korg/linux
0
0
Fork 0
mirror of https://mirrors.bfsu.edu.cn/git/linux.git synced 2025-01-12 08:45:11 +08:00
Code Issues Packages Projects Releases Wiki Activity
f26c923860
linux/fs/btrfs
History
Qu Wenruo f26c923860 btrfs: remove reada infrastructure 
Currently there is only one user for btrfs metadata readahead, and
that's scrub.

But even for the single user, it's not providing the correct
functionality it needs, as scrub needs reada for commit root, which
current readahead can't provide. (Although it's pretty easy to add such
feature).

Despite this, there are some extra problems related to metadata
readahead:

- Duplicated feature with btrfs_path::reada

- Partly duplicated feature of btrfs_fs_info::buffer_radix
  Btrfs already caches its metadata in buffer_radix, while readahead
  tries to read the tree block no matter if it's already cached.

- Poor layer separation
  Metadata readahead works kinda at device level.
  This is definitely not the correct layer it should be, since metadata
  is at btrfs logical address space, it should not bother device at all.

  This brings extra chance for bugs to sneak in, while brings
  unnecessary complexity.

- Dead code
  In the very beginning of scrub.c we have #undef DEBUG, rendering all
  the debug related code useless and unable to test.

Thus here I purpose to remove the metadata readahead mechanism
completely.

[BENCHMARK]
There is a full benchmark for the scrub performance difference using the
old btrfs_reada_add() and btrfs_path::reada.

For the worst case (no dirty metadata, slow HDD), there could be a 5%
performance drop for scrub.
For other cases (even SATA SSD), there is no distinguishable performance
difference.

The number is reported scrub speed, in MiB/s.
The resolution is limited by the reported duration, which only has a
resolution of 1 second.

