On Fri, Oct 31, 2014 at 09:49:34AM -0400, Josef Bacik wrote:
> Our gluster boxes were spending lots of time in statfs because our fs'es are
> huge. The problem is statfs loops through all of the block groups looking for
> read only block groups, and when you have several terabytes worth of data that
> ends up being a lot of block groups. Move the read only block groups onto a
> read only list and only proces that list in
> btrfs_account_ro_block_groups_free_space to reduce the amount of churn.
> Thanks,
Looks good.
Reviewed-by: Liu Bo <bo.li....@oracle.com>
-liubo
>
> Signed-off-by: Josef Bacik <jba...@fb.com>
> ---
> V1->V2:
> -list_for_each_entry was using the wrong ->member name.
>
> fs/btrfs/ctree.h | 4 ++++
> fs/btrfs/extent-tree.c | 36 +++++++++++++-----------------------
> 2 files changed, 17 insertions(+), 23 deletions(-)
>
> diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
> index d557264e..438f087 100644
> --- a/fs/btrfs/ctree.h
> +++ b/fs/btrfs/ctree.h
> @@ -1170,6 +1170,7 @@ struct btrfs_space_info {
> struct percpu_counter total_bytes_pinned;
>
> struct list_head list;
> + struct list_head ro_bgs;
>
> struct rw_semaphore groups_sem;
> /* for block groups in our same type */
> @@ -1305,6 +1306,9 @@ struct btrfs_block_group_cache {
>
> /* For delayed block group creation or deletion of empty block groups */
> struct list_head bg_list;
> +
> + /* For read-only block groups */
> + struct list_head ro_list;
> };
>
> /* delayed seq elem */
> diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
> index 0d599ba..f51004f 100644
> --- a/fs/btrfs/extent-tree.c
> +++ b/fs/btrfs/extent-tree.c
> @@ -3518,6 +3518,7 @@ static int update_space_info(struct btrfs_fs_info
> *info, u64 flags,
> found->chunk_alloc = 0;
> found->flush = 0;
> init_waitqueue_head(&found->wait);
> + INIT_LIST_HEAD(&found->ro_bgs);
>
> ret = kobject_init_and_add(&found->kobj, &space_info_ktype,
> info->space_info_kobj, "%s",
> @@ -8525,6 +8526,7 @@ static int set_block_group_ro(struct
> btrfs_block_group_cache *cache, int force)
> min_allocable_bytes <= sinfo->total_bytes) {
> sinfo->bytes_readonly += num_bytes;
> cache->ro = 1;
> + list_add_tail(&cache->ro_list, &sinfo->ro_bgs);
> ret = 0;
> }
> out:
> @@ -8579,15 +8581,20 @@ int btrfs_force_chunk_alloc(struct btrfs_trans_handle
> *trans,
>
> /*
> * helper to account the unused space of all the readonly block group in the
> - * list. takes mirrors into account.
> + * space_info. takes mirrors into account.
> */
> -static u64 __btrfs_get_ro_block_group_free_space(struct list_head
> *groups_list)
> +u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
> {
> struct btrfs_block_group_cache *block_group;
> u64 free_bytes = 0;
> int factor;
>
> - list_for_each_entry(block_group, groups_list, list) {
> + /* It's df, we don't care if it's racey */
> + if (list_empty(&sinfo->ro_bgs))
> + return 0;
> +
> + spin_lock(&sinfo->lock);
> + list_for_each_entry(block_group, &sinfo->ro_bgs, ro_list) {
> spin_lock(&block_group->lock);
>
> if (!block_group->ro) {
> @@ -8608,26 +8615,6 @@ static u64
> __btrfs_get_ro_block_group_free_space(struct list_head *groups_list)
>
> spin_unlock(&block_group->lock);
> }
> -
> - return free_bytes;
> -}
> -
> -/*
> - * helper to account the unused space of all the readonly block group in the
> - * space_info. takes mirrors into account.
> - */
> -u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
> -{
> - int i;
> - u64 free_bytes = 0;
> -
> - spin_lock(&sinfo->lock);
> -
> - for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
> - if (!list_empty(&sinfo->block_groups[i]))
> - free_bytes += __btrfs_get_ro_block_group_free_space(
> - &sinfo->block_groups[i]);
> -
> spin_unlock(&sinfo->lock);
>
> return free_bytes;
> @@ -8647,6 +8634,7 @@ void btrfs_set_block_group_rw(struct btrfs_root *root,
> cache->bytes_super - btrfs_block_group_used(&cache->item);
> sinfo->bytes_readonly -= num_bytes;
> cache->ro = 0;
> + list_del_init(&cache->ro_list);
> spin_unlock(&cache->lock);
> spin_unlock(&sinfo->lock);
> }
> @@ -9016,6 +9004,7 @@ btrfs_create_block_group_cache(struct btrfs_root *root,
> u64 start, u64 size)
> INIT_LIST_HEAD(&cache->list);
> INIT_LIST_HEAD(&cache->cluster_list);
> INIT_LIST_HEAD(&cache->bg_list);
> + INIT_LIST_HEAD(&cache->ro_list);
> btrfs_init_free_space_ctl(cache);
>
> return cache;
> @@ -9425,6 +9414,7 @@ int btrfs_remove_block_group(struct btrfs_trans_handle
> *trans,
> * are still on the list after taking the semaphore
> */
> list_del_init(&block_group->list);
> + list_del_init(&block_group->ro_list);
> if (list_empty(&block_group->space_info->block_groups[index])) {
> kobj = block_group->space_info->block_group_kobjs[index];
> block_group->space_info->block_group_kobjs[index] = NULL;
> --
> 1.8.3.1
>
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