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Commit 4aeb664c authored by Nathan Scott's avatar Nathan Scott
Browse files

[XFS] Improve buffered read throughput by removing unnecessary timer calls


that showed in ´kernel profiles.

SGI-PV: 925163
SGI-Modid: xfs-linux:xfs-kern:23861a

Signed-off-by: default avatarNathan Scott <nathans@sgi.com>
parent 0fdfb375
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+131 −0
Original line number Diff line number Diff line
@@ -69,6 +69,137 @@
#include <linux/xattr.h>
#include <linux/namei.h>

/*
 * Change the requested timestamp in the given inode.
 * We don't lock across timestamp updates, and we don't log them but
 * we do record the fact that there is dirty information in core.
 *
 * NOTE -- callers MUST combine XFS_ICHGTIME_MOD or XFS_ICHGTIME_CHG
 *		with XFS_ICHGTIME_ACC to be sure that access time
 *		update will take.  Calling first with XFS_ICHGTIME_ACC
 *		and then XFS_ICHGTIME_MOD may fail to modify the access
 *		timestamp if the filesystem is mounted noacctm.
 */
void
xfs_ichgtime(
	xfs_inode_t	*ip,
	int		flags)
{
	struct inode	*inode = LINVFS_GET_IP(XFS_ITOV(ip));
	timespec_t	tv;

	/*
	 * We're not supposed to change timestamps in readonly-mounted
	 * filesystems.  Throw it away if anyone asks us.
	 */
	if (unlikely(IS_RDONLY(inode)))
		return;

	/*
	 * Don't update access timestamps on reads if mounted "noatime".
	 * Throw it away if anyone asks us.
	 */
	if (unlikely(
	    (ip->i_mount->m_flags & XFS_MOUNT_NOATIME || IS_NOATIME(inode)) &&
	    (flags & (XFS_ICHGTIME_ACC|XFS_ICHGTIME_MOD|XFS_ICHGTIME_CHG)) ==
			XFS_ICHGTIME_ACC))
		return;

	nanotime(&tv);
	if (flags & XFS_ICHGTIME_MOD) {
		inode->i_mtime = tv;
		ip->i_d.di_mtime.t_sec = (__int32_t)tv.tv_sec;
		ip->i_d.di_mtime.t_nsec = (__int32_t)tv.tv_nsec;
	}
	if (flags & XFS_ICHGTIME_ACC) {
		inode->i_atime = tv;
		ip->i_d.di_atime.t_sec = (__int32_t)tv.tv_sec;
		ip->i_d.di_atime.t_nsec = (__int32_t)tv.tv_nsec;
	}
	if (flags & XFS_ICHGTIME_CHG) {
		inode->i_ctime = tv;
		ip->i_d.di_ctime.t_sec = (__int32_t)tv.tv_sec;
		ip->i_d.di_ctime.t_nsec = (__int32_t)tv.tv_nsec;
	}

	/*
	 * We update the i_update_core field _after_ changing
	 * the timestamps in order to coordinate properly with
	 * xfs_iflush() so that we don't lose timestamp updates.
	 * This keeps us from having to hold the inode lock
	 * while doing this.  We use the SYNCHRONIZE macro to
	 * ensure that the compiler does not reorder the update
	 * of i_update_core above the timestamp updates above.
	 */
	SYNCHRONIZE();
	ip->i_update_core = 1;
	if (!(inode->i_state & I_LOCK))
		mark_inode_dirty_sync(inode);
}

/*
 * Variant on the above which avoids querying the system clock
 * in situations where we know the Linux inode timestamps have
 * just been updated (and so we can update our inode cheaply).
 * We also skip the readonly and noatime checks here, they are
 * also catered for already.
 */
void
xfs_ichgtime_fast(
	xfs_inode_t	*ip,
	struct inode	*inode,
	int		flags)
{
	timespec_t	*tvp;

	/*
	 * We're not supposed to change timestamps in readonly-mounted
	 * filesystems.  Throw it away if anyone asks us.
	 */
	if (unlikely(IS_RDONLY(inode)))
		return;