	Old		New		Diff
SSD	455.3		466.332		+2.42%
HDD	103.927 	98.012		-5.69%

Comprehensive test methodology is in the cover letter of the patch.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-01-07 14:18:26 +01:00
..
tests btrfs: track the csum, extent, and free space trees in a rb tree 2022-01-03 15:09:50 +01:00
acl.c overlayfs update for 5.15 2021-09-02 09:21:27 -07:00
async-thread.c btrfs: fix memory ordering between normal and ordered work functions 2021-11-16 16:50:23 +01:00
async-thread.h
backref.c btrfs: stop accessing ->extent_root directly 2022-01-03 15:09:49 +01:00
backref.h btrfs: remove ignore_offset argument from btrfs_find_all_roots() 2021-08-23 13:19:01 +02:00
block-group.c btrfs: make send work with concurrent block group relocation 2022-01-07 14:18:23 +01:00
block-group.h btrfs: fix deadlock between chunk allocation and chunk btree modifications 2021-10-26 19:08:07 +02:00
block-rsv.c btrfs: reserve extra space for the free space tree 2022-01-07 14:18:25 +01:00
block-rsv.h btrfs: init root block_rsv at init root time 2022-01-03 15:09:48 +01:00
btrfs_inode.h btrfs: only copy dir index keys when logging a directory 2022-01-03 15:09:42 +01:00
check-integrity.c btrfs: check-integrity: stop storing the block device name in btrfsic_dev_state 2021-10-26 19:08:07 +02:00
check-integrity.h
compression.c btrfs: set BTRFS_FS_STATE_NO_CSUMS if we fail to load the csum root 2022-01-03 15:09:49 +01:00
compression.h btrfs: determine stripe boundary at bio allocation time in btrfs_submit_compressed_write 2021-10-26 19:08:04 +02:00
ctree.c btrfs: refactor unlock_up 2022-01-07 14:18:26 +01:00
ctree.h btrfs: remove reada infrastructure 2022-01-07 14:18:26 +01:00
delalloc-space.c btrfs: change root to fs_info for btrfs_reserve_metadata_bytes 2022-01-03 15:09:45 +01:00
delalloc-space.h
delayed-inode.c btrfs: add an inode-item.h 2022-01-07 14:18:23 +01:00
delayed-inode.h
delayed-ref.c btrfs: reserve extra space for the free space tree 2022-01-07 14:18:25 +01:00
delayed-ref.h btrfs: make btrfs_ref::real_root optional 2021-10-26 19:08:06 +02:00
dev-replace.c btrfs: remove reada infrastructure 2022-01-07 14:18:26 +01:00
dev-replace.h
dir-item.c btrfs: drop the _nr from the item helpers 2022-01-03 15:09:43 +01:00
discard.c btrfs: fix typos in comments 2021-06-22 14:11:57 +02:00
discard.h
disk-io.c btrfs: remove reada infrastructure 2022-01-07 14:18:26 +01:00
disk-io.h btrfs: track the csum, extent, and free space trees in a rb tree 2022-01-03 15:09:50 +01:00
export.c
export.h
extent_io.c btrfs: remove reada infrastructure 2022-01-07 14:18:26 +01:00
extent_io.h btrfs: cleanup for extent_write_locked_range() 2021-10-26 19:08:04 +02:00
extent_map.c btrfs: rename btrfs_bio to btrfs_io_context 2021-10-26 19:08:02 +02:00
extent_map.h
extent-io-tree.h
extent-tree.c btrfs: zoned: fix chunk allocation condition for zoned allocator 2022-01-07 14:18:26 +01:00
file-item.c btrfs: stop accessing ->csum_root directly 2022-01-03 15:09:49 +01:00
file.c btrfs: fix deadlock due to page faults during direct IO reads and writes 2021-11-09 13:46:07 +01:00
free-space-cache.c btrfs: add inode to truncate control 2022-01-07 14:18:24 +01:00
free-space-cache.h btrfs: change name and type of private member of btrfs_free_space_ctl 2022-01-03 15:09:50 +01:00
free-space-tree.c btrfs: track the csum, extent, and free space trees in a rb tree 2022-01-03 15:09:50 +01:00
free-space-tree.h
inode-item.c btrfs: make should_throttle loop local in btrfs_truncate_inode_items 2022-01-07 14:18:25 +01:00
inode-item.h btrfs: add inode to truncate control 2022-01-07 14:18:24 +01:00
inode.c btrfs: add inode to truncate control 2022-01-07 14:18:24 +01:00
ioctl.c btrfs: skip transaction commit after failure to create subvolume 2022-01-07 14:18:26 +01:00
Kconfig btrfs: disable build on platforms having page size 256K 2021-06-22 14:11:57 +02:00
locking.c btrfs: fix typos in comments 2021-06-22 14:11:57 +02:00
