Commit bc3048e3 authored by Peter Leckie's avatar Peter Leckie Committed by Lachlan McIlroy

[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: default avatarPeter Leckie <pleckie@sgi.com>
Signed-off-by: default avatarChristoph Hellwig <hch@infradead.org>
Signed-off-by: default avatarDavid Chinner <david@fromorbit.com>
Signed-off-by: default avatarDonald Douwsma <donaldd@sgi.com>
Signed-off-by: default avatarLachlan McIlroy <lachlan@sgi.com>
parent d112f298
...@@ -101,7 +101,7 @@ xfs_qm_dqinit( ...@@ -101,7 +101,7 @@ xfs_qm_dqinit(
if (brandnewdquot) { if (brandnewdquot) {
dqp->dq_flnext = dqp->dq_flprev = dqp; dqp->dq_flnext = dqp->dq_flprev = dqp;
mutex_init(&dqp->q_qlock); mutex_init(&dqp->q_qlock);
sv_init(&dqp->q_pinwait, SV_DEFAULT, "pdq"); init_waitqueue_head(&dqp->q_pinwait);
/* /*
* Because we want to use a counting completion, complete * Because we want to use a counting completion, complete
...@@ -131,7 +131,7 @@ xfs_qm_dqinit( ...@@ -131,7 +131,7 @@ xfs_qm_dqinit(
dqp->q_res_bcount = 0; dqp->q_res_bcount = 0;
dqp->q_res_icount = 0; dqp->q_res_icount = 0;
dqp->q_res_rtbcount = 0; dqp->q_res_rtbcount = 0;
dqp->q_pincount = 0; atomic_set(&dqp->q_pincount, 0);
dqp->q_hash = NULL; dqp->q_hash = NULL;
ASSERT(dqp->dq_flnext == dqp->dq_flprev); ASSERT(dqp->dq_flnext == dqp->dq_flprev);
...@@ -1489,7 +1489,7 @@ xfs_qm_dqpurge( ...@@ -1489,7 +1489,7 @@ xfs_qm_dqpurge(
"xfs_qm_dqpurge: dquot %p flush failed", dqp); "xfs_qm_dqpurge: dquot %p flush failed", dqp);
xfs_dqflock(dqp); xfs_dqflock(dqp);
} }
ASSERT(dqp->q_pincount == 0); ASSERT(atomic_read(&dqp->q_pincount) == 0);
ASSERT(XFS_FORCED_SHUTDOWN(mp) || ASSERT(XFS_FORCED_SHUTDOWN(mp) ||
!(dqp->q_logitem.qli_item.li_flags & XFS_LI_IN_AIL)); !(dqp->q_logitem.qli_item.li_flags & XFS_LI_IN_AIL));
......
...@@ -83,8 +83,8 @@ typedef struct xfs_dquot { ...@@ -83,8 +83,8 @@ typedef struct xfs_dquot {
xfs_qcnt_t q_res_rtbcount;/* total realtime blks used+reserved */ xfs_qcnt_t q_res_rtbcount;/* total realtime blks used+reserved */
mutex_t q_qlock; /* quota lock */ mutex_t q_qlock; /* quota lock */
struct completion q_flush; /* flush completion queue */ struct completion q_flush; /* flush completion queue */
uint q_pincount; /* pin count for this dquot */ atomic_t q_pincount; /* dquot pin count */
sv_t q_pinwait; /* sync var for pinning */ wait_queue_head_t q_pinwait; /* dquot pinning wait queue */
#ifdef XFS_DQUOT_TRACE #ifdef XFS_DQUOT_TRACE
struct ktrace *q_trace; /* trace header structure */ struct ktrace *q_trace; /* trace header structure */
#endif #endif
......
...@@ -88,25 +88,22 @@ xfs_qm_dquot_logitem_format( ...@@ -88,25 +88,22 @@ xfs_qm_dquot_logitem_format(
/* /*
* Increment the pin count of the given dquot. * Increment the pin count of the given dquot.
* This value is protected by pinlock spinlock in the xQM structure.
