Commit 1e8f9158 authored by Wang Shilong's avatar Wang Shilong Committed by Josef Bacik
Browse files

Btrfs: introduce qgroup_ulist to avoid frequently allocating/freeing ulist 



When doing qgroup accounting, we call ulist_alloc()/ulist_free() every time
when we want to walk qgroup tree.

By introducing 'qgroup_ulist', we only need to call ulist_alloc()/ulist_free()
once. This reduce some sys time to allocate memory, see the measurements below

fsstress -p 4 -n 10000 -d $dir

With this patch:

real    0m50.153s
user    0m0.081s
sys     0m6.294s

real    0m51.113s
user    0m0.092s
sys     0m6.220s

real    0m52.610s
user    0m0.096s
sys     0m6.125s	avg 6.213
-----------------------------------------------------
Without the patch:

real    0m54.825s
user    0m0.061s
sys     0m10.665s

real    1m6.401s
user    0m0.089s
sys     0m11.218s

real    1m13.768s
user    0m0.087s
sys     0m10.665s       avg 10.849

we can see the sys time reduce ~43%.

Signed-off-by: default avatarWang Shilong <wangsl-fnst@cn.fujitsu.com>
Signed-off-by: default avatarJosef Bacik <jbacik@fusionio.com>
parent 85965600

fs/btrfs/ctree.h

+6 −0
Original line number Diff line number Diff line
@@ -1594,6 +1594,12 @@ struct btrfs_fs_info { 
	struct rb_root qgroup_tree;

	spinlock_t qgroup_lock;



	/*

	 * used to avoid frequently calling ulist_alloc()/ulist_free()

	 * when doing qgroup accounting, it must be protected by qgroup_lock.

	 */

	struct ulist *qgroup_ulist;



	/* protect user change for quota operations */

	struct mutex qgroup_ioctl_lock;

fs/btrfs/disk-io.c

+1 −0
Original line number Diff line number Diff line
@@ -2274,6 +2274,7 @@ int open_ctree(struct super_block *sb, 
	fs_info->qgroup_seq = 1;

	fs_info->quota_enabled = 0;

	fs_info->pending_quota_state = 0;

	fs_info->qgroup_ulist = NULL;

	mutex_init(&fs_info->qgroup_rescan_lock);



	btrfs_init_free_cluster(&fs_info->meta_alloc_cluster);

fs/btrfs/qgroup.c

+36 −34
Original line number Diff line number Diff line
@@ -259,6 +259,12 @@ int btrfs_read_qgroup_config(struct btrfs_fs_info *fs_info) 
	if (!fs_info->quota_enabled)

		return 0;



	fs_info->qgroup_ulist = ulist_alloc(GFP_NOFS);

	if (!fs_info->qgroup_ulist) {

		ret = -ENOMEM;

		goto out;

	}



	path = btrfs_alloc_path();

	if (!path) {

		ret = -ENOMEM;
@@ -424,6 +430,9 @@ out: 
	}

	btrfs_free_path(path);



	if (ret)

		ulist_free(fs_info->qgroup_ulist);



	return ret < 0 ? ret : 0;

}
@@ -460,6 +469,7 @@ void btrfs_free_qgroup_config(struct btrfs_fs_info *fs_info) 
		}

		kfree(qgroup);

	}

	ulist_free(fs_info->qgroup_ulist);

}



static int add_qgroup_relation_item(struct btrfs_trans_handle *trans,
@@ -819,6 +829,12 @@ int btrfs_quota_enable(struct btrfs_trans_handle *trans, 
		goto out;

	}



	fs_info->qgroup_ulist = ulist_alloc(GFP_NOFS);

	if (!fs_info->qgroup_ulist) {

		ret = -ENOMEM;

		goto out;

	}



	/*

	 * initially create the quota tree

	 */
@@ -916,6 +932,8 @@ out_free_root: 
		kfree(quota_root);

	}

out:

	if (ret)

		ulist_free(fs_info->qgroup_ulist);

	mutex_unlock(&fs_info->qgroup_ioctl_lock);

	return ret;

}
@@ -1355,7 +1373,6 @@ int btrfs_qgroup_account_ref(struct btrfs_trans_handle *trans, 
	u64 ref_root;

	struct btrfs_qgroup *qgroup;

	struct ulist *roots = NULL;

	struct ulist *tmp = NULL;

	u64 seq;

	int ret = 0;

	int sgn;
@@ -1448,31 +1465,28 @@ int btrfs_qgroup_account_ref(struct btrfs_trans_handle *trans, 
	/*

	 * step 1: for each old ref, visit all nodes once and inc refcnt

	 */

	tmp = ulist_alloc(GFP_ATOMIC);

	if (!tmp) {

		ret = -ENOMEM;

		goto unlock;

	}

	ulist_reinit(fs_info->qgroup_ulist);

	seq = fs_info->qgroup_seq;

	fs_info->qgroup_seq += roots->nnodes + 1; /* max refcnt */



	ret = qgroup_account_ref_step1(fs_info, roots, tmp, seq);

	ret = qgroup_account_ref_step1(fs_info, roots, fs_info->qgroup_ulist,

				       seq);

	if (ret)

		goto unlock;



	/*

	 * step 2: walk from the new root

	 */

	ret = qgroup_account_ref_step2(fs_info, roots, tmp, seq, sgn,

				       node->num_bytes, qgroup);

	ret = qgroup_account_ref_step2(fs_info, roots, fs_info->qgroup_ulist,

				       seq, sgn, node->num_bytes, qgroup);

	if (ret)

		goto unlock;



