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Btrfs: More throttle tuning

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* Make walk_down_tree wake up throttled tasks more often
* Make walk_down_tree call cond_resched during long loops
* As the size of the ref cache grows, wait longer in throttle
* Get rid of the reada code in walk_down_tree, the leaves don't get
  read anymore, thanks to the ref cache.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit is contained in:
Chris Mason
2008-08-04 08:20:15 -04:00
parent 65b51a009e
commit 2dd3e67b1e
3 changed files with 29 additions and 58 deletions
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59
fs/btrfs/extent-tree.c
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@ -2369,6 +2369,11 @@ static int noinline drop_leaf_ref_no_cache(struct btrfs_trans_handle *trans,
leaf_owner, leaf_generation,
key.objectid, key.offset, 0);
mutex_unlock(&root->fs_info->alloc_mutex);
atomic_inc(&root->fs_info->throttle_gen);
wake_up(&root->fs_info->transaction_throttle);
cond_resched();
BUG_ON(ret);
}
return 0;
@ -2389,6 +2394,11 @@ static int noinline drop_leaf_ref(struct btrfs_trans_handle *trans,
ref->owner, ref->generation,
info->objectid, info->offset, 0);
mutex_unlock(&root->fs_info->alloc_mutex);
atomic_inc(&root->fs_info->throttle_gen);
wake_up(&root->fs_info->transaction_throttle);
cond_resched();
BUG_ON(ret);
info++;
}
@ -2396,51 +2406,6 @@ static int noinline drop_leaf_ref(struct btrfs_trans_handle *trans,
return 0;
}
static void noinline reada_walk_down(struct btrfs_root *root,
struct extent_buffer *node,
int slot)
{
u64 bytenr;
u64 last = 0;
u32 nritems;
u32 refs;
u32 blocksize;
int ret;
int i;
int level;
int skipped = 0;
nritems = btrfs_header_nritems(node);
level = btrfs_header_level(node);
if (level)
return;
for (i = slot; i < nritems && skipped < 32; i++) {
bytenr = btrfs_node_blockptr(node, i);
if (last && ((bytenr > last && bytenr - last > 32 * 1024) ||
(last > bytenr && last - bytenr > 32 * 1024))) {
skipped++;
continue;
}
blocksize = btrfs_level_size(root, level - 1);
if (i != slot) {
ret = lookup_extent_ref(NULL, root, bytenr,
blocksize, &refs);
BUG_ON(ret);
if (refs != 1) {
skipped++;
continue;
}
}
ret = readahead_tree_block(root, bytenr, blocksize,
btrfs_node_ptr_generation(node, i));
last = bytenr + blocksize;
cond_resched();
if (ret)
break;
}
}
int drop_snap_lookup_refcount(struct btrfs_root *root, u64 start, u64 len,
u32 *refs)
{
@ -2549,6 +2514,7 @@ static int noinline walk_down_tree(struct btrfs_trans_handle *trans,
atomic_inc(&root->fs_info->throttle_gen);
wake_up(&root->fs_info->transaction_throttle);
cond_resched();
continue;
}
@ -2578,8 +2544,6 @@ static int noinline walk_down_tree(struct btrfs_trans_handle *trans,
if (!next || !btrfs_buffer_uptodate(next, ptr_gen)) {
free_extent_buffer(next);
if (path->slots[*level] == 0)
reada_walk_down(root, cur, path->slots[*level]);
next = read_tree_block(root, bytenr, blocksize,
ptr_gen);
cond_resched();
@ -2601,6 +2565,7 @@ static int noinline walk_down_tree(struct btrfs_trans_handle *trans,
path->nodes[*level-1] = next;
*level = btrfs_header_level(next);
path->slots[*level] = 0;
cond_resched();
}
out:
WARN_ON(*level < 0);