Return-Path: Received: from mx144.netapp.com ([216.240.21.25]:49777 "EHLO mx144.netapp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754009AbbIKUa2 (ORCPT ); Fri, 11 Sep 2015 16:30:28 -0400 From: Anna Schumaker To: , , , , , , , , , , Subject: [PATCH v2 0/9] VFS: In-kernel copy system call Date: Fri, 11 Sep 2015 16:30:13 -0400 Message-ID: <1442003423-6884-1-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. Changes in v2: - Update against the most recent Linus kernel - Fix conflicts due to new system calls - Remove requirement that inode_in == inode_out - Drop patch to add mountpoint checking to btrfs - btrfs already did this check - Rename COPY_REFLINK -> COPY_FR_REFLINK - Add COPY_FR_COPY flag - Expand flags == 0 to (COPY_FR_COPY | COPY_FR_REFLINK) - Remove checking for invalid flags - Create a new function for handling pagecache copies - Move rw_verify_area() checks into the new pagecache-copy function - Use the return value from rw_verify_area() to set amount of data to copy - Update man page I tested the COPY_FR_COPY flag by using /dev/urandom to generate files of varying sizes and copying them. I compared the output from `time` against that of `cp` to see if there is any noticable difference. I think there have been some libvirt changes since my first set of trials, because this time around cpu usage was down significantly. This time around, VFS copy was slightly faster than /usr/bin/cp in all cases. Values in the tables below are averages across multiple trials. /usr/bin/cp | 512 | 1024 | 1536 | 2048 | 2560 | 3072 | 5120 -------------|--------|--------|--------|--------|--------|--------|-------- user | 0.00s | 0.01s | 0.01s | 0.01s | 0.01s | 0.01s | 0.02s system | 0.68s | 0.48s | 0.74s | 0.99s | 1.25s | 1.50s | 2.51s cpu | 34% | 14% | 14% | 15% | 14% | 14% | 15% total | 1.993 | 3.314 | 4.994 | 6.599 | 8.627 | 10.079 | 16.852 VFS copy | 512 | 1024 | 1536 | 2048 | 2560 | 3072 | 5120 -------------|--------|--------|--------|--------|--------|--------|-------- user | 0.00s | 0.00s | 0.00s | 0.00s | 0.00s | 0.00s | 0.00s system | 0.65s | 0.46s | 0.70s | 0.93s | 1.18s | 1.41s | 2.37s cpu | 35% | 14% | 15% | 14% | 14% | 14% | 14% total | 1.870 | 3.084 | 4.613 | 6.206 | 7.884 | 9.372 | 15.904 Questions? Comments? Thoughts? Anna Anna Schumaker (6): vfs: Copy should check len after file open mode vfs: Copy shouldn't forbid ranges inside the same file vfs: Copy should use file_out rather than file_in vfs: Remove copy_file_range mountpoint checks vfs: copy_file_range() can do a pagecache copy with splice btrfs: btrfs_copy_file_range() only supports reflinks 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 | 7 ++ kernel/sys_ni.c | 1 + 12 files changed, 215 insertions(+), 40 deletions(-) create mode 100644 include/linux/copy.h create mode 100644 include/uapi/linux/copy.h -- 2.5.1