From 97e728d4353f38c87bf0804cdfd79a9b13fc2c3e Mon Sep 17 00:00:00 2001 From: Josef Bacik Date: Tue, 21 Apr 2009 17:40:57 -0400 Subject: [PATCH] Btrfs: try to keep a healthy ratio of metadata vs data block groups This patch makes the chunk allocator keep a good ratio of metadata vs data block groups. By default for every 8 data block groups, we'll allocate 1 metadata chunk, or about 12% of the disk will be allocated for metadata. This can be changed by specifying the metadata_ratio mount option. This is simply the number of data block groups that have to be allocated to force a metadata chunk allocation. By making sure we allocate metadata chunks more often, we are less likely to get into situations where the whole disk has been allocated as data block groups. Signed-off-by: Josef Bacik Signed-off-by: Chris Mason --- fs/btrfs/ctree.h | 3 +++ fs/btrfs/disk-io.c | 1 + fs/btrfs/extent-tree.c | 28 +++++++++++++++++++++++++++- fs/btrfs/super.c | 12 +++++++++++- 4 files changed, 42 insertions(+), 2 deletions(-) diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index ad96495..213535f 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -881,6 +881,9 @@ struct btrfs_fs_info { u64 metadata_alloc_profile; u64 system_alloc_profile; + unsigned data_chunk_allocations; + unsigned metadata_ratio; + void *bdev_holder; }; diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index a6b8374..44c94d8 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -1604,6 +1604,7 @@ struct btrfs_root *open_ctree(struct super_block *sb, fs_info->btree_inode = new_inode(sb); fs_info->btree_inode->i_ino = 1; fs_info->btree_inode->i_nlink = 1; + fs_info->metadata_ratio = 8; fs_info->thread_pool_size = min_t(unsigned long, num_online_cpus() + 2, 8); diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index 178df4c..2895a83 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -1918,15 +1918,29 @@ void btrfs_delalloc_free_space(struct btrfs_root *root, struct inode *inode, spin_unlock(&info->lock); } +static void force_metadata_allocation(struct btrfs_fs_info *info) +{ + struct list_head *head = &info->space_info; + struct btrfs_space_info *found; + + rcu_read_lock(); + list_for_each_entry_rcu(found, head, list) { + if (found->flags & BTRFS_BLOCK_GROUP_METADATA) + found->force_alloc = 1; + } + rcu_read_unlock(); +} + static int do_chunk_alloc(struct btrfs_trans_handle *trans, struct btrfs_root *extent_root, u64 alloc_bytes, u64 flags, int force) { struct btrfs_space_info *space_info; + struct btrfs_fs_info *fs_info = extent_root->fs_info; u64 thresh; int ret = 0; - mutex_lock(&extent_root->fs_info->chunk_mutex); + mutex_lock(&fs_info->chunk_mutex); flags = btrfs_reduce_alloc_profile(extent_root, flags); @@ -1958,6 +1972,18 @@ static int do_chunk_alloc(struct btrfs_trans_handle *trans, } spin_unlock(&space_info->lock); + /* + * if we're doing a data chunk, go ahead and make sure that + * we keep a reasonable number of metadata chunks allocated in the + * FS as well. + */ + if (flags & BTRFS_BLOCK_GROUP_DATA) { + fs_info->data_chunk_allocations++; + if (!(fs_info->data_chunk_allocations % + fs_info->metadata_ratio)) + force_metadata_allocation(fs_info); + } + ret = btrfs_alloc_chunk(trans, extent_root, flags); if (ret) space_info->full = 1; diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index 9744af9..30c9a8c 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -68,7 +68,7 @@ enum { Opt_degraded, Opt_subvol, Opt_device, Opt_nodatasum, Opt_nodatacow, Opt_max_extent, Opt_max_inline, Opt_alloc_start, Opt_nobarrier, Opt_ssd, Opt_thread_pool, Opt_noacl, Opt_compress, Opt_notreelog, - Opt_flushoncommit, Opt_err, + Opt_ratio, Opt_flushoncommit, Opt_err, }; static match_table_t tokens = { @@ -87,6 +87,7 @@ static match_table_t tokens = { {Opt_noacl, "noacl"}, {Opt_notreelog, "notreelog"}, {Opt_flushoncommit, "flushoncommit"}, + {Opt_ratio, "metadata_ratio=%d"}, {Opt_err, NULL}, }; @@ -234,6 +235,15 @@ int btrfs_parse_options(struct btrfs_root *root, char *options) printk(KERN_INFO "btrfs: turning on flush-on-commit\n"); btrfs_set_opt(info->mount_opt, FLUSHONCOMMIT); break; + case Opt_ratio: + intarg = 0; + match_int(&args[0], &intarg); + if (intarg) { + info->metadata_ratio = intarg; + printk(KERN_INFO "btrfs: metadata ratio %d\n", + info->metadata_ratio); + } + break; default: break; } -- 2.7.4