![Miao Xie](/assets/img/avatar_default.png)
Changelog V5 -> V6: - Fix oom when the memory load is high, by storing the delayed nodes into the root's radix tree, and letting btrfs inodes go. Changelog V4 -> V5: - Fix the race on adding the delayed node to the inode, which is spotted by Chris Mason. - Merge Chris Mason's incremental patch into this patch. - Fix deadlock between readdir() and memory fault, which is reported by Itaru Kitayama. Changelog V3 -> V4: - Fix nested lock, which is reported by Itaru Kitayama, by updating space cache inode in time. Changelog V2 -> V3: - Fix the race between the delayed worker and the task which does delayed items balance, which is reported by Tsutomu Itoh. - Modify the patch address David Sterba's comment. - Fix the bug of the cpu recursion spinlock, reported by Chris Mason Changelog V1 -> V2: - break up the global rb-tree, use a list to manage the delayed nodes, which is created for every directory and file, and used to manage the delayed directory name index items and the delayed inode item. - introduce a worker to deal with the delayed nodes. Compare with Ext3/4, the performance of file creation and deletion on btrfs is very poor. the reason is that btrfs must do a lot of b+ tree insertions, such as inode item, directory name item, directory name index and so on. If we can do some delayed b+ tree insertion or deletion, we can improve the performance, so we made this patch which implemented delayed directory name index insertion/deletion and delayed inode update. Implementation: - introduce a delayed root object into the filesystem, that use two lists to manage the delayed nodes which are created for every file/directory. One is used to manage all the delayed nodes that have delayed items. And the other is used to manage the delayed nodes which is waiting to be dealt with by the work thread. - Every delayed node has two rb-tree, one is used to manage the directory name index which is going to be inserted into b+ tree, and the other is used to manage the directory name index which is going to be deleted from b+ tree. - introduce a worker to deal with the delayed operation. This worker is used to deal with the works of the delayed directory name index items insertion and deletion and the delayed inode update. When the delayed items is beyond the lower limit, we create works for some delayed nodes and insert them into the work queue of the worker, and then go back. When the delayed items is beyond the upper bound, we create works for all the delayed nodes that haven't been dealt with, and insert them into the work queue of the worker, and then wait for that the untreated items is below some threshold value. - When we want to insert a directory name index into b+ tree, we just add the information into the delayed inserting rb-tree. And then we check the number of the delayed items and do delayed items balance. (The balance policy is above.) - When we want to delete a directory name index from the b+ tree, we search it in the inserting rb-tree at first. If we look it up, just drop it. If not, add the key of it into the delayed deleting rb-tree. Similar to the delayed inserting rb-tree, we also check the number of the delayed items and do delayed items balance. (The same to inserting manipulation) - When we want to update the metadata of some inode, we cached the data of the inode into the delayed node. the worker will flush it into the b+ tree after dealing with the delayed insertion and deletion. - We will move the delayed node to the tail of the list after we access the delayed node, By this way, we can cache more delayed items and merge more inode updates. - If we want to commit transaction, we will deal with all the delayed node. - the delayed node will be freed when we free the btrfs inode. - Before we log the inode items, we commit all the directory name index items and the delayed inode update. I did a quick test by the benchmark tool[1] and found we can improve the performance of file creation by ~15%, and file deletion by ~20%. Before applying this patch: Create files: Total files: 50000 Total time: 1.096108 Average time: 0.000022 Delete files: Total files: 50000 Total time: 1.510403 Average time: 0.000030 After applying this patch: Create files: Total files: 50000 Total time: 0.932899 Average time: 0.000019 Delete files: Total files: 50000 Total time: 1.215732 Average time: 0.000024 [1] http://marc.info/?l=linux-btrfs&m=128212635122920&q=p3 Many thanks for Kitayama-san's help! Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Reviewed-by: David Sterba <dave@jikos.cz> Tested-by: Tsutomu Itoh <t-itoh@jp.fujitsu.com> Tested-by: Itaru Kitayama <kitayama@cl.bb4u.ne.jp> Signed-off-by: Chris Mason <chris.mason@oracle.com>
134 lines
4.6 KiB
C
134 lines
4.6 KiB
C
/*
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* Copyright (C) 2007 Oracle. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public
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* License v2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public
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* License along with this program; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 021110-1307, USA.
