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Btrfs: introduce qgroup_ulist to avoid frequently allocating/freeing …
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…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: Wang Shilong <wangsl-fnst@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
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Wang Shilong authored and Josef Bacik committed Jun 14, 2013
1 parent 8596560 commit 1e8f915
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Showing 3 changed files with 43 additions and 34 deletions.
6 changes: 6 additions & 0 deletions fs/btrfs/ctree.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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;

Expand Down
1 change: 1 addition & 0 deletions fs/btrfs/disk-io.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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);
Expand Down
70 changes: 36 additions & 34 deletions fs/btrfs/qgroup.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand Down Expand Up @@ -424,6 +430,9 @@ int btrfs_read_qgroup_config(struct btrfs_fs_info *fs_info)
}
btrfs_free_path(path);

if (ret)
ulist_free(fs_info->qgroup_ulist);

return ret < 0 ? ret : 0;
}

Expand Down Expand Up @@ -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,
Expand Down Expand Up @@ -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
*/
Expand Down Expand Up @@ -916,6 +932,8 @@ int btrfs_quota_enable(struct btrfs_trans_handle *trans,
kfree(quota_root);
}
out:
if (ret)
ulist_free(fs_info->qgroup_ulist);
mutex_unlock(&fs_info->qgroup_ioctl_lock);
return ret;
}
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -1448,39 +1465,35 @@ 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;

unlock:
spin_unlock(&fs_info->qgroup_lock);
mutex_unlock(&fs_info->qgroup_rescan_lock);
ulist_free(roots);
ulist_free(tmp);

return ret;
}
Expand Down Expand Up @@ -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;

Expand All @@ -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;

Expand All @@ -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;
Expand All @@ -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;
Expand All @@ -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;
}

Expand All @@ -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;
Expand All @@ -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;

Expand All @@ -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;
Expand All @@ -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)
Expand Down

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