From bc3048e3cd3806ccfd5b16b1a30e5d6013abbd3d Mon Sep 17 00:00:00 2001 From: Peter Leckie Date: Thu, 30 Oct 2008 17:05:04 +1100 Subject: [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 Signed-off-by: Christoph Hellwig Signed-off-by: David Chinner Signed-off-by: Donald Douwsma Signed-off-by: Lachlan McIlroy diff --git a/fs/xfs/quota/xfs_dquot.c b/fs/xfs/quota/xfs_dquot.c index f2705f2..d3f4fbb 100644 --- a/fs/xfs/quota/xfs_dquot.c +++ b/fs/xfs/quota/xfs_dquot.c @@ -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)); diff --git a/fs/xfs/quota/xfs_dquot.h b/fs/xfs/quota/xfs_dquot.h index 8958d0f..7e45533 100644 --- a/fs/xfs/quota/xfs_dquot.h +++ b/fs/xfs/quota/xfs_dquot.h @@ -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 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)) diff --git a/fs/xfs/quota/xfs_qm.c b/fs/xfs/quota/xfs_qm.c index df0ffef..270f775 100644 --- a/fs/xfs/quota/xfs_qm.c +++ b/fs/xfs/quota/xfs_qm.c @@ -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) { diff --git a/fs/xfs/quota/xfs_qm.h b/fs/xfs/quota/xfs_qm.h index 44f2534..4f2de977 100644 --- a/fs/xfs/quota/xfs_qm.h +++ b/fs/xfs/quota/xfs_qm.h @@ -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 */ -- cgit v0.10.2