linux/fs/btrfs/qgroup.h
Qu Wenruo fb235dc06f btrfs: qgroup: Move half of the qgroup accounting time out of commit trans
Just as Filipe pointed out, the most time consuming parts of qgroup are
btrfs_qgroup_account_extents() and
btrfs_qgroup_prepare_account_extents().
Which both call btrfs_find_all_roots() to get old_roots and new_roots
ulist.

What makes things worse is, we're calling that expensive
btrfs_find_all_roots() at transaction committing time with
TRANS_STATE_COMMIT_DOING, which will blocks all incoming transaction.

Such behavior is necessary for @new_roots search as current
btrfs_find_all_roots() can't do it correctly so we do call it just
before switch commit roots.

However for @old_roots search, it's not necessary as such search is
based on commit_root, so it will always be correct and we can move it
out of transaction committing.

This patch moves the @old_roots search part out of
commit_transaction(), so in theory we can half the time qgroup time
consumption at commit_transaction().

But please note that, this won't speedup qgroup overall, the total time
consumption is still the same, just reduce the performance stall.

Cc: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2017-02-17 12:03:55 +01:00

217 lines
7.8 KiB
C

/*
* Copyright (C) 2014 Facebook. All rights reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public
* License v2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public
* License along with this program; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 021110-1307, USA.
*/
#ifndef __BTRFS_QGROUP__
#define __BTRFS_QGROUP__
#include "ulist.h"
#include "delayed-ref.h"
/*
* Btrfs qgroup overview
*
* Btrfs qgroup splits into 3 main part:
* 1) Reserve
* Reserve metadata/data space for incoming operations
* Affect how qgroup limit works
*
* 2) Trace
* Tell btrfs qgroup to trace dirty extents.
*
* Dirty extents including:
* - Newly allocated extents
* - Extents going to be deleted (in this trans)
* - Extents whose owner is going to be modified
*
* This is the main part affects whether qgroup numbers will stay
* consistent.
* Btrfs qgroup can trace clean extents and won't cause any problem,
* but it will consume extra CPU time, it should be avoided if possible.
*
* 3) Account
* Btrfs qgroup will updates its numbers, based on dirty extents traced
* in previous step.
*
* Normally at qgroup rescan and transaction commit time.
*/
/*
* Record a dirty extent, and info qgroup to update quota on it
* TODO: Use kmem cache to alloc it.
*/
struct btrfs_qgroup_extent_record {
struct rb_node node;
u64 bytenr;
u64 num_bytes;
struct ulist *old_roots;
};
/*
* For qgroup event trace points only
*/
#define QGROUP_RESERVE (1<<0)
#define QGROUP_RELEASE (1<<1)
#define QGROUP_FREE (1<<2)
int btrfs_quota_enable(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info);
int btrfs_quota_disable(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info);
int btrfs_qgroup_rescan(struct btrfs_fs_info *fs_info);
void btrfs_qgroup_rescan_resume(struct btrfs_fs_info *fs_info);
int btrfs_qgroup_wait_for_completion(struct btrfs_fs_info *fs_info,
bool interruptible);
int btrfs_add_qgroup_relation(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info, u64 src, u64 dst);
int btrfs_del_qgroup_relation(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info, u64 src, u64 dst);
int btrfs_create_qgroup(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info, u64 qgroupid);
int btrfs_remove_qgroup(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info, u64 qgroupid);
int btrfs_limit_qgroup(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info, u64 qgroupid,
struct btrfs_qgroup_limit *limit);
int btrfs_read_qgroup_config(struct btrfs_fs_info *fs_info);
void btrfs_free_qgroup_config(struct btrfs_fs_info *fs_info);
struct btrfs_delayed_extent_op;
int btrfs_qgroup_prepare_account_extents(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info);
/*
* Inform qgroup to trace one dirty extent, its info is recorded in @record.
* So qgroup can account it at transaction committing time.
*
* No lock version, caller must acquire delayed ref lock and allocated memory,
* then call btrfs_qgroup_trace_extent_post() after exiting lock context.
