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authorPeter Leckie <pleckie@sgi.com>2008-10-30 17:05:04 +1100
committerLachlan McIlroy <lachlan@sgi.com>2008-10-30 17:05:04 +1100
commitbc3048e3cd3806ccfd5b16b1a30e5d6013abbd3d (patch)
treec6e27010cb66cc52f41bc696def885cb672fb61f /fs/xfs/quota/xfs_dquot_item.c
parentd112f2984592acb774187b3adddc107fb0825500 (diff)
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[XFS] Clean up dquot pincount code.
This is a code cleanup and optimization that removes a per mount point spinlock from the quota code and cleans up the code. The patch changes the pincount from being an int protected by a spinlock to an atomic_t allowing the pincount to be manipulated without holding the spinlock. This cleanup also protects against random wakup's of both the aild and xfssyncd by reevaluating the pincount after been woken. Two latter patches will address the Spurious wakeups. SGI-PV: 986789 SGI-Modid: xfs-linux-melb:xfs-kern:32215a Signed-off-by: Peter Leckie <pleckie@sgi.com> Signed-off-by: Christoph Hellwig <hch@infradead.org> Signed-off-by: David Chinner <david@fromorbit.com> Signed-off-by: Donald Douwsma <donaldd@sgi.com> Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>
Diffstat (limited to 'fs/xfs/quota/xfs_dquot_item.c')
-rw-r--r--fs/xfs/quota/xfs_dquot_item.c37
1 files changed, 11 insertions, 26 deletions
diff --git a/fs/xfs/quota/xfs_dquot_item.c b/fs/xfs/quota/xfs_dquot_item.c
index f028644..e33f864 100644
--- a/fs/xfs/quota/xfs_dquot_item.c
+++ b/fs/xfs/quota/xfs_dquot_item.c
@@ -88,25 +88,22 @@ xfs_qm_dquot_logitem_format(
/*
* Increment the pin count of the given dquot.
- * This value is protected by pinlock spinlock in the xQM structure.
*/
STATIC void
xfs_qm_dquot_logitem_pin(
xfs_dq_logitem_t *logitem)
{
- xfs_dquot_t *dqp;
+ xfs_dquot_t *dqp = logitem->qli_dquot;
- dqp = logitem->qli_dquot;
ASSERT(XFS_DQ_IS_LOCKED(dqp));
- spin_lock(&(XFS_DQ_TO_QINF(dqp)->qi_pinlock));
- dqp->q_pincount++;
- spin_unlock(&(XFS_DQ_TO_QINF(dqp)->qi_pinlock));
+ atomic_inc(dqp->q_pincount);
}
/*
* Decrement the pin count of the given dquot, and wake up
* anyone in xfs_dqwait_unpin() if the count goes to 0. The
- * dquot must have been previously pinned with a call to xfs_dqpin().
+ * dquot must have been previously pinned with a call to
+ * xfs_qm_dquot_logitem_pin().
*/
/* ARGSUSED */
STATIC void
@@ -114,16 +111,11 @@ xfs_qm_dquot_logitem_unpin(
xfs_dq_logitem_t *logitem,
int stale)
{
- xfs_dquot_t *dqp;
+ xfs_dquot_t *dqp = logitem->qli_dquot;
- dqp = logitem->qli_dquot;
- ASSERT(dqp->q_pincount > 0);
- spin_lock(&(XFS_DQ_TO_QINF(dqp)->qi_pinlock));
- dqp->q_pincount--;
- if (dqp->q_pincount == 0) {
- sv_broadcast(&dqp->q_pinwait);
- }
- spin_unlock(&(XFS_DQ_TO_QINF(dqp)->qi_pinlock));
+ ASSERT(atomic_read(&dqp->q_pincount) > 0);
+ if (atomic_dec_and_test(&dqp->q_pincount))
+ wake_up(&dqp->q_pinwait);
}
/* ARGSUSED */
@@ -193,21 +185,14 @@ xfs_qm_dqunpin_wait(
xfs_dquot_t *dqp)
{
ASSERT(XFS_DQ_IS_LOCKED(dqp));
- if (dqp->q_pincount == 0) {
+ if (atomic_read(&dqp->q_pincount) == 0)
return;
- }
/*
* Give the log a push so we don't wait here too long.
*/
xfs_log_force(dqp->q_mount, (xfs_lsn_t)0, XFS_LOG_FORCE);
- spin_lock(&(XFS_DQ_TO_QINF(dqp)->qi_pinlock));
- if (dqp->q_pincount == 0) {
- spin_unlock(&(XFS_DQ_TO_QINF(dqp)->qi_pinlock));
- return;
- }
- sv_wait(&(dqp->q_pinwait), PINOD,
- &(XFS_DQ_TO_QINF(dqp)->qi_pinlock), s);
+ wait_event(dqp->q_pinwait, (atomic_read(&dqp->q_pincount) == 0));
}
/*
@@ -310,7 +295,7 @@ xfs_qm_dquot_logitem_trylock(
uint retval;
dqp = qip->qli_dquot;
- if (dqp->q_pincount > 0)
+ if (atomic_read(&dqp->q_pincount) > 0)
return (XFS_ITEM_PINNED);
if (! xfs_qm_dqlock_nowait(dqp))