| Message ID | 20230825135431.1317785-1-hao.xu@linux.dev (mailing list archive) |
|---|---|
| Headers | show |
| Series | io_uring getdents | expand |
On Fri, Aug 25, 2023 at 09:54:02PM +0800, Hao Xu wrote: > From: Hao Xu <howeyxu@tencent.com> > > This series introduce getdents64 to io_uring, the code logic is similar > with the snychronized version's. It first try nowait issue, and offload > it to io-wq threads if the first try fails. NAK on the entire series until Jens actually writes down what NOWAIT does, so that we can check that the *existing* nowait code branches actually behave how he says it should. https://lore.kernel.org/all/e2d8e5f1-f794-38eb-cecf-ed30c571206b@kernel.dk/ --D > > Patch1 and Patch2 are some preparation > Patch3 supports nowait for xfs getdents code > Patch4-11 are vfs change, include adding helpers and trylock for locks > Patch12-29 supports nowait for involved xfs journal stuff > note, Patch24 and 27 are actually two questions, might be removed later. > an xfs test may come later. > > Tests I've done: > a liburing test case for functional test: > https://github.com/HowHsu/liburing/commit/39dc9a8e19c06a8cebf8c2301b85320eb45c061e?diff=unified > > xfstests: > test/generic: 1 fails and 171 not run > test/xfs: 72 fails and 156 not run > run the code before without this patchset, same result. > I'll try to make the environment more right to run more tests here. > > > Tested it with a liburing performance test: > https://github.com/HowHsu/liburing/blob/getdents/test/getdents2.c > > The test is controlled by the below script[2] which runs getdents2.t 100 > times and calulate the avg. > The result show that io_uring version is about 2.6% faster: > > note: > [1] the number of getdents call/request in io_uring and normal sync version > are made sure to be same beforehand. > > [2] run_getdents.py > > ```python3 > > import subprocess > > N = 100 > sum = 0.0 > args = ["/data/home/howeyxu/tmpdir", "sync"] > > for i in range(N): > output = subprocess.check_output(["./liburing/test/getdents2.t"] + args) > sum += float(output) > > average = sum / N > print("Average of sync:", average) > > sum = 0.0 > args = ["/data/home/howeyxu/tmpdir", "iouring"] > > for i in range(N): > output = subprocess.check_output(["./liburing/test/getdents2.t"] + args) > sum += float(output) > > average = sum / N > print("Average of iouring:", average) > > ``` > > v4->v5: > - move atime update to the beginning of getdents operation > - trylock for i_rwsem > - nowait semantics for involved xfs journal stuff > > v3->v4: > - add Dave's xfs nowait code and fix a deadlock problem, with some code > style tweak. > - disable fixed file to avoid a race problem for now > - add a test program. > > v2->v3: > - removed the kernfs patches > - add f_pos_lock logic > - remove the "reduce last EOF getdents try" optimization since > Dominique reports that doesn't make difference > - remove the rewind logic, I think the right way is to introduce lseek > to io_uring not to patch this logic to getdents. > - add Singed-off-by of Stefan Roesch for patch 1 since checkpatch > complained that Co-developed-by someone should be accompanied with > Signed-off-by same person, I can remove them if Stefan thinks that's > not proper. > > > Dominique