From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:39221) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1geZ1v-0000m2-FG for qemu-devel@nongnu.org; Wed, 02 Jan 2019 00:25:24 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1geZ1s-0003lc-Bo for qemu-devel@nongnu.org; Wed, 02 Jan 2019 00:25:23 -0500 Received: from mga14.intel.com ([192.55.52.115]:34686) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1geZ1q-0003h4-Qh for qemu-devel@nongnu.org; Wed, 02 Jan 2019 00:25:19 -0500 From: Zhang Yi Date: Wed, 2 Jan 2019 13:25:21 +0800 Message-Id: Subject: [Qemu-devel] [PATCH V8 0/5] support MAP_SYNC for memory-backend-file List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: xiaoguangrong.eric@gmail.com, stefanha@redhat.com, pbonzini@redhat.com, pagupta@redhat.com, yu.c.zhang@linux.intel.com, mst@redhat.com Cc: qemu-devel@nongnu.org, imammedo@redhat.com, dan.j.williams@intel.com, ehabkost@redhat.com, Zhang Yi 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. A new on/off option 'sync' is added to memory-backend-file: - on: try to pass MAP_SYNC to mmap(2); if MAP_SYNC is not supported or 'share=off' or 'pmem=off', QEMU will not pass this flag to mmap(2) - off: (default) never pass MAP_SYNC to mmap(2) 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 (5): numa: Fixed the memory leak of numa error message util/mmap-alloc: switch qemu_ram_mmap() to 'flags' parameter util/mmap-alloc: support MAP_SYNC in qemu_ram_mmap() hostmem: add more information in error messages hostmem-file: add 'sync' option backends/hostmem-file.c | 34 ++++++++++++++++++++++++++++++++-- backends/hostmem.c | 8 +++++--- docs/nvdimm.txt | 23 ++++++++++++++++++++++- exec.c | 9 +++++---- include/exec/memory.h | 26 ++++++++++++++++++++------ include/exec/ram_addr.h | 1 + include/qemu/mmap-alloc.h | 20 +++++++++++++++++++- include/qemu/osdep.h | 16 ++++++++++++++++ numa.c | 1 + qemu-options.hx | 19 ++++++++++++++++++- util/mmap-alloc.c | 20 ++++++++++++++++---- util/oslib-posix.c | 9 ++++++++- 12 files changed, 163 insertions(+), 23 deletions(-) -- 2.7.4