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| author | Filipe Manana <fdmanana@suse.com> | 2024-05-06 13:27:29 +0100 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2024-07-11 15:33:17 +0200 |
| commit | e2844cce75c9e61a27dcc29f0773afe970cde296 (patch) | |
| tree | 7fa42f9d311b06f1015b5f4550d1f1f4b3e429ef /fs/btrfs/inode.c | |
| parent | d25f4ec17624b1b18ff2e0a3e9c2baa71c8a86f2 (diff) | |
| download | lwn-e2844cce75c9e61a27dcc29f0773afe970cde296.tar.gz lwn-e2844cce75c9e61a27dcc29f0773afe970cde296.zip | |
btrfs: remove inode_lock from struct btrfs_root and use xarray locks
Currently we use the spinlock inode_lock from struct btrfs_root to
serialize access to two different data structures:
1) The delayed inodes xarray (struct btrfs_root::delayed_nodes);
2) The inodes xarray (struct btrfs_root::inodes).
Instead of using our own lock, we can use the spinlock that is part of the
xarray implementation, by using the xa_lock() and xa_unlock() APIs and
using the xarray APIs with the double underscore prefix that don't take
the xarray locks and assume the caller is using xa_lock() and xa_unlock().
So remove the spinlock inode_lock from struct btrfs_root and use the
corresponding xarray locks. This brings 2 benefits:
1) We reduce the size of struct btrfs_root, from 1336 bytes down to
1328 bytes on a 64 bits release kernel config;
2) We reduce lock contention by not using anymore the same lock for
changing two different and unrelated xarrays.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs/inode.c')
| -rw-r--r-- | fs/btrfs/inode.c | 18 |
1 files changed, 8 insertions, 10 deletions
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index e05915133fd0..2a8bc014579e 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -5509,9 +5509,7 @@ static int btrfs_add_inode_to_root(struct btrfs_inode *inode, bool prealloc) return ret; } - spin_lock(&root->inode_lock); existing = xa_store(&root->inodes, ino, inode, GFP_ATOMIC); - spin_unlock(&root->inode_lock); if (xa_is_err(existing)) { ret = xa_err(existing); @@ -5531,16 +5529,16 @@ static void btrfs_del_inode_from_root(struct btrfs_inode *inode) struct btrfs_inode *entry; bool empty = false; - spin_lock(&root->inode_lock); - entry = xa_erase(&root->inodes, btrfs_ino(inode)); + xa_lock(&root->inodes); + entry = __xa_erase(&root->inodes, btrfs_ino(inode)); if (entry == inode) empty = xa_empty(&root->inodes); - spin_unlock(&root->inode_lock); + xa_unlock(&root->inodes); if (empty && btrfs_root_refs(&root->root_item) == 0) { - spin_lock(&root->inode_lock); + xa_lock(&root->inodes); empty = xa_empty(&root->inodes); - spin_unlock(&root->inode_lock); + xa_unlock(&root->inodes); if (empty) btrfs_add_dead_root(root); } @@ -10874,7 +10872,7 @@ struct btrfs_inode *btrfs_find_first_inode(struct btrfs_root *root, u64 min_ino) struct btrfs_inode *inode; unsigned long from = min_ino; - spin_lock(&root->inode_lock); + xa_lock(&root->inodes); while (true) { inode = xa_find(&root->inodes, &from, ULONG_MAX, XA_PRESENT); if (!inode) @@ -10883,9 +10881,9 @@ struct btrfs_inode *btrfs_find_first_inode(struct btrfs_root *root, u64 min_ino) break; from = btrfs_ino(inode) + 1; - cond_resched_lock(&root->inode_lock); + cond_resched_lock(&root->inodes.xa_lock); } - spin_unlock(&root->inode_lock); + xa_unlock(&root->inodes); return inode; } |