From patchwork Tue Jan 29 14:49:09 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Zhang, Yi" X-Patchwork-Id: 10785511 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 0FA7813B4 for ; Tue, 29 Jan 2019 06:22:11 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id F1F8B2B118 for ; Tue, 29 Jan 2019 06:22:10 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id E49CD2B4AB; Tue, 29 Jan 2019 06:22:10 +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=-1.0 required=2.0 tests=BAYES_00,DATE_IN_FUTURE_06_12, MAILING_LIST_MULTI 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 810512B118 for ; Tue, 29 Jan 2019 06:22:10 +0000 (UTC) Received: from localhost ([127.0.0.1]:43974 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1goMmf-0005UL-Rd for patchwork-qemu-devel@patchwork.kernel.org; Tue, 29 Jan 2019 01:22:09 -0500 Received: from eggs.gnu.org ([209.51.188.92]:35611) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1goMjP-0003C9-79 for qemu-devel@nongnu.org; Tue, 29 Jan 2019 01:18:50 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1goMjO-0006Sb-Cb for qemu-devel@nongnu.org; Tue, 29 Jan 2019 01:18:47 -0500 Received: from mga12.intel.com ([192.55.52.136]:31984) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1goMjO-0006Na-2C for qemu-devel@nongnu.org; Tue, 29 Jan 2019 01:18:46 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga106.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 28 Jan 2019 22:18:31 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,536,1539673200"; d="scan'208";a="139657669" Received: from dazhang1-ssd.sh.intel.com (HELO localhost) ([10.239.48.91]) by fmsmga004.fm.intel.com with ESMTP; 28 Jan 2019 22:18:29 -0800 From: "Zhang, Yi" To: xiaoguangrong.eric@gmail.com, stefanha@redhat.com, pbonzini@redhat.com, pagupta@redhat.com, yu.c.zhang@linux.intel.com, richardw.yang@linux.intel.com, mst@redhat.com, ehabkost@redhat.com Date: Tue, 29 Jan 2019 22:49:09 +0800 Message-Id: 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: 192.55.52.136 Subject: [Qemu-devel] [PATCH v11 2/3] 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, qemu-devel@nongnu.org, Zhang Yi 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 --- include/qemu/osdep.h | 21 +++++++++++++++++++++ util/mmap-alloc.c | 28 +++++++++++++++++++++++++++- 2 files changed, 48 insertions(+), 1 deletion(-) diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h index 457d24e..96209bb 100644 --- a/include/qemu/osdep.h +++ b/include/qemu/osdep.h @@ -419,6 +419,27 @@ void qemu_anon_ram_free(void *ptr, size_t size); # define QEMU_VMALLOC_ALIGN getpagesize() #endif +/* + * 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 0x80000 +#endif + +#ifndef MAP_SHARED_VALIDATE +#define MAP_SHARED_VALIDATE 0x03 +#endif + +#else /* !CONFIG_LINUX */ +#define MAP_SYNC 0x0 +#define MAP_SHARED_VALIDATE 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 97bbeed..2c86ad2 100644 --- a/util/mmap-alloc.c +++ b/util/mmap-alloc.c @@ -101,6 +101,7 @@ void *qemu_ram_mmap(int fd, #else void *ptr = mmap(0, total, PROT_NONE, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0); #endif + int mmap_xflags = 0; size_t offset; void *ptr1; @@ -111,13 +112,38 @@ void *qemu_ram_mmap(int fd, assert(is_power_of_2(align)); /* Always align to host page size */ assert(align >= getpagesize()); + if (shared && is_pmem) { + mmap_xflags = MAP_SYNC | MAP_SHARED_VALIDATE; + } offset = QEMU_ALIGN_UP((uintptr_t)ptr, align) - (uintptr_t)ptr; +retry_mmap: ptr1 = mmap(ptr + offset, size, PROT_READ | PROT_WRITE, MAP_FIXED | (fd == -1 ? MAP_ANONYMOUS : 0) | - (shared ? MAP_SHARED : MAP_PRIVATE), + (shared ? MAP_SHARED : MAP_PRIVATE) | mmap_xflags, fd, 0); + + /* if map failed with MAP_SHARED_VALIDATE | MAP_SYNC, + * we try with MAP_SHARED_VALIDATE without MAP_SYNC + */ + if (ptr1 == MAP_FAILED && + mmap_xflags == (MAP_SYNC | MAP_SHARED_VALIDATE)) { + if (errno == ENOTSUP) { + perror("failed to validate with mapping flags"); + } + mmap_xflags = MAP_SHARED_VALIDATE; + goto retry_mmap; + } + /* MAP_SHARED_VALIDATE flag is available since Linux 4.15 + * Test only with MAP_SHARED_VALIDATE flag for compatibility. + * Then ignore the MAP_SHARED_VALIDATE flag and retry again + */ + if (mmap_xflags == MAP_SHARED_VALIDATE && + ptr1 == MAP_FAILED) { + mmap_xflags &= ~MAP_SHARED_VALIDATE; + goto retry_mmap; + } if (ptr1 == MAP_FAILED) { munmap(ptr, total); return MAP_FAILED;