From patchwork Mon Apr 22 00:48:48 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wei Yang X-Patchwork-Id: 10910559 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 83A01922 for ; Mon, 22 Apr 2019 00:57:34 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 74FAA286CF for ; Mon, 22 Apr 2019 00:57:34 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 657E4286CD; Mon, 22 Apr 2019 00:57:34 +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 ED539286CD for ; Mon, 22 Apr 2019 00:57:33 +0000 (UTC) Received: from localhost ([127.0.0.1]:58843 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hINH3-00018S-Bq for patchwork-qemu-devel@patchwork.kernel.org; Sun, 21 Apr 2019 20:57:33 -0400 Received: from eggs.gnu.org ([209.51.188.92]:41627) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hINEd-0007lQ-MW for qemu-devel@nongnu.org; Sun, 21 Apr 2019 20:55:04 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hINEc-0003dy-K2 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 1hINEc-0003ci-CM 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 17:55:00 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.60,379,1549958400"; d="scan'208";a="293416722" Received: from richard.sh.intel.com (HELO localhost) ([10.239.159.54]) by orsmga004.jf.intel.com with ESMTP; 21 Apr 2019 17:50:00 -0700 From: Wei Yang To: qemu-devel@nongnu.org Date: Mon, 22 Apr 2019 08:48:48 +0800 Message-Id: <20190422004849.26463-2-richardw.yang@linux.intel.com> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190422004849.26463-1-richardw.yang@linux.intel.com> References: <20190422004849.26463-1-richardw.yang@linux.intel.com> 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 1/2] util/mmap-alloc: support MAP_SYNC in qemu_ram_mmap() 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, Haozhong Zhang , 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 From: Zhang Yi When a file supporting DAX is used as vNVDIMM backend, mmap it with MAP_SYNC flag in addition which can ensure file system metadata synced in each guest writes to the backend file, without other QEMU actions (e.g., periodic fsync() by QEMU). Current, We have below different possible use cases: 1. pmem=on is set, shared=on is set, MAP_SYNC supported: a: backend is a dax supporting file. - MAP_SYNC will active. b: backend is not a dax supporting file. - mmap will trigger a warning. then MAP_SYNC flag will be ignored 2. The rest of cases: - we will never pass the MAP_SYNC to mmap2 Signed-off-by: Haozhong Zhang Signed-off-by: Zhang Yi [ehabkost: Rebased patch to latest code on master] Signed-off-by: Eduardo Habkost Signed-off-by: Wei Yang Tested-by: Wei Yang Reviewed-by: Stefan Hajnoczi --- v14: rebase on top of current upstream --- util/mmap-alloc.c | 41 ++++++++++++++++++++++++++++++++++++++++- 1 file changed, 40 insertions(+), 1 deletion(-) diff --git a/util/mmap-alloc.c b/util/mmap-alloc.c index 9713f4b960..f7f177d0ea 100644 --- a/util/mmap-alloc.c +++ b/util/mmap-alloc.c @@ -10,6 +10,13 @@ * later. See the COPYING file in the top-level directory. */ +#ifdef CONFIG_LINUX +#include +#else /* !CONFIG_LINUX */ +#define MAP_SYNC 0x0 +#define MAP_SHARED_VALIDATE 0x0 +#endif /* CONFIG_LINUX */ + #include "qemu/osdep.h" #include "qemu/mmap-alloc.h" #include "qemu/host-utils.h" @@ -82,6 +89,7 @@ void *qemu_ram_mmap(int fd, bool is_pmem) { int flags; + int map_sync_flags = 0; int guardfd; size_t offset; size_t pagesize; @@ -132,9 +140,40 @@ void *qemu_ram_mmap(int fd, flags = MAP_FIXED; flags |= fd == -1 ? MAP_ANONYMOUS : 0; flags |= shared ? MAP_SHARED : MAP_PRIVATE; + if (shared && is_pmem) { + map_sync_flags = MAP_SYNC | MAP_SHARED_VALIDATE; + } + offset = QEMU_ALIGN_UP((uintptr_t)guardptr, align) - (uintptr_t)guardptr; - ptr = mmap(guardptr + offset, size, PROT_READ | PROT_WRITE, flags, fd, 0); + ptr = mmap(guardptr + offset, size, PROT_READ | PROT_WRITE, + flags | map_sync_flags, fd, 0); + + if (ptr == MAP_FAILED && map_sync_flags) { + if (errno == ENOTSUP) { + char *proc_link, *file_name; + int len; + proc_link = g_strdup_printf("/proc/self/fd/%d", fd); + file_name = g_malloc0(PATH_MAX); + len = readlink(proc_link, file_name, PATH_MAX - 1); + if (len < 0) { + len = 0; + } + file_name[len] = '\0'; + fprintf(stderr, "Warning: requesting persistence across crashes " + "for backend file %s failed. Proceeding without " + "persistence, data might become corrupted in case of host " + "crash.\n", file_name); + g_free(proc_link); + g_free(file_name); + } + /* + * if map failed with MAP_SHARED_VALIDATE | MAP_SYNC, + * we will remove these flags to handle compatibility. + */ + ptr = mmap(guardptr + offset, size, PROT_READ | PROT_WRITE, + flags, fd, 0); + } if (ptr == MAP_FAILED) { munmap(guardptr, total);