Miao Xie
2013-Jan-10 12:49 UTC
[PATCH 07/11] Btrfs: use percpu counter for fs_info->delalloc_bytes
fs_info->delalloc_bytes is accessed very frequently, so use percpu counter
instead of the u64 variant for it to reduce the lock contention.
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
---
fs/btrfs/ctree.h | 7 ++++---
fs/btrfs/disk-io.c | 18 ++++++++++++++----
fs/btrfs/extent-tree.c | 6 ++++--
fs/btrfs/inode.c | 6 ++++--
4 files changed, 26 insertions(+), 11 deletions(-)
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 1dcbbfd..51515a3 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1383,6 +1383,7 @@ struct btrfs_fs_info {
*/
struct list_head ordered_extents;
+ spinlock_t delalloc_lock;
/*
* all of the inodes that have delalloc bytes. It is possible for
* this list to be empty even when there is still dirty data=ordered
@@ -1443,7 +1444,10 @@ struct btrfs_fs_info {
/* used to keep from writing metadata until there is a nice batch */
struct percpu_counter dirty_metadata_bytes;
+ struct percpu_counter delalloc_bytes;
s32 dirty_metadata_batch;
+ s32 delalloc_batch;
+
struct list_head dirty_cowonly_roots;
struct btrfs_fs_devices *fs_devices;
@@ -1459,9 +1463,6 @@ struct btrfs_fs_info {
struct reloc_control *reloc_ctl;
- spinlock_t delalloc_lock;
- u64 delalloc_bytes;
-
/* data_alloc_cluster is only used in ssd mode */
struct btrfs_free_cluster data_alloc_cluster;
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index adf270e..750afd4 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -2006,10 +2006,16 @@ int open_ctree(struct super_block *sb,
fs_info->dirty_metadata_batch = PAGE_CACHE_SIZE *
(1 + ilog2(nr_cpu_ids));
+ ret = percpu_counter_init(&fs_info->delalloc_bytes, 0);
+ if (ret) {
+ err = ret;
+ goto fail_dirty_metadata_bytes;
+ }
+
fs_info->btree_inode = new_inode(sb);
if (!fs_info->btree_inode) {
err = -ENOMEM;
- goto fail_dirty_metadata_bytes;
+ goto fail_delalloc_bytes;
}
mapping_set_gfp_mask(fs_info->btree_inode->i_mapping, GFP_NOFS);
@@ -2264,6 +2270,7 @@ int open_ctree(struct super_block *sb,
sectorsize = btrfs_super_sectorsize(disk_super);
stripesize = btrfs_super_stripesize(disk_super);
fs_info->dirty_metadata_batch = leafsize * (1 + ilog2(nr_cpu_ids));
+ fs_info->delalloc_batch = sectorsize * 512 * (1 + ilog2(nr_cpu_ids));
/*
* mixed block groups end up with duplicate but slightly offset
@@ -2726,6 +2733,8 @@ fail_iput:
invalidate_inode_pages2(fs_info->btree_inode->i_mapping);
iput(fs_info->btree_inode);
+fail_delalloc_bytes:
+ percpu_counter_destroy(&fs_info->delalloc_bytes);
fail_dirty_metadata_bytes:
percpu_counter_destroy(&fs_info->dirty_metadata_bytes);
fail_bdi:
@@ -3357,9 +3366,9 @@ int close_ctree(struct btrfs_root *root)
btrfs_free_qgroup_config(root->fs_info);
- if (fs_info->delalloc_bytes) {
- printk(KERN_INFO "btrfs: at unmount delalloc count %llu\n",
- (unsigned long long)fs_info->delalloc_bytes);
+ if (percpu_counter_sum(&fs_info->delalloc_bytes)) {
+ printk(KERN_INFO "btrfs: at unmount delalloc count %lld\n",
+ percpu_counter_sum(&fs_info->delalloc_bytes));
}
free_extent_buffer(fs_info->extent_root->node);
@@ -3407,6 +3416,7 @@ int close_ctree(struct btrfs_root *root)
btrfs_mapping_tree_free(&fs_info->mapping_tree);
percpu_counter_destroy(&fs_info->dirty_metadata_bytes);
+ percpu_counter_destroy(&fs_info->delalloc_bytes);
bdi_destroy(&fs_info->bdi);
cleanup_srcu_struct(&fs_info->subvol_srcu);
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index a302e3a..2ec978b1 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -3755,7 +3755,8 @@ static void shrink_delalloc(struct btrfs_root *root, u64
to_reclaim, u64 orig,
space_info = block_rsv->space_info;
smp_mb();
- delalloc_bytes = root->fs_info->delalloc_bytes;
+ delalloc_bytes = percpu_counter_sum_positive(
+ &root->fs_info->delalloc_bytes);
if (delalloc_bytes == 0) {
if (trans)
return;
@@ -3794,7 +3795,8 @@ static void shrink_delalloc(struct btrfs_root *root, u64
to_reclaim, u64 orig,
break;
}
smp_mb();
- delalloc_bytes = root->fs_info->delalloc_bytes;
+ delalloc_bytes = percpu_counter_sum_positive(
+ &root->fs_info->delalloc_bytes);
}
}
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index fb70bcb..c29299d 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -1510,7 +1510,8 @@ static void btrfs_set_bit_hook(struct inode *inode,
spin_lock(&root->fs_info->delalloc_lock);
BTRFS_I(inode)->delalloc_bytes += len;
- root->fs_info->delalloc_bytes += len;
+ __percpu_counter_add(&root->fs_info->delalloc_bytes, len,
+ root->fs_info->delalloc_batch);
if (do_list && list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
list_add_tail(&BTRFS_I(inode)->delalloc_inodes,
&root->fs_info->delalloc_inodes);
@@ -1551,7 +1552,8 @@ static void btrfs_clear_bit_hook(struct inode *inode,
btrfs_free_reserved_data_space(inode, len);
spin_lock(&root->fs_info->delalloc_lock);
- root->fs_info->delalloc_bytes -= len;
+ __percpu_counter_add(&root->fs_info->delalloc_bytes, -len,
+ root->fs_info->delalloc_batch);
BTRFS_I(inode)->delalloc_bytes -= len;
if (do_list && BTRFS_I(inode)->delalloc_bytes == 0 &&
--
1.7.11.7
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