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*/
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#ifndef __BTRFS_TRANSACTION__
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#define __BTRFS_TRANSACTION__
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#include "btrfs_inode.h"
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#include "delayed-ref.h"
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struct btrfs_transaction {
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u64 transid;
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/*
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* total writers in this transaction, it must be zero before the
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* transaction can end
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*/
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atomic_t num_writers;
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unsigned long num_joined;
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int in_commit;
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atomic_t use_count;
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int commit_done;
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int blocked;
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struct list_head list;
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struct extent_io_tree dirty_pages;
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unsigned long start_time;
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wait_queue_head_t writer_wait;
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wait_queue_head_t commit_wait;
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struct list_head pending_snapshots;
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struct btrfs_delayed_ref_root delayed_refs;
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};
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struct btrfs_trans_handle {
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u64 transid;
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u64 block_group;
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u64 bytes_reserved;
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unsigned long blocks_reserved;
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unsigned long blocks_used;
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unsigned long delayed_ref_updates;
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struct btrfs_transaction *transaction;
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struct btrfs_block_rsv *block_rsv;
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};
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struct btrfs_pending_snapshot {
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struct dentry *dentry;
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struct btrfs_root *root;
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struct btrfs_root *snap;
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/* block reservation for the operation */
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struct btrfs_block_rsv block_rsv;
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/* extra metadata reseration for relocation */
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int error;
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bool readonly;
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struct list_head list;
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};
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static inline void btrfs_set_trans_block_group(struct btrfs_trans_handle *trans,
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struct inode *inode)
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{
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trans->block_group = BTRFS_I(inode)->block_group;
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}
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static inline void btrfs_update_inode_block_group(
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struct btrfs_trans_handle *trans,
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struct inode *inode)
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{
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BTRFS_I(inode)->block_group = trans->block_group;
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}
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static inline void btrfs_set_inode_last_trans(struct btrfs_trans_handle *trans,
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struct inode *inode)
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{
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BTRFS_I(inode)->last_trans = trans->transaction->transid;
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BTRFS_I(inode)->last_sub_trans = BTRFS_I(inode)->root->log_transid;
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}
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int btrfs_end_transaction(struct btrfs_trans_handle *trans,
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struct btrfs_root *root);
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int btrfs_end_transaction_nolock(struct btrfs_trans_handle *trans,
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struct btrfs_root *root);
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struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
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int num_items);
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struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root,
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int num_blocks);
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struct btrfs_trans_handle *btrfs_join_transaction_nolock(struct btrfs_root *root,
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int num_blocks);
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struct btrfs_trans_handle *btrfs_start_ioctl_transaction(struct btrfs_root *r,
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int num_blocks);
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int btrfs_wait_for_commit(struct btrfs_root *root, u64 transid);
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int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans,
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struct btrfs_root *root);
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int btrfs_commit_tree_roots(struct btrfs_trans_handle *trans,
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struct btrfs_root *root);
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int btrfs_add_dead_root(struct btrfs_root *root);
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int btrfs_drop_dead_root(struct btrfs_root *root);
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int btrfs_defrag_root(struct btrfs_root *root, int cacheonly);
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int btrfs_clean_old_snapshots(struct btrfs_root *root);
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int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
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struct btrfs_root *root);
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int btrfs_commit_transaction_async(struct btrfs_trans_handle *trans,
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struct btrfs_root *root,
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int wait_for_unblock);
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int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans,
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struct btrfs_root *root);
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int btrfs_end_transaction_dmeta(struct btrfs_trans_handle *trans,
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struct btrfs_root *root);
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int btrfs_should_end_transaction(struct btrfs_trans_handle *trans,
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struct btrfs_root *root);
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void btrfs_throttle(struct btrfs_root *root);
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int btrfs_record_root_in_trans(struct btrfs_trans_handle *trans,
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struct btrfs_root *root);
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int btrfs_write_and_wait_marked_extents(struct btrfs_root *root,
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struct extent_io_tree *dirty_pages, int mark);
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int btrfs_write_marked_extents(struct btrfs_root *root,
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struct extent_io_tree *dirty_pages, int mark);
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int btrfs_wait_marked_extents(struct btrfs_root *root,
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struct extent_io_tree *dirty_pages, int mark);
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int btrfs_transaction_blocked(struct btrfs_fs_info *info);
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int btrfs_transaction_in_commit(struct btrfs_fs_info *info);
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#endif
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