For btrfs_add_delayed_tree_ref(), its ref_root parameter can be
different from its real root.
This is pretty common for reloc tree, in that case @ref_root is passed
as the original tree owner (source file tree).
However btrfs_add_delayed_tree_ref() uses @ref_root to determine whether
we should do heavy qgroup tracing for it, so for balance this could
cause a lot of unnecessary extent tracing.
This patch will introduce a parameter, @root for qgroup code to
determine whether we really need to do the heavy-lifting tracing work.
This patch would reduce the qgroup dirty extent number from 'number of
extents being relocated' to 0 for the transaction before real tree swap.
[[Benchmark]] (with all previous enhancement)
Hardware:
VM 4G vRAM, 8 vCPUs,
disk is using 'unsafe' cache mode,
backing device is SAMSUNG 850 evo SSD.
Host has 16G ram.
Mkfs parameter:
--nodesize 4K (To bump up tree size)
Initial subvolume contents:
4G data copied from /usr and /lib.
(With enough regular small files)
Snapshots:
16 snapshots of the original subvolume.
each snapshot has 3 random files modified.
balance parameter:
-m
So the content should be pretty similar to a real world root fs layout.
| v4.19-rc1 | w/ patchset | diff (*)
---------------------------------------------------------------
relocated extents | 22929 | 22975 | +0.0%
qgroup dirty extents | 227757 | 141239 | -38.0%
time (sys) | 65.253s | 37.466s | -42.6%
time (real) | 74.032s | 44.585s | -39.8%
Signed-off-by: Qu Wenruo <wqu@xxxxxxxx>
---
fs/btrfs/delayed-ref.c | 3 ++-
fs/btrfs/delayed-ref.h | 1 +
fs/btrfs/extent-tree.c | 8 ++++----
3 files changed, 7 insertions(+), 5 deletions(-)
diff --git a/fs/btrfs/delayed-ref.c b/fs/btrfs/delayed-ref.c
index 62ff545ba1f7..a2a5c777d8c2 100644
--- a/fs/btrfs/delayed-ref.c
+++ b/fs/btrfs/delayed-ref.c
@@ -710,6 +710,7 @@ static void init_delayed_ref_common(struct btrfs_fs_info *fs_info,
* transaction commits.
*/
int btrfs_add_delayed_tree_ref(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
u64 bytenr, u64 num_bytes, u64 parent,
u64 ref_root, int level, int action,
struct btrfs_delayed_extent_op *extent_op,
@@ -737,7 +738,7 @@ int btrfs_add_delayed_tree_ref(struct btrfs_trans_handle *trans,
}
if (test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags) &&
- is_fstree(ref_root)) {
+ is_fstree(root->root_key.objectid)) {
record = kmalloc(sizeof(*record), GFP_NOFS);
if (!record) {
kmem_cache_free(btrfs_delayed_tree_ref_cachep, ref);
diff --git a/fs/btrfs/delayed-ref.h b/fs/btrfs/delayed-ref.h
index d9f2a4ebd5db..a51560a3cb66 100644
--- a/fs/btrfs/delayed-ref.h
+++ b/fs/btrfs/delayed-ref.h
@@ -235,6 +235,7 @@ static inline void btrfs_put_delayed_ref_head(struct btrfs_delayed_ref_head *hea
}
int btrfs_add_delayed_tree_ref(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
u64 bytenr, u64 num_bytes, u64 parent,
u64 ref_root, int level, int action,
struct btrfs_delayed_extent_op *extent_op,
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 028d1a80d36f..d8a0746498ac 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -2040,7 +2040,7 @@ int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
owner, offset, BTRFS_ADD_DELAYED_REF);
if (owner < BTRFS_FIRST_FREE_OBJECTID) {
- ret = btrfs_add_delayed_tree_ref(trans, bytenr,
+ ret = btrfs_add_delayed_tree_ref(trans, root, bytenr,
num_bytes, parent,
root_objectid, (int)owner,
BTRFS_ADD_DELAYED_REF, NULL,
@@ -6993,7 +6993,7 @@ void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
root->root_key.objectid,
btrfs_header_level(buf), 0,
BTRFS_DROP_DELAYED_REF);
- ret = btrfs_add_delayed_tree_ref(trans, buf->start,
+ ret = btrfs_add_delayed_tree_ref(trans, root, buf->start,
buf->len, parent,
root->root_key.objectid,
btrfs_header_level(buf),
@@ -7072,7 +7072,7 @@ int btrfs_free_extent(struct btrfs_trans_handle *trans,
old_ref_mod = new_ref_mod = 0;
ret = 0;
} else if (owner < BTRFS_FIRST_FREE_OBJECTID) {
- ret = btrfs_add_delayed_tree_ref(trans, bytenr,
+ ret = btrfs_add_delayed_tree_ref(trans, root, bytenr,
num_bytes, parent,
root_objectid, (int)owner,
BTRFS_DROP_DELAYED_REF, NULL,
@@ -8293,7 +8293,7 @@ struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
btrfs_ref_tree_mod(root, ins.objectid, ins.offset, parent,
root_objectid, level, 0,
BTRFS_ADD_DELAYED_EXTENT);
- ret = btrfs_add_delayed_tree_ref(trans, ins.objectid,
+ ret = btrfs_add_delayed_tree_ref(trans, root, ins.objectid,
ins.offset, parent,
root_objectid, level,
BTRFS_ADD_DELAYED_EXTENT,
--
2.19.0
