Return-Path: Received: from mx143.netapp.com ([216.240.21.24]:14075 "EHLO mx143.netapp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760089AbbIDURI (ORCPT ); Fri, 4 Sep 2015 16:17:08 -0400 From: Anna Schumaker To: , , , , , , , , , , Subject: [PATCH v1 0/8] VFS: In-kernel copy system call Date: Fri, 4 Sep 2015 16:16:54 -0400 Message-ID: <1441397823-1203-1-git-send-email-Anna.Schumaker@Netapp.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-nfs-owner@vger.kernel.org List-ID: Copy system calls came up during Plumbers a couple of weeks ago, because several filesystems (including NFS and XFS) are currently working on copy acceleration implementations. We haven't heard from Zach Brown in a while, so I volunteered to push his patches upstream so individual filesystems don't need to keep writing their own ioctls. The first three patches are a simple reposting of Zach's patches from several months ago, with one minor error code fix. The remaining patches add in a fallback mechanism when filesystems don't provide a copy function. This is especially useful when doing a server-side copy on NFS (using the new COPY operation in NFS v4.2). This fallback can be disabled by passing the flag COPY_REFLINK to the system call. The last patch is a man page patch documenting this new system call, including an example program. I tested the fallback option by using /dev/urandom to generate files of varying sizes and copying them. I compared the time to copy against that of `cp` just to see if there is a noticable difference. I found that runtimes are roughly the same, but in-kernel copy tends to use less of the cpu. Values in the tables below are averages across multiple trials. /usr/bin/cp | 512 MB | 1024 MB | 1536 MB | 2048 MB -------------|-----------|-----------|-----------|----------- user | 0.00s | 0.00s | 0.00s | 0.00s system | 0.32s | 0.52s | 1.04s | 1.04s cpu | 73% | 69% | 62% | 62% total | 0.446 | 0.757 | 1.197 | 1.667 VFS copy | 512 MB | 1024 MB | 1536 MB | 2048 MB -------------|-----------|-----------|-----------|----------- user | 0.00s | 0.00s | 0.00s | 0.00s system | 0.33s | 0.49s | 0.76s | 0.99s cpu | 77% | 62% | 60% | 59% total | 0.422 | 0.777 | 1.267 | 1.655 Questions? Comments? Thoughts? Anna Anna Schumaker (5): btrfs: Add mountpoint checking during btrfs_copy_file_range vfs: Remove copy_file_range mountpoint checks vfs: Copy should check len after file open mode vfs: Copy should use file_out rather than file_in vfs: Fall back on splice if no copy function defined Zach Brown (3): vfs: add copy_file_range syscall and vfs helper x86: add sys_copy_file_range to syscall tables btrfs: add .copy_file_range file operation arch/x86/entry/syscalls/syscall_32.tbl | 1 + arch/x86/entry/syscalls/syscall_64.tbl | 1 + fs/btrfs/ctree.h | 3 + fs/btrfs/file.c | 1 + fs/btrfs/ioctl.c | 95 ++++++++++++++---------- fs/read_write.c | 132 +++++++++++++++++++++++++++++++++ include/linux/copy.h | 6 ++ include/linux/fs.h | 3 + include/uapi/asm-generic/unistd.h | 4 +- include/uapi/linux/Kbuild | 1 + include/uapi/linux/copy.h | 6 ++ kernel/sys_ni.c | 1 + 12 files changed, 214 insertions(+), 40 deletions(-) create mode 100644 include/linux/copy.h create mode 100644 include/uapi/linux/copy.h -- 2.5.1