	/*
	 * Don't update access timestamps on reads if mounted "noatime".
	 * Throw it away if anyone asks us.
	 */
	if (unlikely(
	    (ip->i_mount->m_flags & XFS_MOUNT_NOATIME || IS_NOATIME(inode)) &&
	    ((flags & (XFS_ICHGTIME_ACC|XFS_ICHGTIME_MOD|XFS_ICHGTIME_CHG)) ==
			XFS_ICHGTIME_ACC)))
		return;

	if (flags & XFS_ICHGTIME_MOD) {
		tvp = &inode->i_mtime;
		ip->i_d.di_mtime.t_sec = (__int32_t)tvp->tv_sec;
		ip->i_d.di_mtime.t_nsec = (__int32_t)tvp->tv_nsec;
	}
	if (flags & XFS_ICHGTIME_ACC) {
		tvp = &inode->i_atime;
		ip->i_d.di_atime.t_sec = (__int32_t)tvp->tv_sec;
		ip->i_d.di_atime.t_nsec = (__int32_t)tvp->tv_nsec;
	}
	if (flags & XFS_ICHGTIME_CHG) {
		tvp = &inode->i_ctime;
		ip->i_d.di_ctime.t_sec = (__int32_t)tvp->tv_sec;
		ip->i_d.di_ctime.t_nsec = (__int32_t)tvp->tv_nsec;
	}

	/*
	 * We update the i_update_core field _after_ changing
	 * the timestamps in order to coordinate properly with
	 * xfs_iflush() so that we don't lose timestamp updates.
	 * This keeps us from having to hold the inode lock
	 * while doing this.  We use the SYNCHRONIZE macro to
	 * ensure that the compiler does not reorder the update
	 * of i_update_core above the timestamp updates above.
	 */
	SYNCHRONIZE();
	ip->i_update_core = 1;
	if (!(inode->i_state & I_LOCK))
		mark_inode_dirty_sync(inode);
}


/*
 * Pull the link count and size up from the xfs inode to the linux inode
+4 −0
Original line number Diff line number Diff line
@@ -48,4 +48,8 @@ extern void linvfs_unwritten_done(struct buffer_head *, int);
extern int xfs_ioctl(struct bhv_desc *, struct inode *, struct file *,
                        int, unsigned int, void __user *);

struct xfs_inode;
extern void xfs_ichgtime(struct xfs_inode *, int);
extern void xfs_ichgtime_fast(struct xfs_inode *, struct inode *, int);

#endif /* __XFS_IOPS_H__ */
+5 −10
Original line number Diff line number Diff line
@@ -302,7 +302,7 @@ xfs_read(
	xfs_iunlock(ip, XFS_IOLOCK_SHARED);

	if (likely(!(ioflags & IO_INVIS)))
		xfs_ichgtime(ip, XFS_ICHGTIME_ACC);
		xfs_ichgtime_fast(ip, inode, XFS_ICHGTIME_ACC);

unlock_isem:
	if (unlikely(ioflags & IO_ISDIRECT))
@@ -367,7 +367,7 @@ xfs_sendfile(
		XFS_STATS_ADD(xs_read_bytes, ret);

	if (likely(!(ioflags & IO_INVIS)))
		xfs_ichgtime(ip, XFS_ICHGTIME_ACC);
		xfs_ichgtime_fast(ip, LINVFS_GET_IP(vp), XFS_ICHGTIME_ACC);

	return ret;
}
@@ -732,15 +732,10 @@ xfs_write(
		}
	}

	/*
	 * On Linux, generic_file_write updates the times even if
	 * no data is copied in so long as the write had a size.
	 *
	 * We must update xfs' times since revalidate will overcopy xfs.
	 */
	if (!(ioflags & IO_INVIS)) {
		xfs_ichgtime(xip, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
	if (likely(!(ioflags & IO_INVIS))) {
		inode_update_time(inode, 1);
		xfs_ichgtime_fast(xip, inode,
				  XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
	}