	/*

	 * step 3: walk again from old refs

	 */

	ret = qgroup_account_ref_step3(fs_info, roots, tmp, seq, sgn,

				       node->num_bytes);

	ret = qgroup_account_ref_step3(fs_info, roots, fs_info->qgroup_ulist,

				       seq, sgn, node->num_bytes);

	if (ret)

		goto unlock;
@@ -1480,7 +1494,6 @@ unlock: 
	spin_unlock(&fs_info->qgroup_lock);

	mutex_unlock(&fs_info->qgroup_rescan_lock);

	ulist_free(roots);

	ulist_free(tmp);



	return ret;

}
@@ -1720,7 +1733,6 @@ int btrfs_qgroup_reserve(struct btrfs_root *root, u64 num_bytes) 
	struct btrfs_fs_info *fs_info = root->fs_info;

	u64 ref_root = root->root_key.objectid;

	int ret = 0;

	struct ulist *ulist = NULL;

	struct ulist_node *unode;

	struct ulist_iterator uiter;
@@ -1743,17 +1755,13 @@ int btrfs_qgroup_reserve(struct btrfs_root *root, u64 num_bytes) 
	 * in a first step, we check all affected qgroups if any limits would

	 * be exceeded

	 */

	ulist = ulist_alloc(GFP_ATOMIC);

	if (!ulist) {

		ret = -ENOMEM;

		goto out;

	}

	ret = ulist_add(ulist, qgroup->qgroupid,

	ulist_reinit(fs_info->qgroup_ulist);

	ret = ulist_add(fs_info->qgroup_ulist, qgroup->qgroupid,

			(uintptr_t)qgroup, GFP_ATOMIC);

	if (ret < 0)

		goto out;

	ULIST_ITER_INIT(&uiter);

	while ((unode = ulist_next(ulist, &uiter))) {

	while ((unode = ulist_next(fs_info->qgroup_ulist, &uiter))) {

		struct btrfs_qgroup *qg;

		struct btrfs_qgroup_list *glist;
@@ -1774,7 +1782,8 @@ int btrfs_qgroup_reserve(struct btrfs_root *root, u64 num_bytes) 
		}



		list_for_each_entry(glist, &qg->groups, next_group) {

			ret = ulist_add(ulist, glist->group->qgroupid,

			ret = ulist_add(fs_info->qgroup_ulist,

					glist->group->qgroupid,

					(uintptr_t)glist->group, GFP_ATOMIC);

			if (ret < 0)

				goto out;
@@ -1785,7 +1794,7 @@ int btrfs_qgroup_reserve(struct btrfs_root *root, u64 num_bytes) 
	 * no limits exceeded, now record the reservation into all qgroups

	 */

	ULIST_ITER_INIT(&uiter);

	while ((unode = ulist_next(ulist, &uiter))) {

	while ((unode = ulist_next(fs_info->qgroup_ulist, &uiter))) {

		struct btrfs_qgroup *qg;



		qg = (struct btrfs_qgroup *)(uintptr_t)unode->aux;
@@ -1795,8 +1804,6 @@ int btrfs_qgroup_reserve(struct btrfs_root *root, u64 num_bytes) 


out:

	spin_unlock(&fs_info->qgroup_lock);

	ulist_free(ulist);



	return ret;

}
@@ -1805,7 +1812,6 @@ void btrfs_qgroup_free(struct btrfs_root *root, u64 num_bytes) 
	struct btrfs_root *quota_root;

	struct btrfs_qgroup *qgroup;

	struct btrfs_fs_info *fs_info = root->fs_info;

	struct ulist *ulist = NULL;

	struct ulist_node *unode;

	struct ulist_iterator uiter;

	u64 ref_root = root->root_key.objectid;
@@ -1827,17 +1833,13 @@ void btrfs_qgroup_free(struct btrfs_root *root, u64 num_bytes) 
	if (!qgroup)

		goto out;



	ulist = ulist_alloc(GFP_ATOMIC);

	if (!ulist) {

		btrfs_std_error(fs_info, -ENOMEM);

		goto out;

	}

	ret = ulist_add(ulist, qgroup->qgroupid,

	ulist_reinit(fs_info->qgroup_ulist);

	ret = ulist_add(fs_info->qgroup_ulist, qgroup->qgroupid,

			(uintptr_t)qgroup, GFP_ATOMIC);

	if (ret < 0)

		goto out;

	ULIST_ITER_INIT(&uiter);

	while ((unode = ulist_next(ulist, &uiter))) {

	while ((unode = ulist_next(fs_info->qgroup_ulist, &uiter))) {

		struct btrfs_qgroup *qg;

		struct btrfs_qgroup_list *glist;
@@ -1846,7 +1848,8 @@ void btrfs_qgroup_free(struct btrfs_root *root, u64 num_bytes) 
		qg->reserved -= num_bytes;



		list_for_each_entry(glist, &qg->groups, next_group) {

			ret = ulist_add(ulist, glist->group->qgroupid,

			ret = ulist_add(fs_info->qgroup_ulist,

					glist->group->qgroupid,

					(uintptr_t)glist->group, GFP_ATOMIC);

			if (ret < 0)

				goto out;
@@ -1855,7 +1858,6 @@ void btrfs_qgroup_free(struct btrfs_root *root, u64 num_bytes) 


out:

	spin_unlock(&fs_info->qgroup_lock);

	ulist_free(ulist);

}



void assert_qgroups_uptodate(struct btrfs_trans_handle *trans)

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