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: Alex Elder <aelder@sgi.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ben Myers <bpm@sgi.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h
index 960d2a89b3ac..4acbe740be46 100644
--- a/fs/xfs/xfs_inode.h
+++ b/fs/xfs/xfs_inode.h
@@ -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