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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

fs/xfs/linux-2.6/xfs_iops.c

+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

fs/xfs/linux-2.6/xfs_iops.h

+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__ */

fs/xfs/linux-2.6/xfs_lrw.c

+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);

	}



	/*

fs/xfs/linux-2.6/xfs_vnode.h

+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

 */

fs/xfs/xfs_inode.c

+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;