Btrfs: alloc_mutex latency reduction
This releases the alloc_mutex in a few places that hold it for over long
operations. btrfs_lookup_block_group is changed so that it doesn't need
the mutex at all.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index eeb5afa..90504ba 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -483,6 +483,7 @@
struct btrfs_key key;
struct btrfs_block_group_item item;
struct btrfs_space_info *space_info;
+ spinlock_t lock;
u64 pinned;
u64 flags;
int cached;
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 72fa282..febc629 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -319,7 +319,7 @@
cache = btrfs_lookup_first_block_group(root->fs_info, last);
}
cache_miss = 0;
- cache = __btrfs_find_block_group(root, cache, last, data, 0);
+ cache = btrfs_find_block_group(root, cache, last, data, 0);
if (!cache)
goto no_cache;
*cache_ret = cache;
@@ -379,19 +379,25 @@
struct btrfs_block_group_cache *shint;
shint = btrfs_lookup_first_block_group(info, search_start);
if (shint && block_group_bits(shint, data) && !shint->ro) {
+ spin_lock(&shint->lock);
used = btrfs_block_group_used(&shint->item);
if (used + shint->pinned <
div_factor(shint->key.offset, factor)) {
+ spin_unlock(&shint->lock);
return shint;
}
+ spin_unlock(&shint->lock);
}
}
if (hint && !hint->ro && block_group_bits(hint, data)) {
+ spin_lock(&hint->lock);
used = btrfs_block_group_used(&hint->item);
if (used + hint->pinned <
div_factor(hint->key.offset, factor)) {
+ spin_unlock(&hint->lock);
return hint;
}
+ spin_unlock(&hint->lock);
last = hint->key.objectid + hint->key.offset;
} else {
if (hint)
@@ -413,6 +419,7 @@
}
cache = (struct btrfs_block_group_cache *)(unsigned long)ptr;
+ spin_lock(&cache->lock);
last = cache->key.objectid + cache->key.offset;
used = btrfs_block_group_used(&cache->item);
@@ -420,9 +427,11 @@
free_check = div_factor(cache->key.offset, factor);
if (used + cache->pinned < free_check) {
found_group = cache;
+ spin_unlock(&cache->lock);
goto found;
}
}
+ spin_unlock(&cache->lock);
cond_resched();
}
if (!wrapped) {
@@ -447,9 +456,7 @@
{
struct btrfs_block_group_cache *ret;
- mutex_lock(&root->fs_info->alloc_mutex);
ret = __btrfs_find_block_group(root, hint, search_start, data, owner);
- mutex_unlock(&root->fs_info->alloc_mutex);
return ret;
}
static u64 hash_extent_ref(u64 root_objectid, u64 ref_generation,
@@ -1262,21 +1269,25 @@
set_extent_bits(&info->block_group_cache, start, end,
BLOCK_GROUP_DIRTY, GFP_NOFS);
+ spin_lock(&cache->lock);
old_val = btrfs_block_group_used(&cache->item);
num_bytes = min(total, cache->key.offset - byte_in_group);
if (alloc) {
old_val += num_bytes;
cache->space_info->bytes_used += num_bytes;
+ btrfs_set_block_group_used(&cache->item, old_val);
+ spin_unlock(&cache->lock);
} else {
old_val -= num_bytes;
cache->space_info->bytes_used -= num_bytes;
+ btrfs_set_block_group_used(&cache->item, old_val);
+ spin_unlock(&cache->lock);
if (mark_free) {
set_extent_dirty(&info->free_space_cache,
bytenr, bytenr + num_bytes - 1,
GFP_NOFS);
}
}
- btrfs_set_block_group_used(&cache->item, old_val);
total -= num_bytes;
bytenr += num_bytes;
}
@@ -1325,14 +1336,18 @@
}
if (pin) {
if (cache) {
+ spin_lock(&cache->lock);
cache->pinned += len;
cache->space_info->bytes_pinned += len;
+ spin_unlock(&cache->lock);
}
fs_info->total_pinned += len;
} else {
if (cache) {
+ spin_lock(&cache->lock);
cache->pinned -= len;
cache->space_info->bytes_pinned -= len;
+ spin_unlock(&cache->lock);
}
fs_info->total_pinned -= len;
}
@@ -1380,6 +1395,11 @@
update_pinned_extents(root, start, end + 1 - start, 0);
clear_extent_dirty(unpin, start, end, GFP_NOFS);
set_extent_dirty(free_space_cache, start, end, GFP_NOFS);
+ if (need_resched()) {
+ mutex_unlock(&root->fs_info->alloc_mutex);
+ cond_resched();
+ mutex_lock(&root->fs_info->alloc_mutex);
+ }
}
mutex_unlock(&root->fs_info->alloc_mutex);
return 0;
@@ -1417,8 +1437,16 @@
&extent_item, sizeof(extent_item));
clear_extent_bits(&info->extent_ins, start, end, EXTENT_LOCKED,
GFP_NOFS);
- eb = read_tree_block(extent_root, ins.objectid, ins.offset,
- trans->transid);
+
+ eb = btrfs_find_tree_block(extent_root, ins.objectid,
+ ins.offset);
+
+ if (!btrfs_buffer_uptodate(eb, trans->transid)) {
+ mutex_unlock(&extent_root->fs_info->alloc_mutex);
+ btrfs_read_buffer(eb, trans->transid);
+ mutex_lock(&extent_root->fs_info->alloc_mutex);
+ }
+
btrfs_tree_lock(eb);
level = btrfs_header_level(eb);
