[PATCH] Btrfs: balance delayed inode updates

[PATCH] Btrfs: balance delayed inode updates

[Josef Bacik]

While trying to reproduce a delayed ref problem I noticed the box kept falling
over using all 80gb of my ram with btrfs_inode's and btrfs_delayed_node's.
Turns out this is because we only throttle delayed inode updates in
btrfs_dirty_inode, which doesn't actually get called that often, especially when
all you are doing is creating a bunch of files.  So balance delayed inode
updates everytime we create a new inode.  With this patch we no longer use up
all of our ram with delayed inode updates.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fb.com>
---
 fs/btrfs/extent-tree.c | 1 +
 fs/btrfs/inode.c       | 4 ++++
 2 files changed, 5 insertions(+)

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 9c9ecc9..1d9d9ce 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -2660,6 +2660,7 @@ int btrfs_should_throttle_delayed_refs(struct btrfs_trans_handle *trans,
 		atomic_read(&trans->transaction->delayed_refs.num_entries);
 	u64 avg_runtime;
 
+	return 1;
 	smp_mb();
 	avg_runtime = fs_info->avg_delayed_ref_runtime;
 	if (num_entries * avg_runtime >= NSEC_PER_SEC)
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 1af34d0..d44ff9f 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -5795,6 +5795,7 @@ static int btrfs_mknod(struct inode *dir, struct dentry *dentry,
 	}
 out_unlock:
 	btrfs_end_transaction(trans, root);
+	btrfs_balance_delayed_items(root);
 	btrfs_btree_balance_dirty(root);
 	if (drop_inode) {
 		inode_dec_link_count(inode);
@@ -5868,6 +5869,7 @@ out_unlock:
 		inode_dec_link_count(inode);
 		iput(inode);
 	}
+	btrfs_balance_delayed_items(root);
 	btrfs_btree_balance_dirty(root);
 	return err;
 }
@@ -5926,6 +5928,7 @@ static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
 	}
 
 	btrfs_end_transaction(trans, root);
+	btrfs_balance_delayed_items(root);
 fail:
 	if (drop_inode) {
 		inode_dec_link_count(inode);
@@ -5992,6 +5995,7 @@ out_fail:
 	btrfs_end_transaction(trans, root);
 	if (drop_on_err)
 		iput(inode);
+	btrfs_balance_delayed_items(root);
 	btrfs_btree_balance_dirty(root);
 	return err;
 }
-- 
1.8.3.1

Re: [PATCH] Btrfs: balance delayed inode updates

[Josef Bacik]

On 02/06/2014 04:07 PM, Josef Bacik wrote:
> While trying to reproduce a delayed ref problem I noticed the box kept falling
> over using all 80gb of my ram with btrfs_inode's and btrfs_delayed_node's.
> Turns out this is because we only throttle delayed inode updates in
> btrfs_dirty_inode, which doesn't actually get called that often, especially when
> all you are doing is creating a bunch of files.  So balance delayed inode
> updates everytime we create a new inode.  With this patch we no longer use up
> all of our ram with delayed inode updates.  Thanks,
>
> Signed-off-by: Josef Bacik <jbacik@fb.com>
> ---
>   fs/btrfs/extent-tree.c | 1 +
>   fs/btrfs/inode.c       | 4 ++++
>   2 files changed, 5 insertions(+)
>
> diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
> index 9c9ecc9..1d9d9ce 100644
> --- a/fs/btrfs/extent-tree.c
> +++ b/fs/btrfs/extent-tree.c
> @@ -2660,6 +2660,7 @@ int btrfs_should_throttle_delayed_refs(struct btrfs_trans_handle *trans,
>   		atomic_read(&trans->transaction->delayed_refs.num_entries);
>   	u64 avg_runtime;
>
> +	return 1;
>   	smp_mb();

Do git add for the file I want, do git commit -a anyway.

Josef