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author | David Sterba <dsterba@suse.com> | 2023-12-06 17:16:03 +0300 |
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committer | David Sterba <dsterba@suse.com> | 2023-12-16 01:01:03 +0300 |
commit | 6140ba8a0a1460986ee98b4062df7d4876b88295 (patch) | |
tree | 78a270ae66e0f20c8d9a939cf9e62e20c79f7413 /fs/btrfs/ctree.h | |
parent | eefaf0a1a6f10726faa4d1b7800fdf307e97ef55 (diff) | |
download | linux-6140ba8a0a1460986ee98b4062df7d4876b88295.tar.xz |
btrfs: switch btrfs_root::delayed_nodes_tree to xarray from radix-tree
The radix-tree has been superseded by the xarray
(https://lwn.net/Articles/745073), this patch converts the
btrfs_root::delayed_nodes, the APIs are used in a simple way.
First idea is to do xa_insert() but this would require GFP_ATOMIC
allocation which we want to avoid if possible. The preload mechanism of
radix-tree can be emulated within the xarray API.
- xa_reserve() with GFP_NOFS outside of the lock, the reserved entry
is inserted atomically at most once
- xa_store() under a lock, in case something races in we can detect that
and xa_load() returns a valid pointer
All uses of xa_load() must check for a valid pointer in case they manage
to get between the xa_reserve() and xa_store(), this is handled in
btrfs_get_delayed_node().
Otherwise the functionality is equivalent, xarray implements the
radix-tree and there should be no performance difference.
The patch continues the efforts started in 253bf57555e451 ("btrfs: turn
delayed_nodes_tree into an XArray") and fixes the problems with locking
and GFP flags 088aea3b97e0ae ("Revert "btrfs: turn delayed_nodes_tree
into an XArray"").
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs/ctree.h')
-rw-r--r-- | fs/btrfs/ctree.h | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index 54fd4eb92745..70e828d33177 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -227,10 +227,10 @@ struct btrfs_root { struct rb_root inode_tree; /* - * radix tree that keeps track of delayed nodes of every inode, - * protected by inode_lock + * Xarray that keeps track of delayed nodes of every inode, protected + * by @inode_lock. */ - struct radix_tree_root delayed_nodes_tree; + struct xarray delayed_nodes; /* * right now this just gets used so that a root has its own devid * for stat. It may be used for more later |