From: Qu Wenruo <wqu@suse.com>
To: linux-btrfs@vger.kernel.org
Subject: [PATCH RFC 39/39] btrfs: qgroup: Use backref cache to speed up old_roots search
Date: Tue, 17 Mar 2020 16:11:25 +0800 [thread overview]
Message-ID: <20200317081125.36289-40-wqu@suse.com> (raw)
In-Reply-To: <20200317081125.36289-1-wqu@suse.com>
Now use the backref cache backed backref walk mechanism.
This mechanism is trading memory usage for faster, and more qgroup
specific backref walk.
Compared to original btrfs_find_all_roots(), it has the extra behavior
difference:
- Skip non-subvolume tress from the very beginning
Since only subvolume trees contribute to qgroup numbers, skipping them
would save us time.
- Skip reloc trees earlier
Reloc trees doesn't contribute to qgroup, and btrfs_find_all_roots()
also doesn't account them, thus we don't need to account them.
Here we use the detached nodes in backref cache to skip them faster
and earlier.
- Cached results
Well, backref cache is obviously cached, right.
The major performance improvement happens for backref walk in commit
tree, one of the most obvious user is qgroup rescan.
Here is a small script to test it:
mkfs.btrfs -f $dev
mount $dev -o space_cache=v2 $mnt
btrfs subvolume create $mnt/src
for ((i = 0; i < 64; i++)); do
for (( j = 0; j < 16; j++)); do
xfs_io -f -c "pwrite 0 2k" $mnt/src/file_inline_$(($i * 16 + $j)) > /dev/null
done
xfs_io -f -c "pwrite 0 1M" $mnt/src/file_reg_$i > /dev/null
sync
btrfs subvol snapshot $mnt/src $mnt/snapshot_$i
done
sync
btrfs quota enable $mnt
btrfs quota rescan -w $mnt
Here is the benchmark for above small tests.
The performance material is the total execution time of get_old_roots()
for patched kernel (*), and find_all_roots() for original kernel.
*: With CONFIG_BTRFS_FS_CHECK_INTEGRITY disabled, as get_old_roots()
will call find_all_roots() to verify the result if that config is
enabled.
| Number of calls | Total exec time |
------------------------------------------------------
find_all_roots()| 732 | 529991034ns
get_old_roots() | 732 | 127998312ns
------------------------------------------------------
diff | 0.00 % | -75.8 %
Signed-off-by: Qu Wenruo <wqu@suse.com>
---
fs/btrfs/qgroup.c | 22 ++++++++++++----------
1 file changed, 12 insertions(+), 10 deletions(-)
diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index 58df89b03ce3..3db1a1f4ec1f 100644
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -2054,8 +2054,9 @@ int btrfs_qgroup_trace_extent_post(struct btrfs_fs_info *fs_info,
u64 bytenr = qrecord->bytenr;
int ret;
- ret = btrfs_find_all_roots(NULL, fs_info, bytenr, 0, &old_root, false);
- if (ret < 0) {
+ old_root = get_old_roots(fs_info, bytenr);
+ if (IS_ERR(old_root)) {
+ ret = PTR_ERR(old_root);
fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
btrfs_warn(fs_info,
"error accounting new delayed refs extent (err code: %d), quota inconsistent",
@@ -3001,12 +3002,12 @@ int btrfs_qgroup_account_extents(struct btrfs_trans_handle *trans)
* extent record
*/
if (WARN_ON(!record->old_roots)) {
- /* Search commit root to find old_roots */