locking.h btrfs: assert that extent buffers are write locked instead of only locked 2021-10-26 19:08:02 +02:00
lzo.c for-5.16-rc2-tag 2021-11-26 11:24:32 -08:00
Makefile btrfs: remove reada infrastructure 2022-01-07 14:18:26 +01:00
misc.h btrfs: use correct header for div_u64 in misc.h 2021-09-07 14:29:50 +02:00
ordered-data.c btrfs: zoned: fix double counting of split ordered extent 2021-09-07 14:30:41 +02:00
ordered-data.h btrfs: remove uptodate parameter from btrfs_dec_test_first_ordered_pending 2021-08-23 13:19:02 +02:00
orphan.c
print-tree.c btrfs: drop the _nr from the item helpers 2022-01-03 15:09:43 +01:00
print-tree.h
props.c btrfs: change root to fs_info for btrfs_reserve_metadata_bytes 2022-01-03 15:09:45 +01:00
props.h
qgroup.c btrfs: stop accessing ->extent_root directly 2022-01-03 15:09:49 +01:00
qgroup.h btrfs: fix lock inversion problem when doing qgroup extent tracing 2021-07-22 15:50:07 +02:00
raid56.c btrfs: remove btrfs_raid_bio::fs_info member 2021-10-26 19:08:03 +02:00
raid56.h btrfs: remove btrfs_raid_bio::fs_info member 2021-10-26 19:08:03 +02:00
rcu-string.h
ref-verify.c btrfs: stop accessing ->extent_root directly 2022-01-03 15:09:49 +01:00
ref-verify.h
reflink.c btrfs: drop the _nr from the item helpers 2022-01-03 15:09:43 +01:00
reflink.h
relocation.c btrfs: add an inode-item.h 2022-01-07 14:18:23 +01:00
root-tree.c btrfs: change root to fs_info for btrfs_reserve_metadata_bytes 2022-01-03 15:09:45 +01:00
scrub.c btrfs: remove reada infrastructure 2022-01-07 14:18:26 +01:00
send.c btrfs: make send work with concurrent block group relocation 2022-01-07 14:18:23 +01:00
send.h btrfs: send: prepare for v2 protocol 2021-10-29 12:38:43 +02:00
space-info.c btrfs: don't use the extent_root in flush_space 2022-01-03 15:09:48 +01:00
space-info.h btrfs: change root to fs_info for btrfs_reserve_metadata_bytes 2022-01-03 15:09:45 +01:00
struct-funcs.c btrfs: add special case to setget helpers for 64k pages 2021-08-23 13:18:58 +02:00
subpage.c btrfs: handle page locking in btrfs_page_end_writer_lock with no writers 2021-10-26 19:08:05 +02:00
subpage.h btrfs: rework page locking in __extent_writepage() 2021-10-26 19:08:05 +02:00
super.c btrfs: remove reada infrastructure 2022-01-07 14:18:26 +01:00
sysfs.c btrfs: sysfs: add devinfo/fsid to retrieve actual fsid from the device 2022-01-07 14:18:25 +01:00
sysfs.h
transaction.c btrfs: make send work with concurrent block group relocation 2022-01-07 14:18:23 +01:00
transaction.h btrfs: remove trans_handle->root 2022-01-03 15:09:47 +01:00
tree-checker.c btrfs: rename btrfs_item_end_nr to btrfs_item_data_end 2022-01-03 15:09:43 +01:00
tree-checker.h
tree-defrag.c btrfs: remove unnecessary extent root check in btrfs_defrag_leaves 2022-01-03 15:09:48 +01:00
tree-log.c btrfs: do not check -EAGAIN when truncating inodes in the log root 2022-01-07 14:18:25 +01:00
tree-log.h btrfs: change error handling for btrfs_delete_*_in_log 2021-10-26 19:08:05 +02:00
tree-mod-log.c btrfs: fix race when picking most recent mod log operation for an old root 2021-04-20 19:27:17 +02:00
tree-mod-log.h btrfs: add and use helper to get lowest sequence number for the tree mod log 2021-04-19 17:25:17 +02:00
ulist.c
ulist.h
uuid-tree.c btrfs: drop the _nr from the item helpers 2022-01-03 15:09:43 +01:00
verity.c btrfs: drop the _nr from the item helpers 2022-01-03 15:09:43 +01:00
volumes.c btrfs: remove reada infrastructure 2022-01-07 14:18:26 +01:00
volumes.h btrfs: remove reada infrastructure 2022-01-07 14:18:26 +01:00
xattr.c btrfs: drop the _nr from the item helpers 2022-01-03 15:09:43 +01:00
xattr.h
zlib.c Revert "btrfs: compression: drop kmap/kunmap from zlib" 2021-10-29 13:03:05 +02:00
zoned.c btrfs: zoned: fix chunk allocation condition for zoned allocator 2022-01-07 14:18:26 +01:00
zoned.h btrfs: zoned: fix chunk allocation condition for zoned allocator 2022-01-07 14:18:26 +01:00
zstd.c lib: zstd: Add kernel-specific API 2021-11-08 16:55:21 -08:00