On 7.06.2017 21:09, Sargun Dhillon wrote: > 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 <sargun@xxxxxxxxx> I've already sent similar patch 1 month ago: https://patchwork.kernel.org/patch/9720999/ > --- > 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; > -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