- ret = btrfs_find_all_roots(NULL, fs_info,
- record->bytenr, 0,
- &record->old_roots, false);
- if (ret < 0)
+ record->old_roots = get_old_roots(fs_info,
+ record->bytenr);
+ if (IS_ERR(record->old_roots)) {
+ ret = PTR_ERR(record->old_roots);
goto cleanup;
+ }
}
/* Free the reserved data space */
@@ -3585,10 +3586,11 @@ static int qgroup_rescan_leaf(struct btrfs_trans_handle *trans,
else
num_bytes = found.offset;
- ret = btrfs_find_all_roots(NULL, fs_info, found.objectid, 0,
- &roots, false);
- if (ret < 0)
+ roots = get_old_roots(fs_info, found.objectid);
+ if (IS_ERR(roots)) {
+ ret = PTR_ERR(roots);
goto out;
+ }
/* For rescan, just pass old_roots as NULL */
ret = btrfs_qgroup_account_extent(trans, found.objectid,
num_bytes, NULL, roots);
--
2.25.1
next prev parent reply other threads:[~2020-03-17 8:13 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-17 8:10 [PATCH RFC 00/39] btrfs: qgroup: Use backref cache based backref walk for commit roots Qu Wenruo
2020-03-17 8:10 ` [PATCH RFC 01/39] btrfs: backref: Introduce the skeleton of btrfs_backref_iter Qu Wenruo
2020-03-19 14:46 ` Josef Bacik
2020-03-17 8:10 ` [PATCH RFC 02/39] btrfs: backref: Implement btrfs_backref_iter_next() Qu Wenruo
2020-03-19 15:05 ` Josef Bacik
2020-03-17 8:10 ` [PATCH RFC 03/39] btrfs: relocation: Use btrfs_backref_iter infrastructure Qu Wenruo
2020-03-19 15:16 ` Josef Bacik
2020-03-17 8:10 ` [PATCH RFC 04/39] btrfs: relocation: Rename mark_block_processed() and __mark_block_processed() Qu Wenruo
2020-03-19 15:18 ` Josef Bacik
2020-03-17 8:10 ` [PATCH RFC 05/39] btrfs: relocation: Add backref_cache::pending_edge and backref_cache::useless_node members Qu Wenruo
2020-03-19 15:21 ` Josef Bacik
2020-03-17 8:10 ` [PATCH RFC 06/39] btrfs: relocation: Add backref_cache::fs_info member Qu Wenruo
2020-03-19 15:21 ` Josef Bacik
2020-03-17 8:10 ` [PATCH RFC 07/39] btrfs: relocation: Make reloc root search specific for relocation backref cache Qu Wenruo
2020-03-19 15:27 ` Josef Bacik
2020-03-19 15:28 ` Josef Bacik
2020-03-19 15:30 ` Josef Bacik
2020-03-17 8:10 ` [PATCH RFC 08/39] btrfs: relocation: Refactor direct tree backref processing into its own function Qu Wenruo
2020-03-19 15:31 ` Josef Bacik
2020-03-17 8:10 ` [PATCH RFC 09/39] btrfs: relocation: Refactor indirect " Qu Wenruo
2020-03-19 15:36 ` Josef Bacik
2020-03-17 8:10 ` [PATCH RFC 10/39] btrfs: relocation: Use wrapper to replace open-coded edge linking Qu Wenruo
2020-03-17 8:10 ` [PATCH RFC 11/39] btrfs: relocation: Specify essential members for alloc_backref_node() Qu Wenruo
2020-03-17 8:10 ` [PATCH RFC 12/39] btrfs: relocation: Remove the open-coded goto loop for breadth-first search Qu Wenruo
2020-03-19 15:42 ` Josef Bacik
2020-03-17 8:10 ` [PATCH RFC 13/39] btrfs: relocation: Refactor the finishing part of upper linkage into finish_upper_links() Qu Wenruo
2020-03-19 17:19 ` Josef Bacik
2020-03-17 8:11 ` [PATCH RFC 14/39] btrfs: relocation: Refactor the useless nodes handling into its own function Qu Wenruo
2020-03-19 17:21 ` Josef Bacik