*
* Return 0 for success insert
* Return >0 for existing record, caller can free @record safely.
* Error is not possible
*/
int btrfs_qgroup_trace_extent_nolock(
struct btrfs_fs_info *fs_info,
struct btrfs_delayed_ref_root *delayed_refs,
struct btrfs_qgroup_extent_record *record);
/*
* Post handler after qgroup_trace_extent_nolock().
*
* NOTE: Current qgroup does the expensive backref walk at transaction
* committing time with TRANS_STATE_COMMIT_DOING, this blocks incoming
* new transaction.
* This is designed to allow btrfs_find_all_roots() to get correct new_roots
* result.
*
* However for old_roots there is no need to do backref walk at that time,
* since we search commit roots to walk backref and result will always be
* correct.
*
* Due to the nature of no lock version, we can't do backref there.
* So we must call btrfs_qgroup_trace_extent_post() after exiting
* spinlock context.
*
* TODO: If we can fix and prove btrfs_find_all_roots() can get correct result
* using current root, then we can move all expensive backref walk out of
* transaction committing, but not now as qgroup accounting will be wrong again.
*/
int btrfs_qgroup_trace_extent_post(struct btrfs_fs_info *fs_info,
struct btrfs_qgroup_extent_record *qrecord);
/*
* Inform qgroup to trace one dirty extent, specified by @bytenr and
* @num_bytes.
* So qgroup can account it at commit trans time.
*
* Better encapsulated version, with memory allocation and backref walk for
* commit roots.
* So this can sleep.
*
* Return 0 if the operation is done.
* Return <0 for error, like memory allocation failure or invalid parameter
* (NULL trans)
*/
int btrfs_qgroup_trace_extent(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info, u64 bytenr, u64 num_bytes,
gfp_t gfp_flag);
/*
* Inform qgroup to trace all leaf items of data
*
* Return 0 for success
* Return <0 for error(ENOMEM)
*/
int btrfs_qgroup_trace_leaf_items(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info,
struct extent_buffer *eb);
/*
* Inform qgroup to trace a whole subtree, including all its child tree
* blocks and data.
* The root tree block is specified by @root_eb.
*
* Normally used by relocation(tree block swap) and subvolume deletion.
*
* Return 0 for success
* Return <0 for error(ENOMEM or tree search error)
*/
int btrfs_qgroup_trace_subtree(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct extent_buffer *root_eb,
u64 root_gen, int root_level);
int
btrfs_qgroup_account_extent(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info,
u64 bytenr, u64 num_bytes,
struct ulist *old_roots, struct ulist *new_roots);
int btrfs_qgroup_account_extents(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info);
int btrfs_run_qgroups(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info);
int btrfs_qgroup_inherit(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info, u64 srcid, u64 objectid,
struct btrfs_qgroup_inherit *inherit);
void btrfs_qgroup_free_refroot(struct btrfs_fs_info *fs_info,
u64 ref_root, u64 num_bytes);
/*
* TODO: Add proper trace point for it, as btrfs_qgroup_free() is
* called by everywhere, can't provide good trace for delayed ref case.
*/
static inline void btrfs_qgroup_free_delayed_ref(struct btrfs_fs_info *fs_info,
u64 ref_root, u64 num_bytes)
{
btrfs_qgroup_free_refroot(fs_info, ref_root, num_bytes);
trace_btrfs_qgroup_free_delayed_ref(fs_info, ref_root, num_bytes);
}
void assert_qgroups_uptodate(struct btrfs_trans_handle *trans);
#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
int btrfs_verify_qgroup_counts(struct btrfs_fs_info *fs_info, u64 qgroupid,
u64 rfer, u64 excl);
#endif
/* New io_tree based accurate qgroup reserve API */
int btrfs_qgroup_reserve_data(struct inode *inode, u64 start, u64 len);
int btrfs_qgroup_release_data(struct inode *inode, u64 start, u64 len);
int btrfs_qgroup_free_data(struct inode *inode, u64 start, u64 len);
int btrfs_qgroup_reserve_meta(struct btrfs_root *root, int num_bytes,
bool enforce);
void btrfs_qgroup_free_meta_all(struct btrfs_root *root);
void btrfs_qgroup_free_meta(struct btrfs_root *root, int num_bytes);
void btrfs_qgroup_check_reserved_leak(struct inode *inode);
#endif /* __BTRFS_QGROUP__ */