提交 c759c4e1 编写于 作者: J Josef Bacik 提交者: Chris Mason

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: NJosef Bacik <jbacik@fb.com>
Signed-off-by: NChris Mason <clm@fb.com>
上级 a5e681d9
......@@ -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
......
......@@ -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 @@ static noinline int find_free_extent(struct btrfs_root *orig_root,
* 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 @@ static noinline int find_free_extent(struct btrfs_root *orig_root,
}
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 @@ static noinline int find_free_extent(struct btrfs_root *orig_root,
} 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:
......
......@@ -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;
}
......
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