if (level == 0) {
@@ -1437,6 +1465,11 @@
0, level,
btrfs_disk_key_objectid(&first));
BUG_ON(err);
+ if (need_resched()) {
+ mutex_unlock(&extent_root->fs_info->alloc_mutex);
+ cond_resched();
+ mutex_lock(&extent_root->fs_info->alloc_mutex);
+ }
}
btrfs_free_path(path);
return 0;
@@ -1640,15 +1673,28 @@
EXTENT_LOCKED);
if (ret)
break;
- update_pinned_extents(extent_root, start, end + 1 - start, 1);
clear_extent_bits(pending_del, start, end, EXTENT_LOCKED,
GFP_NOFS);
- ret = __free_extent(trans, extent_root,
- start, end + 1 - start,
- extent_root->root_key.objectid,
- 0, 0, 0, 0, 0);
+ if (!test_range_bit(&extent_root->fs_info->extent_ins,
+ start, end, EXTENT_LOCKED, 0)) {
+ update_pinned_extents(extent_root, start,
+ end + 1 - start, 1);
+ ret = __free_extent(trans, extent_root,
+ start, end + 1 - start,
+ extent_root->root_key.objectid,
+ 0, 0, 0, 0, 0);
+ } else {
+ clear_extent_bits(&extent_root->fs_info->extent_ins,
+ start, end, EXTENT_LOCKED, GFP_NOFS);
+ }
if (ret)
err = ret;
+
+ if (need_resched()) {
+ mutex_unlock(&extent_root->fs_info->alloc_mutex);
+ cond_resched();
+ mutex_lock(&extent_root->fs_info->alloc_mutex);
+ }
}
return err;
}
@@ -1768,12 +1814,12 @@
block_group = btrfs_lookup_first_block_group(info, hint_byte);
if (!block_group)
hint_byte = search_start;
- block_group = __btrfs_find_block_group(root, block_group,
+ block_group = btrfs_find_block_group(root, block_group,
hint_byte, data, 1);
if (last_ptr && *last_ptr == 0 && block_group)
hint_byte = block_group->key.objectid;
} else {
- block_group = __btrfs_find_block_group(root,
+ block_group = btrfs_find_block_group(root,
trans->block_group,
search_start, data, 1);
}
@@ -1895,7 +1941,7 @@
}
block_group = btrfs_lookup_first_block_group(info, search_start);
cond_resched();
- block_group = __btrfs_find_block_group(root, block_group,
+ block_group = btrfs_find_block_group(root, block_group,
search_start, data, 0);
goto check_failed;
@@ -3032,11 +3078,14 @@
u64 new_alloc_flags;
u64 calc;
+ spin_lock(&shrink_block_group->lock);
if (btrfs_block_group_used(&shrink_block_group->item) > 0) {
-
+ spin_unlock(&shrink_block_group->lock);
mutex_unlock(&root->fs_info->alloc_mutex);
+
trans = btrfs_start_transaction(root, 1);
mutex_lock(&root->fs_info->alloc_mutex);
+ spin_lock(&shrink_block_group->lock);
new_alloc_flags = update_block_group_flags(root,
shrink_block_group->flags);
@@ -3046,13 +3095,16 @@
} else {
calc = shrink_block_group->key.offset;
}
+ spin_unlock(&shrink_block_group->lock);
+
do_chunk_alloc(trans, root->fs_info->extent_root,
calc + 2 * 1024 * 1024, new_alloc_flags, force);
mutex_unlock(&root->fs_info->alloc_mutex);
btrfs_end_transaction(trans, root);
mutex_lock(&root->fs_info->alloc_mutex);
- }
+ } else
+ spin_unlock(&shrink_block_group->lock);
return 0;
}
@@ -3199,6 +3251,7 @@
mutex_unlock(&root->fs_info->alloc_mutex);
trans = btrfs_start_transaction(root, 1);
+
mutex_lock(&root->fs_info->alloc_mutex);
memcpy(&key, &shrink_block_group->key, sizeof(key));
@@ -3316,6 +3369,7 @@
break;
}
+ spin_lock_init(&cache->lock);
read_extent_buffer(leaf, &cache->item,
btrfs_item_ptr_offset(leaf, path->slots[0]),
sizeof(cache->item));
@@ -3343,10 +3397,12 @@
/* use EXTENT_LOCKED to prevent merging */
set_extent_bits(block_group_cache, found_key.objectid,
found_key.objectid + found_key.offset - 1,
- bit | EXTENT_LOCKED, GFP_NOFS);
+ EXTENT_LOCKED, GFP_NOFS);
set_state_private(block_group_cache, found_key.objectid,
(unsigned long)cache);
-
+ set_extent_bits(block_group_cache, found_key.objectid,
+ found_key.objectid + found_key.offset - 1,
+ bit | EXTENT_LOCKED, GFP_NOFS);
if (key.objectid >=
btrfs_super_total_bytes(&info->super_copy))
break;
@@ -3377,6 +3433,7 @@
BUG_ON(!cache);
cache->key.objectid = chunk_offset;
cache->key.offset = size;
+ spin_lock_init(&cache->lock);
btrfs_set_key_type(&cache->key, BTRFS_BLOCK_GROUP_ITEM_KEY);
btrfs_set_block_group_used(&cache->item, bytes_used);
@@ -3391,10 +3448,13 @@
bit = block_group_state_bits(type);
set_extent_bits(block_group_cache, chunk_offset,
chunk_offset + size - 1,
- bit | EXTENT_LOCKED, GFP_NOFS);
-
+ EXTENT_LOCKED, GFP_NOFS);
set_state_private(block_group_cache, chunk_offset,
(unsigned long)cache);
+ set_extent_bits(block_group_cache, chunk_offset,
+ chunk_offset + size - 1,
+ bit | EXTENT_LOCKED, GFP_NOFS);
+
ret = btrfs_insert_item(trans, extent_root, &cache->key, &cache->item,
sizeof(cache->item));
BUG_ON(ret);