*/ */
STATIC void STATIC void
xfs_qm_dquot_logitem_pin( xfs_qm_dquot_logitem_pin(
xfs_dq_logitem_t *logitem) 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)); ASSERT(XFS_DQ_IS_LOCKED(dqp));
spin_lock(&(XFS_DQ_TO_QINF(dqp)->qi_pinlock)); atomic_inc(dqp->q_pincount);
dqp->q_pincount++;
spin_unlock(&(XFS_DQ_TO_QINF(dqp)->qi_pinlock));
} }
/* /*
* Decrement the pin count of the given dquot, and wake up * Decrement the pin count of the given dquot, and wake up
* anyone in xfs_dqwait_unpin() if the count goes to 0. The * 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 */ /* ARGSUSED */
STATIC void STATIC void
...@@ -114,16 +111,11 @@ xfs_qm_dquot_logitem_unpin( ...@@ -114,16 +111,11 @@ xfs_qm_dquot_logitem_unpin(
xfs_dq_logitem_t *logitem, xfs_dq_logitem_t *logitem,
int stale) int stale)
{ {
xfs_dquot_t *dqp; xfs_dquot_t *dqp = logitem->qli_dquot;
dqp = logitem->qli_dquot; ASSERT(atomic_read(&dqp->q_pincount) > 0);
ASSERT(dqp->q_pincount > 0); if (atomic_dec_and_test(&dqp->q_pincount))
spin_lock(&(XFS_DQ_TO_QINF(dqp)->qi_pinlock)); wake_up(&dqp->q_pinwait);
dqp->q_pincount--;
if (dqp->q_pincount == 0) {
sv_broadcast(&dqp->q_pinwait);
}
spin_unlock(&(XFS_DQ_TO_QINF(dqp)->qi_pinlock));
} }
/* ARGSUSED */ /* ARGSUSED */
...@@ -193,21 +185,14 @@ xfs_qm_dqunpin_wait( ...@@ -193,21 +185,14 @@ xfs_qm_dqunpin_wait(
xfs_dquot_t *dqp) xfs_dquot_t *dqp)
{ {
ASSERT(XFS_DQ_IS_LOCKED(dqp)); ASSERT(XFS_DQ_IS_LOCKED(dqp));
if (dqp->q_pincount == 0) { if (atomic_read(&dqp->q_pincount) == 0)
return; return;
}
/* /*
* Give the log a push so we don't wait here too long. * 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); xfs_log_force(dqp->q_mount, (xfs_lsn_t)0, XFS_LOG_FORCE);
spin_lock(&(XFS_DQ_TO_QINF(dqp)->qi_pinlock)); wait_event(dqp->q_pinwait, (atomic_read(&dqp->q_pincount) == 0));
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);
} }
/* /*
...@@ -310,7 +295,7 @@ xfs_qm_dquot_logitem_trylock( ...@@ -310,7 +295,7 @@ xfs_qm_dquot_logitem_trylock(
uint retval; uint retval;
dqp = qip->qli_dquot; dqp = qip->qli_dquot;
if (dqp->q_pincount > 0) if (atomic_read(&dqp->q_pincount) > 0)
return (XFS_ITEM_PINNED); return (XFS_ITEM_PINNED);
if (! xfs_qm_dqlock_nowait(dqp)) if (! xfs_qm_dqlock_nowait(dqp))
......
...@@ -1137,7 +1137,6 @@ xfs_qm_init_quotainfo( ...@@ -1137,7 +1137,6 @@ xfs_qm_init_quotainfo(
return error; return error;
} }
spin_lock_init(&qinf->qi_pinlock);
xfs_qm_list_init(&qinf->qi_dqlist, "mpdqlist", 0); xfs_qm_list_init(&qinf->qi_dqlist, "mpdqlist", 0);
qinf->qi_dqreclaims = 0; qinf->qi_dqreclaims = 0;
...@@ -1234,7 +1233,6 @@ xfs_qm_destroy_quotainfo( ...@@ -1234,7 +1233,6 @@ xfs_qm_destroy_quotainfo(
*/ */
xfs_qm_rele_quotafs_ref(mp); xfs_qm_rele_quotafs_ref(mp);
spinlock_destroy(&qi->qi_pinlock);
xfs_qm_list_destroy(&qi->qi_dqlist); xfs_qm_list_destroy(&qi->qi_dqlist);
if (qi->qi_uquotaip) { if (qi->qi_uquotaip) {
......
...@@ -106,7 +106,6 @@ typedef struct xfs_qm { ...@@ -106,7 +106,6 @@ typedef struct xfs_qm {
typedef struct xfs_quotainfo { typedef struct xfs_quotainfo {
xfs_inode_t *qi_uquotaip; /* user quota inode */ xfs_inode_t *qi_uquotaip; /* user quota inode */
xfs_inode_t *qi_gquotaip; /* group quota inode */ xfs_inode_t *qi_gquotaip; /* group quota inode */
spinlock_t qi_pinlock; /* dquot pinning lock */
xfs_dqlist_t qi_dqlist; /* all dquots in filesys */ xfs_dqlist_t qi_dqlist; /* all dquots in filesys */
int qi_dqreclaims; /* a change here indicates int qi_dqreclaims; /* a change here indicates
a removal in the dqlist */ a removal in the dqlist */
......
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