Martinet (1): > fs: split off vfs_getdents function of getdents64 syscall > > Hao Xu (28): > xfs: rename XBF_TRYLOCK to XBF_NOWAIT > xfs: add NOWAIT semantics for readdir > vfs: add nowait flag for struct dir_context > vfs: add a vfs helper for io_uring file pos lock > vfs: add file_pos_unlock() for io_uring usage > vfs: add a nowait parameter for touch_atime() > vfs: add nowait parameter for file_accessed() > vfs: move file_accessed() to the beginning of iterate_dir() > vfs: add S_NOWAIT for nowait time update > vfs: trylock inode->i_rwsem in iterate_dir() to support nowait > xfs: enforce GFP_NOIO implicitly during nowait time update > xfs: make xfs_trans_alloc() support nowait semantics > xfs: support nowait for xfs_log_reserve() > xfs: don't wait for free space in xlog_grant_head_check() in nowait > case > xfs: add nowait parameter for xfs_inode_item_init() > xfs: make xfs_trans_ijoin() error out -EAGAIN > xfs: set XBF_NOWAIT for xfs_buf_read_map if necessary > xfs: support nowait memory allocation in _xfs_buf_alloc() > xfs: distinguish error type of memory allocation failure for nowait > case > xfs: return -EAGAIN when bulk memory allocation fails in nowait case > xfs: comment page allocation for nowait case in xfs_buf_find_insert() > xfs: don't print warn info for -EAGAIN error in xfs_buf_get_map() > xfs: support nowait for xfs_buf_read_map() > xfs: support nowait for xfs_buf_item_init() > xfs: return -EAGAIN when nowait meets sync in transaction commit > xfs: add a comment for xlog_kvmalloc() > xfs: support nowait semantics for xc_ctx_lock in xlog_cil_commit() > io_uring: add support for getdents > > arch/s390/hypfs/inode.c | 2 +- > block/fops.c | 2 +- > fs/btrfs/file.c | 2 +- > fs/btrfs/inode.c | 2 +- > fs/cachefiles/namei.c | 2 +- > fs/coda/dir.c | 4 +-- > fs/ecryptfs/file.c | 4 +-- > fs/ext2/file.c | 4 +-- > fs/ext4/file.c | 6 ++-- > fs/f2fs/file.c | 4 +-- > fs/file.c | 13 +++++++ > fs/fuse/dax.c | 2 +- > fs/fuse/file.c | 4 +-- > fs/gfs2/file.c | 2 +- > fs/hugetlbfs/inode.c | 2 +- > fs/inode.c | 10 +++--- > fs/internal.h | 8 +++++ > fs/namei.c | 4 +-- > fs/nfsd/vfs.c | 2 +- > fs/nilfs2/file.c | 2 +- > fs/orangefs/file.c | 2 +- > fs/orangefs/inode.c | 2 +- > fs/overlayfs/file.c | 2 +- > fs/overlayfs/inode.c | 2 +- > fs/pipe.c | 2 +- > fs/ramfs/file-nommu.c | 2 +- > fs/readdir.c | 61 +++++++++++++++++++++++++-------- > fs/smb/client/cifsfs.c | 2 +- > fs/splice.c | 2 +- > fs/stat.c | 2 +- > fs/ubifs/file.c | 2 +- > fs/udf/file.c | 2 +- > fs/xfs/libxfs/xfs_alloc.c | 2 +- > fs/xfs/libxfs/xfs_attr_remote.c | 2 +- > fs/xfs/libxfs/xfs_btree.c | 2 +- > fs/xfs/libxfs/xfs_da_btree.c | 16 +++++++++ > fs/xfs/libxfs/xfs_da_btree.h | 1 + > fs/xfs/libxfs/xfs_dir2_block.c | 7 ++-- > fs/xfs/libxfs/xfs_dir2_priv.h | 2 +- > fs/xfs/libxfs/xfs_shared.h | 2 ++ > fs/xfs/libxfs/xfs_trans_inode.c | 12 +++++-- > fs/xfs/scrub/dir.c | 2 +- > fs/xfs/scrub/readdir.c | 2 +- > fs/xfs/scrub/repair.c | 2 +- > fs/xfs/xfs_buf.c | 43 +++++++++++++++++------ > fs/xfs/xfs_buf.h | 4 +-- > fs/xfs/xfs_buf_item.c | 9 +++-- > fs/xfs/xfs_buf_item.h | 2 +- > fs/xfs/xfs_buf_item_recover.c | 2 +- > fs/xfs/xfs_dir2_readdir.c | 49 ++++++++++++++++++++------ > fs/xfs/xfs_dquot.c | 2 +- > fs/xfs/xfs_file.c | 6 ++-- > fs/xfs/xfs_inode.c | 27 +++++++++++++++ > fs/xfs/xfs_inode.h | 17 +++++---- > fs/xfs/xfs_inode_item.c | 12 ++++--- > fs/xfs/xfs_inode_item.h | 3 +- > fs/xfs/xfs_iops.c | 31 ++++++++++++++--- > fs/xfs/xfs_log.c | 33 ++++++++++++------ > fs/xfs/xfs_log.h | 5 +-- > fs/xfs/xfs_log_cil.c | 17 +++++++-- > fs/xfs/xfs_log_priv.h | 4 +-- > fs/xfs/xfs_trans.c | 44 ++++++++++++++++++++---- > fs/xfs/xfs_trans.h | 2 +- > fs/xfs/xfs_trans_buf.c | 18 ++++++++-- > fs/zonefs/file.c | 4 +-- > include/linux/file.h | 7 ++++ > include/linux/fs.h | 16 +++++++-- > include/uapi/linux/io_uring.h | 1 + > io_uring/fs.c | 53 ++++++++++++++++++++++++++++ > io_uring/fs.h | 3 ++ > io_uring/opdef.c | 8 +++++ > kernel/bpf/inode.c | 4 +-- > mm/filemap.c | 8 ++--- > mm/shmem.c | 6 ++-- > net/unix/af_unix.c | 4 +-- > 75 files changed, 499 insertions(+), 161 deletions(-) > > -- > 2.25.1 >
On Fri, Aug 25, 2023 at 09:54:02PM +0800, Hao Xu wrote: > From: Hao Xu <howeyxu@tencent.com> > > This series introduce getdents64 to io_uring, the code logic is similar > with the snychronized version's. It first try nowait issue, and offload > it to io-wq threads if the first try fails. > > Patch1 and Patch2 are some preparation > Patch3 supports nowait for xfs getdents code > Patch4-11 are vfs change, include adding helpers and trylock for locks > Patch12-29 supports nowait for involved xfs journal stuff > note, Patch24 and 27 are actually two questions, might be removed later. > an xfs test may come later. You need to drop all the XFS journal stuff. It's fundamentally broken as it stands, and we cannot support non-blocking transactional changes without first putting a massive investment in transaction and intent chain rollback to allow correctly undoing partially complete modifications. Regardless, non-blocking transactions are completely unnecessary for a non-blocking readdir implementation. readdir should only be touching atime, and with relatime it should only occur once every 24 hours per inode. If that's a problem, then we have noatime mount options. Hence I just don't see any point in worrying about having a timestamp update block occasionally... I also don't really don't see why you need to fiddle with xfs buffer cache semantics - it already has the functionality "nowait" buffer reads require (i.e. XBF_INCORE|XBF_TRYLOCK). However, the readahead IO that the xfs readdir code issues cannot use your defined NOWAIT semantics - it must be able to allocate memory and issue IO. Readahead already avoids blocking on memory allocation and blocking on IO via the XBF_READ_AHEAD flag. This sets __GFP_NORETRY for buffer allocation and REQ_RAHEAD for IO. Hence readahead only needs the existing XBF_TRYLOCK flag to be set to be compatible with the required NOWAIT semantics.... As for the NOIO memory allocation restrictions io_uring requires, that should be enforced at the io_uring layer before calling into the VFS using memalloc_noio_save/restore. At that point no memory allocation will trigger IO and none of the code running under NOWAIT conditions even needs to be aware that io_uring has a GFP_NOIO restriction on memory allocation.... Please go back to the simple "do non-blocking buffer IO" implementation we started with and don't try to solve every little blocking problem that might exist in the VFS and filesystems... -Dave
