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Commit f392e631 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Ben Myers
Browse files

xfs: replace i_pin_wait with a bit waitqueue 



Replace i_pin_wait, which is only used during synchronous inode flushing
with a bit waitqueue.  This trades off a much smaller inode against
slightly slower wakeup performance, and saves 12 (32-bit) or 20 (64-bit)
bytes in the XFS inode.

Reviewed-by: default avatarAlex Elder <aelder@sgi.com>
Reviewed-by: default avatarDave Chinner <dchinner@redhat.com>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarBen Myers <bpm@sgi.com>
parent 474fce06

fs/xfs/xfs_inode.c

+21 −6
Original line number Diff line number Diff line
@@ -2037,7 +2037,7 @@ xfs_idestroy_fork( 
 * once someone is waiting for it to be unpinned.

 */

static void

xfs_iunpin_nowait(

xfs_iunpin(

	struct xfs_inode	*ip)

{

	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL|XFS_ILOCK_SHARED));
@@ -2049,14 +2049,29 @@ xfs_iunpin_nowait( 


}



static void

__xfs_iunpin_wait(

	struct xfs_inode	*ip)

{

	wait_queue_head_t *wq = bit_waitqueue(&ip->i_flags, __XFS_IPINNED_BIT);

	DEFINE_WAIT_BIT(wait, &ip->i_flags, __XFS_IPINNED_BIT);



	xfs_iunpin(ip);



	do {

		prepare_to_wait(wq, &wait.wait, TASK_UNINTERRUPTIBLE);

		if (xfs_ipincount(ip))

			io_schedule();

	} while (xfs_ipincount(ip));

	finish_wait(wq, &wait.wait);

}



void

xfs_iunpin_wait(

	struct xfs_inode	*ip)

{

	if (xfs_ipincount(ip)) {

		xfs_iunpin_nowait(ip);

		wait_event(ip->i_ipin_wait, (xfs_ipincount(ip) == 0));

	}

	if (xfs_ipincount(ip))

		__xfs_iunpin_wait(ip);

}



/*
@@ -2415,7 +2430,7 @@ xfs_iflush( 
	 * out for us if they occur after the log force completes.

	 */

	if (!(flags & SYNC_WAIT) && xfs_ipincount(ip)) {

		xfs_iunpin_nowait(ip);

		xfs_iunpin(ip);

		xfs_ifunlock(ip);

		return EAGAIN;

	}

fs/xfs/xfs_inode.h

+2 −1
Original line number Diff line number Diff line
@@ -238,7 +238,6 @@ typedef struct xfs_inode { 
	mrlock_t		i_lock;		/* inode lock */

	mrlock_t		i_iolock;	/* inode IO lock */

	atomic_t		i_pincount;	/* inode pin count */

	wait_queue_head_t	i_ipin_wait;	/* inode pinning wait queue */

	spinlock_t		i_flags_lock;	/* inode i_flags lock */

	/* Miscellaneous state. */

	unsigned long		i_flags;	/* see defined flags below */
@@ -367,6 +366,8 @@ xfs_set_projid(struct xfs_inode *ip, 
#define XFS_IDIRTY_RELEASE	(1 << 6) /* dirty release already seen */

#define __XFS_IFLOCK_BIT	7	 /* inode is being flushed right now */

#define XFS_IFLOCK		(1 << __XFS_IFLOCK_BIT)

#define __XFS_IPINNED_BIT	8	 /* wakeup key for zero pin count */

#define XFS_IPINNED		(1 << __XFS_IPINNED_BIT)



/*

 * Per-lifetime flags need to be reset when re-using a reclaimable inode during

fs/xfs/xfs_inode_item.c

+1 −1
Original line number Diff line number Diff line
@@ -555,7 +555,7 @@ xfs_inode_item_unpin( 
	trace_xfs_inode_unpin(ip, _RET_IP_);

	ASSERT(atomic_read(&ip->i_pincount) > 0);

	if (atomic_dec_and_test(&ip->i_pincount))

		wake_up(&ip->i_ipin_wait);

		wake_up_bit(&ip->i_flags, __XFS_IPINNED_BIT);

}



/*

fs/xfs/xfs_super.c

+0 −1
Original line number Diff line number Diff line
@@ -828,7 +828,6 @@ xfs_fs_inode_init_once( 
	/* xfs inode */

	atomic_set(&ip->i_pincount, 0);

	spin_lock_init(&ip->i_flags_lock);

	init_waitqueue_head(&ip->i_ipin_wait);



	mrlock_init(&ip->i_lock, MRLOCK_ALLOW_EQUAL_PRI|MRLOCK_BARRIER,

		     "xfsino", ip->i_ino);