diff options
author | Josef Bacik <jbacik@fb.com> | 2015-10-02 15:25:10 -0400 |
---|---|---|
committer | Chris Mason <clm@fb.com> | 2015-10-21 18:55:39 -0700 |
commit | c759c4e16179e47e099f491011e6acd7858f8625 (patch) | |
tree | 1b97ad895f5546f867d0b12df3910848e69f1016 /fs/btrfs | |
parent | a5e681d9bd641c4f0677e87d3a0c92a8f4f16293 (diff) | |
download | lwn-c759c4e16179e47e099f491011e6acd7858f8625.tar.gz lwn-c759c4e16179e47e099f491011e6acd7858f8625.zip |
Btrfs: don't keep trying to build clusters if we are fragmented
If we are extremely fragmented then we won't be able to create a free_cluster.
So if this happens set last_ptr->fragmented so that all future allcations will
give up trying to create a cluster. When we unpin extents we will unset
->fragmented if we free up a sufficient amount of space in a block group.
Thanks,
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
Diffstat (limited to 'fs/btrfs')
-rw-r--r-- | fs/btrfs/ctree.h | 3 | ||||
-rw-r--r-- | fs/btrfs/extent-tree.c | 102 | ||||
-rw-r--r-- | fs/btrfs/free-space-cache.c | 1 |
3 files changed, 82 insertions, 24 deletions
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index 78a8f56c7e88..ced08c9608e2 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -1232,6 +1232,9 @@ struct btrfs_free_cluster { /* first extent starting offset */ u64 window_start; + /* We did a full search and couldn't create a cluster */ + bool fragmented; + struct btrfs_block_group_cache *block_group; /* * when a cluster is allocated from a block group, we put the diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index 9f18eb0e86b6..475764502d42 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -6142,6 +6142,34 @@ void btrfs_prepare_extent_commit(struct btrfs_trans_handle *trans, update_global_block_rsv(fs_info); } +/* + * Returns the free cluster for the given space info and sets empty_cluster to + * what it should be based on the mount options. + */ +static struct btrfs_free_cluster * +fetch_cluster_info(struct btrfs_root *root, struct btrfs_space_info *space_info, + u64 *empty_cluster) +{ + struct btrfs_free_cluster *ret = NULL; + bool ssd = btrfs_test_opt(root, SSD); + + *empty_cluster = 0; + if (btrfs_mixed_space_info(space_info)) + return ret; + + if (ssd) + *empty_cluster = 2 * 1024 * 1024; + if (space_info->flags & BTRFS_BLOCK_GROUP_METADATA) { + ret = &root->fs_info->meta_alloc_cluster; + if (!ssd) + *empty_cluster = 64 * 1024; + } else if ((space_info->flags & BTRFS_BLOCK_GROUP_DATA) && ssd) { + ret = &root->fs_info->data_alloc_cluster; + } + + return ret; +} + static int unpin_extent_range(struct btrfs_root *root, u64 start, u64 end, const bool return_free_space) { @@ -6149,7 +6177,10 @@ static int unpin_extent_range(struct btrfs_root *root, u64 start, u64 end, struct btrfs_block_group_cache *cache = NULL; struct btrfs_space_info *space_info; struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv; + struct btrfs_free_cluster *cluster = NULL; u64 len; + u64 total_unpinned = 0; + u64 empty_cluster = 0; bool readonly; while (start <= end) { @@ -6158,8 +6189,14 @@ static int unpin_extent_range(struct btrfs_root *root, u64 start, u64 end, start >= cache->key.objectid + cache->key.offset) { if (cache) btrfs_put_block_group(cache); + total_unpinned = 0; cache = btrfs_lookup_block_group(fs_info, start); BUG_ON(!cache); /* Logic error */ + + cluster = fetch_cluster_info(root, + cache->space_info, + &empty_cluster); + empty_cluster <<= 1; } len = cache->key.objectid + cache->key.offset - start; @@ -6172,8 +6209,22 @@ static int unpin_extent_range(struct btrfs_root *root, u64 start, u64 end, } start += len; + total_unpinned += len; space_info = cache->space_info; + /* + * If this space cluster has been marked as fragmented and we've + * unpinned enough in this block group to potentially allow a + * cluster to be created inside of it go ahead and clear the + * fragmented check. + */ + if (cluster && cluster->fragmented && + total_unpinned > empty_cluster) { + spin_lock(&cluster->lock); + cluster->fragmented = 0; + spin_unlock(&cluster->lock); + } + spin_lock(&space_info->lock); spin_lock(&cache->lock); cache->pinned -= len; @@ -6911,7 +6962,7 @@ static noinline int find_free_extent(struct btrfs_root *orig_root, struct btrfs_block_group_cache *block_group = NULL; u64 search_start = 0; u64 max_extent_size = 0; - int empty_cluster = 2 * 1024 * 1024; + u64 empty_cluster = 0; struct btrfs_space_info *space_info; int loop = 0; int index = __get_raid_index(flags); @@ -6959,37 +7010,25 @@ static noinline int find_free_extent(struct btrfs_root *orig_root, spin_unlock(&space_info->lock); } - /* - * If the space info is for both data and metadata it means we have a - * small filesystem and we can't use the clustering stuff. - */ - if (btrfs_mixed_space_info(space_info)) - use_cluster = false; - - if (flags & BTRFS_BLOCK_GROUP_METADATA && use_cluster) { - last_ptr = &root->fs_info->meta_alloc_cluster; - if (!btrfs_test_opt(root, SSD)) - empty_cluster = 64 * 1024; - } - - if ((flags & BTRFS_BLOCK_GROUP_DATA) && use_cluster && - btrfs_test_opt(root, SSD)) { - last_ptr = &root->fs_info->data_alloc_cluster; - } - + last_ptr = fetch_cluster_info(orig_root, space_info, &empty_cluster); if (last_ptr) { spin_lock(&last_ptr->lock); if (last_ptr->block_group) hint_byte = last_ptr->window_start; + if (last_ptr->fragmented) { + /* + * We still set window_start so we can keep track of the + * last place we found an allocation to try and save + * some time. + */ + hint_byte = last_ptr->window_start; + use_cluster = false; + } spin_unlock(&last_ptr->lock); } search_start = max(search_start, first_logical_byte(root, 0)); search_start = max(search_start, hint_byte); - - if (!last_ptr) - empty_cluster = 0; - if (search_start == hint_byte) { block_group = btrfs_lookup_block_group(root->fs_info, search_start); @@ -7074,7 +7113,7 @@ have_block_group: * Ok we want to try and use the cluster allocator, so * lets look there */ - if (last_ptr) { + if (last_ptr && use_cluster) { struct btrfs_block_group_cache *used_block_group; unsigned long aligned_cluster; /* @@ -7200,6 +7239,16 @@ refill_cluster: } unclustered_alloc: + /* + * We are doing an unclustered alloc, set the fragmented flag so + * we don't bother trying to setup a cluster again until we get + * more space. + */ + if (unlikely(last_ptr)) { + spin_lock(&last_ptr->lock); + last_ptr->fragmented = 1; + spin_unlock(&last_ptr->lock); + } spin_lock(&block_group->free_space_ctl->tree_lock); if (cached && block_group->free_space_ctl->free_space < @@ -7361,6 +7410,11 @@ loop: } else if (!ins->objectid) { ret = -ENOSPC; } else if (ins->objectid) { + if (!use_cluster && last_ptr) { + spin_lock(&last_ptr->lock); + last_ptr->window_start = ins->objectid; + spin_unlock(&last_ptr->lock); + } ret = 0; } out: diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c index c0eb84ecb78f..a5922e814ada 100644 --- a/fs/btrfs/free-space-cache.c +++ b/fs/btrfs/free-space-cache.c @@ -3063,6 +3063,7 @@ void btrfs_init_free_cluster(struct btrfs_free_cluster *cluster) spin_lock_init(&cluster->refill_lock); cluster->root = RB_ROOT; cluster->max_size = 0; + cluster->fragmented = false; INIT_LIST_HEAD(&cluster->block_group_list); cluster->block_group = NULL; } |