From: Hao Xu <howeyxu@tencent.com> This series introduce getdents64 to io_uring, the code logic is similar with the snychronized version's. It first try nowait issue, and offload it to io-wq threads if the first try fails. Patch1 and Patch2 are some preparation Patch3 supports nowait for xfs getdents code Patch4-11 are vfs change, include adding helpers and trylock for locks Patch12-29 supports nowait for involved xfs journal stuff note, Patch24 and 27 are actually two questions, might be removed later. an xfs test may come later. Tests I've done: a liburing test case for functional test: https://github.com/HowHsu/liburing/commit/39dc9a8e19c06a8cebf8c2301b85320eb45c061e?diff=unified xfstests: test/generic: 1 fails and 171 not run test/xfs: 72 fails and 156 not run run the code before without this patchset, same result. I'll try to make the environment more right to run more tests here. Tested it with a liburing performance test: https://github.com/HowHsu/liburing/blob/getdents/test/getdents2.c The test is controlled by the below script[2] which runs getdents2.t 100 times and calulate the avg. The result show that io_uring version is about 2.6% faster: note: [1] the number of getdents call/request in io_uring and normal sync version are made sure to be same beforehand. [2] run_getdents.py ```python3 import subprocess N = 100 sum = 0.0 args = ["/data/home/howeyxu/tmpdir", "sync"] for i in range(N): output = subprocess.check_output(["./liburing/test/getdents2.t"] + args) sum += float(output) average = sum / N print("Average of sync:", average) sum = 0.0 args = ["/data/home/howeyxu/tmpdir", "iouring"] for i in range(N): output = subprocess.check_output(["./liburing/test/getdents2.t"] + args) sum += float(output) average = sum / N print("Average of iouring:", average) ``` v4->v5: - move atime update to the beginning of getdents operation - trylock for i_rwsem - nowait semantics for involved xfs journal stuff v3->v4: - add Dave's xfs nowait code and fix a deadlock problem, with some code style tweak. - disable fixed file to avoid a race problem for now - add a test program. v2->v3: - removed the kernfs patches - add f_pos_lock logic - remove the "reduce last EOF getdents try" optimization since Dominique reports that doesn't make difference - remove the rewind logic, I think the right way is to introduce lseek to io_uring not to patch this logic to getdents. - add Singed-off-by of Stefan Roesch for patch 1 since checkpatch complained that Co-developed-by someone should be accompanied with Signed-off-by same person, I can remove them if Stefan thinks that's not proper. Dominique Martinet (1): fs: split off vfs_getdents function of getdents64 syscall Hao Xu (28): xfs: rename XBF_TRYLOCK to XBF_NOWAIT xfs: add NOWAIT semantics for readdir vfs: add nowait flag for struct dir_context vfs: add a vfs helper for io_uring file pos lock vfs: add file_pos_unlock() for io_uring usage vfs: add a nowait parameter for touch_atime() vfs: add nowait parameter for file_accessed() vfs: move file_accessed() to the beginning of iterate_dir() vfs: add S_NOWAIT for nowait time update vfs: trylock inode->i_rwsem in iterate_dir() to support nowait xfs: enforce GFP_NOIO implicitly during