From nobody Fri Nov 7 04:02:13 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=linux.intel.com Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1546407003787223.73070510749096; Tue, 1 Jan 2019 21:30:03 -0800 (PST) Received: from localhost ([127.0.0.1]:42049 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1geZ6Q-0005NF-C3 for importer@patchew.org; Wed, 02 Jan 2019 00:30:02 -0500 Received: from eggs.gnu.org ([208.118.235.92]:39460) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1geZ2k-0001gE-5n for qemu-devel@nongnu.org; Wed, 02 Jan 2019 00:26:15 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1geZ2h-0006a7-2L for qemu-devel@nongnu.org; Wed, 02 Jan 2019 00:26:14 -0500 Received: from mga17.intel.com ([192.55.52.151]:11102) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1geZ2g-0006Zh-Qy for qemu-devel@nongnu.org; Wed, 02 Jan 2019 00:26:11 -0500 Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga107.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 01 Jan 2019 21:26:09 -0800 Received: from linux.intel.com ([10.54.29.200]) by fmsmga001.fm.intel.com with ESMTP; 01 Jan 2019 21:26:09 -0800 Received: from dazhang1-ssd.sh.intel.com (unknown [10.239.48.128]) by linux.intel.com (Postfix) with ESMTP id 7D9D3580310; Tue, 1 Jan 2019 21:26:07 -0800 (PST) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,429,1539673200"; d="scan'208";a="134604940" From: Zhang Yi To: xiaoguangrong.eric@gmail.com, stefanha@redhat.com, pbonzini@redhat.com, pagupta@redhat.com, yu.c.zhang@linux.intel.com, mst@redhat.com Date: Wed, 2 Jan 2019 13:26:15 +0800 Message-Id: <0b17cd9e914372c4790296b2cc21d6dd6e6d5466.1546399191.git.yi.z.zhang@linux.intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: References: X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 192.55.52.151 Subject: [Qemu-devel] [PATCH V8 3/5] 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: imammedo@redhat.com, dan.j.williams@intel.com, Zhang Yi , qemu-devel@nongnu.org, ehabkost@redhat.com Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" 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). Signed-off-by: Haozhong Zhang Signed-off-by: Zhang Yi --- include/qemu/osdep.h | 16 ++++++++++++++++ util/mmap-alloc.c | 12 +++++++++++- 2 files changed, 27 insertions(+), 1 deletion(-) diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h index 3bf48bc..bb1eba1 100644 --- a/include/qemu/osdep.h +++ b/include/qemu/osdep.h @@ -410,6 +410,22 @@ void qemu_anon_ram_free(void *ptr, size_t size); # define QEMU_VMALLOC_ALIGN getpagesize() #endif =20 +/* + * MAP_SHARED_VALIDATE and MAP_SYNC are introduced in Linux kernel + * 4.15, so they may not be defined when compiling on older kernels. + */ +#ifdef CONFIG_LINUX + +#include + +#ifndef MAP_SYNC +#define MAP_SYNC 0x0 +#endif + +#else /* !CONFIG_LINUX */ +#define MAP_SYNC 0x0 +#endif /* CONFIG_LINUX */ + #ifdef CONFIG_POSIX struct qemu_signalfd_siginfo { uint32_t ssi_signo; /* Signal number */ diff --git a/util/mmap-alloc.c b/util/mmap-alloc.c index 8f0a740..a9d5e56 100644 --- a/util/mmap-alloc.c +++ b/util/mmap-alloc.c @@ -99,6 +99,8 @@ void *qemu_ram_mmap(int fd, size_t size, size_t align, ui= nt32_t flags) void *ptr =3D mmap(0, total, PROT_NONE, MAP_ANONYMOUS | MAP_PRIVATE, -= 1, 0); #endif bool shared =3D flags & RAM_SHARED; + bool is_pmem =3D flags & RAM_PMEM; + int mmap_xflags =3D 0; size_t offset; void *ptr1; =20 @@ -109,13 +111,21 @@ void *qemu_ram_mmap(int fd, size_t size, size_t align= , uint32_t flags) assert(is_power_of_2(align)); /* Always align to host page size */ assert(align >=3D getpagesize()); + if (shared && is_pmem) { + mmap_xflags |=3D MAP_SYNC; + } =20 offset =3D QEMU_ALIGN_UP((uintptr_t)ptr, align) - (uintptr_t)ptr; + retry_mmap_fd: ptr1 =3D mmap(ptr + offset, size, PROT_READ | PROT_WRITE, MAP_FIXED | (fd =3D=3D -1 ? MAP_ANONYMOUS : 0) | - (shared ? MAP_SHARED : MAP_PRIVATE), + (shared ? MAP_SHARED : MAP_PRIVATE) | mmap_xflags, fd, 0); + if ((ptr1 =3D=3D MAP_FAILED) && (mmap_xflags & MAP_SYNC)) { + mmap_xflags &=3D ~MAP_SYNC; + goto retry_mmap_fd; + } if (ptr1 =3D=3D MAP_FAILED) { munmap(ptr, total); return MAP_FAILED; --=20 2.7.4