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xfs: replace i_pin_wait with a bit waitqueue

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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>
This commit is contained in:
Christoph Hellwig 2011-12-18 20:00:10 +00:00 committed by Ben Myers
parent 474fce0675
commit f392e6319a
4 changed files with 24 additions and 9 deletions
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27
fs/xfs/xfs_inode.c
View File

@ -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;
}

3
fs/xfs/xfs_inode.h
View File

@ -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

2
fs/xfs/xfs_inode_item.c
View File

@ -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);
}
/*

1
fs/xfs/xfs_super.c
View File

@ -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);