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[XFS] Clean up dquot pincount code.

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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>
This commit is contained in:
Peter Leckie 2008-10-30 17:05:04 +11:00 committed by Lachlan McIlroy
parent d112f29845
commit bc3048e3cd
5 changed files with 16 additions and 34 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
fs/xfs/quota/xfs_dquot.c
View File

@ -101,7 +101,7 @@ xfs_qm_dqinit(
if (brandnewdquot) {
dqp->dq_flnext = dqp->dq_flprev = dqp;
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
@ -131,7 +131,7 @@ xfs_qm_dqinit(
dqp->q_res_bcount = 0;
dqp->q_res_icount = 0;
dqp->q_res_rtbcount = 0;
dqp->q_pincount = 0;
atomic_set(&dqp->q_pincount, 0);
dqp->q_hash = NULL;
ASSERT(dqp->dq_flnext == dqp->dq_flprev);
@ -1489,7 +1489,7 @@ xfs_qm_dqpurge(
"xfs_qm_dqpurge: dquot %p flush failed", dqp);
xfs_dqflock(dqp);
}
ASSERT(dqp->q_pincount == 0);
ASSERT(atomic_read(&dqp->q_pincount) == 0);
ASSERT(XFS_FORCED_SHUTDOWN(mp) ||
!(dqp->q_logitem.qli_item.li_flags & XFS_LI_IN_AIL));

4
fs/xfs/quota/xfs_dquot.h
View File

@ -83,8 +83,8 @@ typedef struct xfs_dquot {
xfs_qcnt_t q_res_rtbcount;/* total realtime blks used+reserved */
mutex_t q_qlock; /* quota lock */
struct completion q_flush; /* flush completion queue */
uint q_pincount; /* pin count for this dquot */
sv_t q_pinwait; /* sync var for pinning */
atomic_t q_pincount; /* dquot pin count */
wait_queue_head_t q_pinwait; /* dquot pinning wait queue */
#ifdef XFS_DQUOT_TRACE
struct ktrace *q_trace; /* trace header structure */
#endif

37
fs/xfs/quota/xfs_dquot_item.c
View File

@ -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))

2
fs/xfs/quota/xfs_qm.c
View File

@ -1137,7 +1137,6 @@ xfs_qm_init_quotainfo(
return error;
}
spin_lock_init(&qinf->qi_pinlock);
xfs_qm_list_init(&qinf->qi_dqlist, "mpdqlist", 0);
qinf->qi_dqreclaims = 0;
@ -1234,7 +1233,6 @@ xfs_qm_destroy_quotainfo(
*/
xfs_qm_rele_quotafs_ref(mp);
spinlock_destroy(&qi->qi_pinlock);
xfs_qm_list_destroy(&qi->qi_dqlist);
if (qi->qi_uquotaip) {

1
fs/xfs/quota/xfs_qm.h
View File

@ -106,7 +106,6 @@ typedef struct xfs_qm {
typedef struct xfs_quotainfo {
xfs_inode_t *qi_uquotaip; /* user 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 */
int qi_dqreclaims; /* a change here indicates
a removal in the dqlist */