From: Qu Wenruo <wqu@suse.com>
To: linux-btrfs@vger.kernel.org
Subject: [PATCH 40/40] btrfs: qgroup: Use backref cache to speed up old_roots search
Date: Mon, 23 Mar 2020 18:24:16 +0800 [thread overview]
Message-ID: <20200323102416.112862-41-wqu@suse.com> (raw)
In-Reply-To: <20200323102416.112862-1-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 b58821323512..964dddd81b1d 100644
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -2059,8 +2059,9 @@ 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",
@@ -3006,12 +3007,12 @@ 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 */
@@ -3590,10 +3591,11 @@ 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);
--
2.25.2
prev parent reply other threads:[~2020-03-23 10:26 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-23 10:23 [PATCH 00/40] btrfs: qgroup: Use backref cache based backref walk for commit roots Qu Wenruo
2020-03-23 10:23 ` [PATCH 01/40] btrfs: backref: Introduce the skeleton of btrfs_backref_iter Qu Wenruo
2020-03-23 12:51 ` Josef Bacik
2020-03-23 10:23 ` [PATCH 02/40] btrfs: backref: Implement btrfs_backref_iter_next() Qu Wenruo
2020-03-23 10:23 ` [PATCH 03/40] btrfs: relocation: Use btrfs_backref_iter infrastructure Qu Wenruo
2020-03-23 10:23 ` [PATCH 04/40] btrfs: relocation: Rename mark_block_processed() and __mark_block_processed() Qu Wenruo
2020-03-23 10:23 ` [PATCH 05/40] btrfs: relocation: Add backref_cache::pending_edge and backref_cache::useless_node members Qu Wenruo
2020-03-23 10:23 ` [PATCH 06/40] btrfs: relocation: Add backref_cache::fs_info member Qu Wenruo
2020-03-23 10:23 ` [PATCH 07/40] btrfs: relocation: Make reloc root search specific for relocation backref cache Qu Wenruo
2020-03-23 10:23 ` [PATCH 08/40] btrfs: relocation: Refactor direct tree backref processing into its own function Qu Wenruo
2020-03-23 10:23 ` [PATCH 09/40] btrfs: relocation: Refactor indirect " Qu Wenruo
2020-03-23 10:23 ` [PATCH 10/40] btrfs: relocation: Use wrapper to replace open-coded edge linking Qu Wenruo
2020-03-23 10:23 ` [PATCH 11/40] btrfs: relocation: Specify essential members for alloc_backref_node() Qu Wenruo
2020-03-23 10:23 ` [PATCH 12/40] btrfs: relocation: Remove the open-coded goto loop for breadth-first search Qu Wenruo
2020-03-23 10:23 ` [PATCH 13/40] btrfs: relocation: Refactor the finishing part of upper linkage into finish_upper_links() Qu Wenruo
2020-03-23 10:23 ` [PATCH 14/40] btrfs: relocation: Refactor the useless nodes handling into its own function Qu Wenruo
2020-03-23 10:23 ` [PATCH 15/40] btrfs: relocation: Add btrfs_ prefix for backref_node/edge/cache Qu Wenruo
2020-03-23 10:23 ` [PATCH 16/40] btrfs: Move btrfs_backref_(node|edge|cache) structures to backref.h Qu Wenruo
2020-03-23 10:23 ` [PATCH 17/40] btrfs: Rename tree_entry to simple_node and export it Qu Wenruo
2020-03-23 10:23 ` [PATCH 18/40] btrfs: Rename backref_cache_init() to btrfs_backref_cache_init() and move it to backref.c Qu Wenruo
2020-03-23 10:23 ` [PATCH 19/40] btrfs: Rename alloc_backref_node() to btrfs_backref_alloc_node() and move it backref.c Qu Wenruo
2020-03-23 10:23 ` [PATCH 20/40] btrfs: Rename alloc_backref_edge() to btrfs_backref_alloc_edge() " Qu Wenruo
2020-03-23 10:23 ` [PATCH 21/40] btrfs: Rename link_backref_edge() to btrfs_backref_link_edge() and move it backref.h Qu Wenruo
2020-03-23 10:23 ` [PATCH 22/40] btrfs: Rename free_backref_(node|edge) to btrfs_backref_free_(node|edge) and move them to backref.h Qu Wenruo
2020-03-23 10:23 ` [PATCH 23/40] btrfs: Rename drop_backref_node() to btrfs_backref_drop_node() and move its needed facilities " Qu Wenruo
2020-03-23 10:24 ` [PATCH 24/40] btrfs: Rename remove_backref_node() to btrfs_backref_cleanup_node() and move it to backref.c Qu Wenruo
2020-03-23 10:24 ` [PATCH 25/40] btrfs: Rename backref_cache_cleanup() to btrfs_backref_release_cache() " Qu Wenruo
2020-03-23 10:24 ` [PATCH 26/40] btrfs: Rename backref_tree_panic() to btrfs_backref_panic(), " Qu Wenruo
2020-03-23 10:24 ` [PATCH 27/40] btrfs: Rename should_ignore_root() to btrfs_should_ignore_reloc_root() and export it Qu Wenruo
2020-03-23 10:24 ` [PATCH 28/40] btrfs: relocation: Open-code read_fs_root() for handle_indirect_tree_backref() Qu Wenruo
2020-03-23 10:24 ` [PATCH 29/40] btrfs: Rename handle_one_tree_block() to btrfs_backref_add_tree_node() and move it to backref.c Qu Wenruo
2020-03-23 10:24 ` [PATCH 30/40] btrfs: Rename finish_upper_links() to btrfs_backref_finish_upper_links() " Qu Wenruo
2020-03-23 10:24 ` [PATCH 31/40] btrfs: relocation: Move error handling of build_backref_tree() " Qu Wenruo
2020-03-23 10:24 ` [PATCH 32/40] btrfs: relocation: Use btrfs_find_all_leaves() to locate parent tree leaves of a data extent Qu Wenruo
2020-03-23 10:24 ` [PATCH 33/40] btrfs: backref: Only ignore reloc roots for indrect backref resolve if the backref cache is for reloction purpose Qu Wenruo
2020-03-23 10:24 ` [PATCH 34/40] btrfs: qgroup: Introduce qgroup backref cache Qu Wenruo
2020-03-23 10:24 ` [PATCH 35/40] btrfs: qgroup: Introduce qgroup_backref_cache_build() function Qu Wenruo
2020-03-23 10:24 ` [PATCH 36/40] btrfs: qgroup: Introduce a function to iterate through backref_cache to find all parents for specified node Qu Wenruo
2020-03-23 10:24 ` [PATCH 37/40] btrfs: qgroup: Introduce helpers to get needed tree block info Qu Wenruo
2020-03-23 10:24 ` [PATCH 38/40] btrfs: qgroup: Introduce verification for function to ensure old roots ulist matches btrfs_find_all_roots() result Qu Wenruo
2020-03-23 10:24 ` [PATCH 39/40] btrfs: qgroup: Introduce a new function to get old_roots ulist using backref cache Qu Wenruo
2020-03-23 10:24 ` Qu Wenruo [this message]
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