2020-03-17 8:11 ` [PATCH RFC 15/39] btrfs: Move backref node/edge/cache structure to backref.h Qu Wenruo
2020-03-19 17:26 ` Josef Bacik
2020-03-17 8:11 ` [PATCH RFC 16/39] btrfs: Rename tree_entry to simple_node and export it Qu Wenruo
2020-03-17 8:11 ` [PATCH RFC 17/39] btrfs: Move backref_cache_init() to backref.c Qu Wenruo
2020-03-17 8:11 ` [PATCH RFC 18/39] btrfs: Move alloc_backref_node() " Qu Wenruo
2020-03-17 8:11 ` [PATCH RFC 19/39] btrfs: Move alloc_backref_edge() " Qu Wenruo
2020-03-17 8:11 ` [PATCH RFC 20/39] btrfs: Move link_backref_edge() " Qu Wenruo
2020-03-17 8:11 ` [PATCH RFC 21/39] btrfs: Move free_backref_node() and free_backref_edge() to backref.h Qu Wenruo
2020-03-17 8:11 ` [PATCH RFC 22/39] btrfs: Move drop_backref_node() and needed facilities " Qu Wenruo
2020-03-17 8:11 ` [PATCH RFC 23/39] btrfs: Rename remove_backref_node() to cleanup_backref_node() and move it to backref.c Qu Wenruo
2020-03-17 8:11 ` [PATCH RFC 24/39] btrfs: Rename backref_cache_cleanup() to backref_cache_release() " Qu Wenruo
2020-03-17 8:11 ` [PATCH RFC 25/39] btrfs: Rename backref_tree_panic() to backref_cache_panic(), " Qu Wenruo
2020-03-17 8:11 ` [PATCH RFC 26/39] btrfs: Rename should_ignore_root() to should_ignore_reloc_root() and export it Qu Wenruo
2020-03-17 8:11 ` [PATCH RFC 27/39] btrfs: relocation: Open-code read_fs_root() for handle_indirect_tree_backref() Qu Wenruo
2020-03-17 8:11 ` [PATCH RFC 28/39] btrfs: Rename handle_one_tree_block() to backref_cache_add_one_tree_block() and move it to backref.c Qu Wenruo
2020-03-17 8:11 ` [PATCH RFC 29/39] btrfs: Rename finish_upper_links() to backref_cache_finish_upper_links() " Qu Wenruo
2020-03-17 8:11 ` [PATCH RFC 30/39] btrfs: relocation: Move error handling of build_backref_tree() " Qu Wenruo
2020-03-17 8:11 ` [PATCH RFC 31/39] btrfs: relocation: Use btrfs_find_all_leaves() to locate parent tree leaves of a data extent Qu Wenruo
2020-03-17 8:11 ` [PATCH RFC 32/39] btrfs: backref: Only ignore reloc roots for indrect backref resolve if the backref cache is for reloction purpose Qu Wenruo
2020-03-17 8:11 ` [PATCH RFC 33/39] btrfs: qgroup: Introduce qgroup backref cache Qu Wenruo
2020-03-17 8:11 ` [PATCH RFC 34/39] btrfs: qgroup: Introduce qgroup_backref_cache_build() function Qu Wenruo
2020-03-17 8:11 ` [PATCH RFC 35/39] btrfs: qgroup: Introduce a function to iterate through backref_cache to find all parents for specified node Qu Wenruo
2020-03-17 8:11 ` [PATCH RFC 36/39] btrfs: qgroup: Introduce helpers to get needed tree block info Qu Wenruo
2020-03-17 8:11 ` [PATCH RFC 37/39] btrfs: qgroup: Introduce verification for function to ensure old roots ulist matches btrfs_find_all_roots() result Qu Wenruo
2020-03-17 8:11 ` [PATCH RFC 38/39] btrfs: qgroup: Introduce a new function to get old_roots ulist using backref cache Qu Wenruo
2020-03-17 8:11 ` Qu Wenruo [this message]
2020-03-19 17:26 ` [PATCH RFC 00/39] btrfs: qgroup: Use backref cache based backref walk for commit roots Josef Bacik
2020-03-25 18:30 ` David Sterba
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