11 for ; Tue, 23 Apr 2019 02:43:21 +0000 (UTC) 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.kernel.org (Postfix) with ESMTPS id F1371206BA for ; Tue, 23 Apr 2019 02:43:20 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F1371206BA Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([127.0.0.1]:47063 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hIlOx-0002Bj-Qz for qemu-devel@archiver.kernel.org; Mon, 22 Apr 2019 22:43:19 -0400 Received: from eggs.gnu.org ([209.51.188.92]:44221) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hIlOA-0001ov-Cy for qemu-devel@nongnu.org; Mon, 22 Apr 2019 22:42:31 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hIlO9-0001zO-5z for qemu-devel@nongnu.org; Mon, 22 Apr 2019 22:42:30 -0400 Received: from mga03.intel.com ([134.134.136.65]:43349) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hIlO8-0001wZ-UZ for qemu-devel@nongnu.org; Mon, 22 Apr 2019 22:42:29 -0400 X-Amp-Result: UNSCANNABLE X-Amp-File-Uploaded: False Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by orsmga103.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 22 Apr 2019 19:42:22 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.60,384,1549958400"; d="scan'208";a="151518380" Received: from richard.sh.intel.com (HELO localhost) ([10.239.159.54]) by FMSMGA003.fm.intel.com with ESMTP; 22 Apr 2019 19:42:18 -0700 Date: Tue, 23 Apr 2019 10:41:51 +0800 From: Wei Yang To: Eduardo Habkost Message-ID: <20190423024151.GA10783@richard> References: <20190422004849.26463-1-richardw.yang@linux.intel.com> <20190422083013-mutt-send-email-mst@kernel.org> <20190422182255.GV25134@habkost.net> MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline In-Reply-To: <20190422182255.GV25134@habkost.net> User-Agent: Mutt/1.10.1 (2018-07-13) X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 134.134.136.65 Subject: Re: [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: , Reply-To: Wei Yang Cc: pagupta@redhat.com, xiaoguangrong.eric@gmail.com, "Michael S. Tsirkin" , qemu-devel@nongnu.org, yi.z.zhang@linux.intel.com, yu.c.zhang@linux.intel.com, Wei Yang , stefanha@redhat.com, imammedo@redhat.com, pbonzini@redhat.com, dan.j.williams@intel.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Message-ID: <20190423024151.r7GydGnU87pOsceVqhXFypVs3mpRk8NBfm1D764RuLU@z> On Mon, Apr 22, 2019 at 03:22:55PM -0300, Eduardo Habkost wrote: >On Mon, Apr 22, 2019 at 08:34:51AM -0400, Michael S. Tsirkin wrote: >> On Mon, Apr 22, 2019 at 08:48:47AM +0800, Wei Yang wrote: >> > 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) >> >> OK this is in a good shape. As we are in freeze anyway, >> there's still a bit more time to polish it. I have a couple of >> suggestions: >> >> - squash docs in same patch with code, no need for two patches >> - mmap errors are not silently ignored as the doc says, >> a warning is produced > >Note that a warning is produced only if both share=on and pmem=on >is specified. If using pmem=on without share=on, no warning is >printed at all. > >I agree we could squash the docs in the same patch, but I don't >want to prevent the code from being merged and require v15 to be >sent just because we are still polishing the documentation. > >If there are no objections, I plan to apply this version of the >series including the following fixup (just removing the word >"silently"), and I suggest further improvements to be sent as >follow up patches. > If my understanding is correct, the following up patch is: "send the warnings to an errp object and not stderr" -- Wei Yang Help you, Help me