	/*
+0 −7
Original line number Diff line number Diff line
@@ -566,13 +566,6 @@ static __inline__ void vn_flagclr(struct vnode *vp, uint flag)
	spin_unlock(&vp->v_lock);
}

/*
 * Update modify/access/change times on the vnode
 */
#define VN_MTIMESET(vp, tvp)	(LINVFS_GET_IP(vp)->i_mtime = *(tvp))
#define VN_ATIMESET(vp, tvp)	(LINVFS_GET_IP(vp)->i_atime = *(tvp))
#define VN_CTIMESET(vp, tvp)	(LINVFS_GET_IP(vp)->i_ctime = *(tvp))

/*
 * Dealing with bad inodes
 */
+0 −67
Original line number Diff line number Diff line
@@ -3688,73 +3688,6 @@ xfs_iroundup(
	return( 0 );
}

/*
 * Change the requested timestamp in the given inode.
 * We don't lock across timestamp updates, and we don't log them but
 * we do record the fact that there is dirty information in core.
 *
 * NOTE -- callers MUST combine XFS_ICHGTIME_MOD or XFS_ICHGTIME_CHG
 *		with XFS_ICHGTIME_ACC to be sure that access time
 *		update will take.  Calling first with XFS_ICHGTIME_ACC
 *		and then XFS_ICHGTIME_MOD may fail to modify the access
 *		timestamp if the filesystem is mounted noacctm.
 */
void
xfs_ichgtime(xfs_inode_t *ip,
	     int flags)
{
	timespec_t	tv;
	vnode_t		*vp = XFS_ITOV(ip);
	struct inode	*inode = LINVFS_GET_IP(vp);

	/*
	 * We're not supposed to change timestamps in readonly-mounted
	 * filesystems.  Throw it away if anyone asks us.
	 */
	if (unlikely(vp->v_vfsp->vfs_flag & VFS_RDONLY))
		return;

	/*
	 * Don't update access timestamps on reads if mounted "noatime"
	 * Throw it away if anyone asks us.
	 */
	if ((ip->i_mount->m_flags & XFS_MOUNT_NOATIME || IS_NOATIME(inode)) &&
	    ((flags & (XFS_ICHGTIME_ACC|XFS_ICHGTIME_MOD|XFS_ICHGTIME_CHG))
			== XFS_ICHGTIME_ACC))
		return;

	nanotime(&tv);
	if (flags & XFS_ICHGTIME_MOD) {
		VN_MTIMESET(vp, &tv);
		ip->i_d.di_mtime.t_sec = (__int32_t)tv.tv_sec;
		ip->i_d.di_mtime.t_nsec = (__int32_t)tv.tv_nsec;
	}
	if (flags & XFS_ICHGTIME_ACC) {
		VN_ATIMESET(vp, &tv);
		ip->i_d.di_atime.t_sec = (__int32_t)tv.tv_sec;
		ip->i_d.di_atime.t_nsec = (__int32_t)tv.tv_nsec;
	}
	if (flags & XFS_ICHGTIME_CHG) {
		VN_CTIMESET(vp, &tv);
		ip->i_d.di_ctime.t_sec = (__int32_t)tv.tv_sec;
		ip->i_d.di_ctime.t_nsec = (__int32_t)tv.tv_nsec;
	}

	/*
	 * We update the i_update_core field _after_ changing
	 * the timestamps in order to coordinate properly with
	 * xfs_iflush() so that we don't lose timestamp updates.
	 * This keeps us from having to hold the inode lock
	 * while doing this.  We use the SYNCHRONIZE macro to
	 * ensure that the compiler does not reorder the update
	 * of i_update_core above the timestamp updates above.
	 */
	SYNCHRONIZE();
	ip->i_update_core = 1;
	if (!(inode->i_state & I_LOCK))
		mark_inode_dirty_sync(inode);
}

#ifdef XFS_ILOCK_TRACE
ktrace_t	*xfs_ilock_trace_buf;