nowait time update xfs: make xfs_trans_alloc() support nowait semantics xfs: support nowait for xfs_log_reserve() xfs: don't wait for free space in xlog_grant_head_check() in nowait case xfs: add nowait parameter for xfs_inode_item_init() xfs: make xfs_trans_ijoin() error out -EAGAIN xfs: set XBF_NOWAIT for xfs_buf_read_map if necessary xfs: support nowait memory allocation in _xfs_buf_alloc() xfs: distinguish error type of memory allocation failure for nowait case xfs: return -EAGAIN when bulk memory allocation fails in nowait case xfs: comment page allocation for nowait case in xfs_buf_find_insert() xfs: don't print warn info for -EAGAIN error in xfs_buf_get_map() xfs: support nowait for xfs_buf_read_map() xfs: support nowait for xfs_buf_item_init() xfs: return -EAGAIN when nowait meets sync in transaction commit xfs: add a comment for xlog_kvmalloc() xfs: support nowait semantics for xc_ctx_lock in xlog_cil_commit() io_uring: add support for getdents arch/s390/hypfs/inode.c | 2 +- block/fops.c | 2 +- fs/btrfs/file.c | 2 +- fs/btrfs/inode.c | 2 +- fs/cachefiles/namei.c | 2 +- fs/coda/dir.c | 4 +-- fs/ecryptfs/file.c | 4 +-- fs/ext2/file.c | 4 +-- fs/ext4/file.c | 6 ++-- fs/f2fs/file.c | 4 +-- fs/file.c | 13 +++++++ fs/fuse/dax.c | 2 +- fs/fuse/file.c | 4 +-- fs/gfs2/file.c | 2 +- fs/hugetlbfs/inode.c | 2 +- fs/inode.c | 10 +++--- fs/internal.h | 8 +++++ fs/namei.c | 4 +-- fs/nfsd/vfs.c | 2 +- fs/nilfs2/file.c | 2 +- fs/orangefs/file.c | 2 +- fs/orangefs/inode.c | 2 +- fs/overlayfs/file.c | 2 +- fs/overlayfs/inode.c | 2 +- fs/pipe.c | 2 +- fs/ramfs/file-nommu.c | 2 +- fs/readdir.c | 61 +++++++++++++++++++++++++-------- fs/smb/client/cifsfs.c | 2 +- fs/splice.c | 2 +- fs/stat.c | 2 +- fs/ubifs/file.c | 2 +- fs/udf/file.c | 2 +- fs/xfs/libxfs/xfs_alloc.c | 2 +- fs/xfs/libxfs/xfs_attr_remote.c | 2 +- fs/xfs/libxfs/xfs_btree.c | 2 +- fs/xfs/libxfs/xfs_da_btree.c | 16 +++++++++ fs/xfs/libxfs/xfs_da_btree.h | 1 + fs/xfs/libxfs/xfs_dir2_block.c | 7 ++-- fs/xfs/libxfs/xfs_dir2_priv.h | 2 +- fs/xfs/libxfs/xfs_shared.h | 2 ++ fs/xfs/libxfs/xfs_trans_inode.c | 12 +++++-- fs/xfs/scrub/dir.c | 2 +- fs/xfs/scrub/readdir.c | 2 +- fs/xfs/scrub/repair.c | 2 +- fs/xfs/xfs_buf.c | 43 +++++++++++++++++------ fs/xfs/xfs_buf.h | 4 +-- fs/xfs/xfs_buf_item.c | 9 +++-- fs/xfs/xfs_buf_item.h | 2 +- fs/xfs/xfs_buf_item_recover.c | 2 +- fs/xfs/xfs_dir2_readdir.c | 49 ++++++++++++++++++++------ fs/xfs/xfs_dquot.c | 2 +- fs/xfs/xfs_file.c | 6 ++-- fs/xfs/xfs_inode.c | 27 +++++++++++++++ fs/xfs/xfs_inode.h | 17 +++++---- fs/xfs/xfs_inode_item.c | 12 ++++--- fs/xfs/xfs_inode_item.h | 3 +- fs/xfs/xfs_iops.c | 31 ++++++++++++++--- fs/xfs/xfs_log.c | 33 ++++++++++++------ fs/xfs/xfs_log.h | 5 +-- fs/xfs/xfs_log_cil.c | 17 +++++++-- fs/xfs/xfs_log_priv.h | 4 +-- fs/xfs/xfs_trans.c | 44 ++++++++++++++++++++---- fs/xfs/xfs_trans.h | 2 +- fs/xfs/xfs_trans_buf.c | 18 ++++++++-- fs/zonefs/file.c | 4 +-- include/linux/file.h | 7 ++++ include/linux/fs.h | 16 +++++++-- include/uapi/linux/io_uring.h | 1 + io_uring/fs.c | 53 ++++++++++++++++++++++++++++ io_uring/fs.h | 3 ++ io_uring/opdef.c | 8 +++++ kernel/bpf/inode.c | 4 +-- mm/filemap.c | 8 ++--- mm/shmem.c | 6 ++-- net/unix/af_unix.c | 4 +-- 75 files changed, 499 insertions(+), 161 deletions(-)