This patch is a small performance optimization to get rid of a spin
lock, where instead an atomic64_t can be used.
Signed-off-by: Sargun Dhillon <sar...@sargun.me>
---
fs/btrfs/ctree.h | 4 ++--
fs/btrfs/disk-io.c | 3 +--
fs/btrfs/extent-tree.c | 4 +---
fs/btrfs/volumes.c | 26 +++++++-------------------
4 files changed, 11 insertions(+), 26 deletions(-)
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 643c70d..01bf42c 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -40,6 +40,7 @@
#include <linux/sizes.h>
#include <linux/dynamic_debug.h>
#include <linux/refcount.h>
+#include <linux/types.h>
#include "extent_io.h"
#include "extent_map.h"
#include "async-thread.h"
@@ -748,8 +749,7 @@ struct btrfs_fs_info {
struct rb_root block_group_cache_tree;
/* keep track of unallocated space */
- spinlock_t free_chunk_lock;
- u64 free_chunk_space;
+ atomic64_t free_chunk_space;
struct extent_io_tree freed_extents[2];
struct extent_io_tree *pinned_extents;
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 8685d67..3700b68 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -2626,7 +2626,6 @@ int open_ctree(struct super_block *sb,
spin_lock_init(&fs_info->fs_roots_radix_lock);
spin_lock_init(&fs_info->delayed_iput_lock);
spin_lock_init(&fs_info->defrag_inodes_lock);
- spin_lock_init(&fs_info->free_chunk_lock);
spin_lock_init(&fs_info->tree_mod_seq_lock);
spin_lock_init(&fs_info->super_lock);
spin_lock_init(&fs_info->qgroup_op_lock);
@@ -2667,7 +2666,7 @@ int open_ctree(struct super_block *sb,
fs_info->max_inline = BTRFS_DEFAULT_MAX_INLINE;
fs_info->metadata_ratio = 0;
fs_info->defrag_inodes = RB_ROOT;
- fs_info->free_chunk_space = 0;
+ atomic64_set(&fs_info->free_chunk_space, 0);
fs_info->tree_mod_log = RB_ROOT;
fs_info->commit_interval = BTRFS_DEFAULT_COMMIT_INTERVAL;
fs_info->avg_delayed_ref_runtime = NSEC_PER_SEC >> 6; /* div by 64 */
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index e390451..955733c 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -4645,9 +4645,7 @@ static int can_overcommit(struct btrfs_root *root,
used += space_info->bytes_may_use;
- spin_lock(&fs_info->free_chunk_lock);
- avail = fs_info->free_chunk_space;
- spin_unlock(&fs_info->free_chunk_lock);
+ avail = atomic64_read(&fs_info->free_chunk_space);
/*
* If we have dup, raid1 or raid10 then only half of the free
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 017b67d..0123974 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -2417,9 +2417,7 @@ int btrfs_init_new_device(struct btrfs_fs_info *fs_info,
const char *device_path
fs_info->fs_devices->total_devices++;
fs_info->fs_devices->total_rw_bytes += device->total_bytes;
- spin_lock(&fs_info->free_chunk_lock);
- fs_info->free_chunk_space += device->total_bytes;
- spin_unlock(&fs_info->free_chunk_lock);
+ atomic64_add(device->total_bytes, &fs_info->free_chunk_space);
if (!blk_queue_nonrot(q))
fs_info->fs_devices->rotating = 1;
@@ -2874,9 +2872,7 @@ int btrfs_remove_chunk(struct btrfs_trans_handle *trans,
mutex_lock(&fs_info->chunk_mutex);
btrfs_device_set_bytes_used(device,
device->bytes_used - dev_extent_len);
- spin_lock(&fs_info->free_chunk_lock);
- fs_info->free_chunk_space += dev_extent_len;
- spin_unlock(&fs_info->free_chunk_lock);
+ atomic64_add(dev_extent_len,
&fs_info->free_chunk_space);
btrfs_clear_space_info_full(fs_info);
mutex_unlock(&fs_info->chunk_mutex);
}
@@ -4409,9 +4405,7 @@ int btrfs_shrink_device(struct btrfs_device *device, u64
new_size)
btrfs_device_set_total_bytes(device, new_size);
if (device->writeable) {
device->fs_devices->total_rw_bytes -= diff;
- spin_lock(&fs_info->free_chunk_lock);
- fs_info->free_chunk_space -= diff;
- spin_unlock(&fs_info->free_chunk_lock);
+ atomic64_sub(diff, &fs_info->free_chunk_space);
}
mutex_unlock(&fs_info->chunk_mutex);
@@ -4535,9 +4529,7 @@ int btrfs_shrink_device(struct btrfs_device *device, u64
new_size)
btrfs_device_set_total_bytes(device, old_size);
if (device->writeable)
device->fs_devices->total_rw_bytes += diff;
- spin_lock(&fs_info->free_chunk_lock);
- fs_info->free_chunk_space += diff;
- spin_unlock(&fs_info->free_chunk_lock);
+ atomic64_add(diff, &fs_info->free_chunk_space);
mutex_unlock(&fs_info->chunk_mutex);
}
return ret;
@@ -4882,9 +4874,7 @@ static int __btrfs_alloc_chunk(struct btrfs_trans_handle
*trans,
btrfs_device_set_bytes_used(map->stripes[i].dev, num_bytes);
}
- spin_lock(&info->free_chunk_lock);
- info->free_chunk_space -= (stripe_size * map->num_stripes);
- spin_unlock(&info->free_chunk_lock);
+ atomic64_sub((stripe_size * map->num_stripes), &info->free_chunk_space);
free_extent_map(em);
check_raid56_incompat_flag(info, type);
@@ -6684,10 +6674,8 @@ static int read_one_dev(struct btrfs_fs_info *fs_info,
device->in_fs_metadata = 1;
if (device->writeable && !device->is_tgtdev_for_dev_replace) {
device->fs_devices->total_rw_bytes += device->total_bytes;
- spin_lock(&fs_info->free_chunk_lock);
- fs_info->free_chunk_space += device->total_bytes -
- device->bytes_used;
- spin_unlock(&fs_info->free_chunk_lock);
+ atomic64_add(device->total_bytes - device->bytes_used,
+ &fs_info->free_chunk_space);
}
ret = 0;
return ret;
--
2.9.3
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