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linux-2.6/fs/xfs/xfs_trans_inode.c
Dave Chinner dcd79a1423 xfs: don't use vfs writeback for pure metadata modifications
Under heavy multi-way parallel create workloads, the VFS struggles
to write back all the inodes that have been changed in age order.
The bdi flusher thread becomes CPU bound, spending 85% of it's time
in the VFS code, mostly traversing the superblock dirty inode list
to separate dirty inodes old enough to flush.

We already keep an index of all metadata changes in age order - in
the AIL - and continued log pressure will do age ordered writeback
without any extra overhead at all. If there is no pressure on the
log, the xfssyncd will periodically write back metadata in ascending
disk address offset order so will be very efficient.

Hence we can stop marking VFS inodes dirty during transaction commit
or when changing timestamps during transactions. This will keep the
inodes in the superblock dirty list to those containing data or
unlogged metadata changes.

However, the timstamp changes are slightly more complex than this -
there are a couple of places that do unlogged updates of the
timestamps, and the VFS need to be informed of these. Hence add a
new function xfs_trans_ichgtime() for transactional changes,
and leave xfs_ichgtime() for the non-transactional changes.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Alex Elder <aelder@sgi.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2010-10-18 15:07:45 -05:00

213 lines
5.3 KiB
C

/*
* Copyright (c) 2000,2005 Silicon Graphics, Inc.
* 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 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it would 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 the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_types.h"
#include "xfs_bit.h"
#include "xfs_log.h"
#include "xfs_inum.h"
#include "xfs_trans.h"
#include "xfs_sb.h"
#include "xfs_ag.h"
#include "xfs_mount.h"
#include "xfs_bmap_btree.h"
#include "xfs_alloc_btree.h"
#include "xfs_ialloc_btree.h"
#include "xfs_dinode.h"
#include "xfs_inode.h"
#include "xfs_btree.h"
#include "xfs_trans_priv.h"
#include "xfs_inode_item.h"
#include "xfs_trace.h"
#ifdef XFS_TRANS_DEBUG
STATIC void
xfs_trans_inode_broot_debug(
xfs_inode_t *ip);
#else
#define xfs_trans_inode_broot_debug(ip)
#endif
/*
* Get an inode and join it to the transaction.
*/
int
xfs_trans_iget(
xfs_mount_t *mp,
xfs_trans_t *tp,
xfs_ino_t ino,
uint flags,
uint lock_flags,
xfs_inode_t **ipp)
{
int error;
error = xfs_iget(mp, tp, ino, flags, lock_flags, ipp);
if (!error && tp) {
xfs_trans_ijoin(tp, *ipp);
(*ipp)->i_itemp->ili_lock_flags = lock_flags;
}
return error;
}
/*
* Add a locked inode to the transaction.
*
* The inode must be locked, and it cannot be associated with any transaction.
*/
void
xfs_trans_ijoin(
struct xfs_trans *tp,
struct xfs_inode *ip)
{
xfs_inode_log_item_t *iip;
ASSERT(ip->i_transp == NULL);
ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
if (ip->i_itemp == NULL)
xfs_inode_item_init(ip, ip->i_mount);
iip = ip->i_itemp;
ASSERT(iip->ili_lock_flags == 0);
/*
* Get a log_item_desc to point at the new item.
*/
xfs_trans_add_item(tp, &iip->ili_item);
xfs_trans_inode_broot_debug(ip);
/*
* Initialize i_transp so we can find it with xfs_inode_incore()
* in xfs_trans_iget() above.
*/
ip->i_transp = tp;
}
/*
* Add a locked inode to the transaction.
*
*
* Grabs a reference to the inode which will be dropped when the transaction
* is commited. The inode will also be unlocked at that point. The inode
* must be locked, and it cannot be associated with any transaction.
*/
void
xfs_trans_ijoin_ref(
struct xfs_trans *tp,
struct xfs_inode *ip,
uint lock_flags)
{
xfs_trans_ijoin(tp, ip);
IHOLD(ip);
ip->i_itemp->ili_lock_flags = lock_flags;
}
/*
* Transactional inode timestamp update. Requires the inode to be locked and
* joined to the transaction supplied. Relies on the transaction subsystem to
* track dirty state and update/writeback the inode accordingly.
*/
void
xfs_trans_ichgtime(
struct xfs_trans *tp,
struct xfs_inode *ip,
int flags)
{
struct inode *inode = VFS_I(ip);
timespec_t tv;
ASSERT(tp);
ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
ASSERT(ip->i_transp == tp);
tv = current_fs_time(inode->i_sb);
if ((flags & XFS_ICHGTIME_MOD) &&
!timespec_equal(&inode->i_mtime, &tv)) {
inode->i_mtime = tv;
}
if ((flags & XFS_ICHGTIME_CHG) &&
!timespec_equal(&inode->i_ctime, &tv)) {
inode->i_ctime = tv;
}
}
/*
* This is called to mark the fields indicated in fieldmask as needing
* to be logged when the transaction is committed. The inode must
* already be associated with the given transaction.
*
* The values for fieldmask are defined in xfs_inode_item.h. We always
* log all of the core inode if any of it has changed, and we always log
* all of the inline data/extents/b-tree root if any of them has changed.
*/
void
xfs_trans_log_inode(
xfs_trans_t *tp,
xfs_inode_t *ip,
uint flags)
{
ASSERT(ip->i_transp == tp);
ASSERT(ip->i_itemp != NULL);
ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
tp->t_flags |= XFS_TRANS_DIRTY;
ip->i_itemp->ili_item.li_desc->lid_flags |= XFS_LID_DIRTY;
/*
* Always OR in the bits from the ili_last_fields field.
* This is to coordinate with the xfs_iflush() and xfs_iflush_done()
* routines in the eventual clearing of the ilf_fields bits.
* See the big comment in xfs_iflush() for an explanation of
* this coordination mechanism.
*/
flags |= ip->i_itemp->ili_last_fields;
ip->i_itemp->ili_format.ilf_fields |= flags;
}
#ifdef XFS_TRANS_DEBUG
/*
* Keep track of the state of the inode btree root to make sure we
* log it properly.
*/
STATIC void
xfs_trans_inode_broot_debug(
xfs_inode_t *ip)
{
xfs_inode_log_item_t *iip;
ASSERT(ip->i_itemp != NULL);
iip = ip->i_itemp;
if (iip->ili_root_size != 0) {
ASSERT(iip->ili_orig_root != NULL);
kmem_free(iip->ili_orig_root);
iip->ili_root_size = 0;
iip->ili_orig_root = NULL;
}
if (ip->i_d.di_format == XFS_DINODE_FMT_BTREE) {
ASSERT((ip->i_df.if_broot != NULL) &&
(ip->i_df.if_broot_bytes > 0));
iip->ili_root_size = ip->i_df.if_broot_bytes;
iip->ili_orig_root =
(char*)kmem_alloc(iip->ili_root_size, KM_SLEEP);
memcpy(iip->ili_orig_root, (char*)(ip->i_df.if_broot),
iip->ili_root_size);
}
}
#endif