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xfs: per-filesystem dquot LRU lists
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Replace the global dquot lru lists with a per-filesystem one.

Note that the shrinker isn't wire up to the per-superblock VFS shrinker
infrastructure as would have problems summing up and splitting the counts
for inodes and dquots.  I don't think this is a major problem as the quota
cache isn't as interwinded with the inode cache as the dentry cache is,
because an inode that is dropped from the cache will generally release
a dquot reference, but most of the time it won't be the last one.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
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Christoph Hellwig authored and Ben Myers committed Mar 14, 2012
1 parent 48776fd commit f8739c3
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Showing 4 changed files with 74 additions and 78 deletions.
84 changes: 44 additions & 40 deletions fs/xfs/xfs_dquot.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -47,7 +47,7 @@
* qi->qi_dqlist_lock
* dquot->q_qlock (xfs_dqlock() and friends)
* dquot->q_flush (xfs_dqflock() and friends)
* xfs_Gqm->qm_dqfrlist_lock
* qi->qi_lru_lock
*
* If two dquots need to be locked the order is user before group/project,
* otherwise by the lowest id first, see xfs_dqlock2.
Expand All @@ -69,7 +69,7 @@ void
xfs_qm_dqdestroy(
xfs_dquot_t *dqp)
{
ASSERT(list_empty(&dqp->q_freelist));
ASSERT(list_empty(&dqp->q_lru));

mutex_destroy(&dqp->q_qlock);
kmem_zone_free(xfs_Gqm->qm_dqzone, dqp);
Expand Down Expand Up @@ -497,7 +497,7 @@ xfs_qm_dqread(
dqp->dq_flags = type;
dqp->q_core.d_id = cpu_to_be32(id);
dqp->q_mount = mp;
INIT_LIST_HEAD(&dqp->q_freelist);
INIT_LIST_HEAD(&dqp->q_lru);
mutex_init(&dqp->q_qlock);
init_waitqueue_head(&dqp->q_pinwait);

Expand Down Expand Up @@ -844,38 +844,22 @@ xfs_qm_dqget(
}


/*
* Release a reference to the dquot (decrement ref-count)
* and unlock it. If there is a group quota attached to this
* dquot, carefully release that too without tripping over
* deadlocks'n'stuff.
*/
void
xfs_qm_dqput(
STATIC void
xfs_qm_dqput_final(
struct xfs_dquot *dqp)
{
struct xfs_quotainfo *qi = dqp->q_mount->m_quotainfo;
struct xfs_dquot *gdqp;

ASSERT(dqp->q_nrefs > 0);
ASSERT(XFS_DQ_IS_LOCKED(dqp));

trace_xfs_dqput(dqp);

recurse:
if (--dqp->q_nrefs > 0) {
xfs_dqunlock(dqp);
return;
}

trace_xfs_dqput_free(dqp);

mutex_lock(&xfs_Gqm->qm_dqfrlist_lock);
if (list_empty(&dqp->q_freelist)) {
list_add_tail(&dqp->q_freelist, &xfs_Gqm->qm_dqfrlist);
xfs_Gqm->qm_dqfrlist_cnt++;
mutex_lock(&qi->qi_lru_lock);
if (list_empty(&dqp->q_lru)) {
list_add_tail(&dqp->q_lru, &qi->qi_lru_list);
qi->qi_lru_count++;
XFS_STATS_INC(xs_qm_dquot_unused);
}
mutex_unlock(&xfs_Gqm->qm_dqfrlist_lock);
mutex_unlock(&qi->qi_lru_lock);

/*
* If we just added a udquot to the freelist, then we want to release
Expand All @@ -892,10 +876,29 @@ xfs_qm_dqput(
/*
* If we had a group quota hint, release it now.
*/
if (gdqp) {
dqp = gdqp;
goto recurse;
}
if (gdqp)
xfs_qm_dqput(gdqp);
}

/*
* Release a reference to the dquot (decrement ref-count) and unlock it.
*
* If there is a group quota attached to this dquot, carefully release that
* too without tripping over deadlocks'n'stuff.
*/
void
xfs_qm_dqput(
struct xfs_dquot *dqp)
{
ASSERT(dqp->q_nrefs > 0);
ASSERT(XFS_DQ_IS_LOCKED(dqp));

trace_xfs_dqput(dqp);

if (--dqp->q_nrefs > 0)
xfs_dqunlock(dqp);
else
xfs_qm_dqput_final(dqp);
}

/*
Expand Down Expand Up @@ -1115,6 +1118,7 @@ xfs_qm_dqpurge(
{
struct xfs_mount *mp = dqp->q_mount;
struct xfs_dqhash *qh = dqp->q_hash;
struct xfs_quotainfo *qi = mp->m_quotainfo;

xfs_dqlock(dqp);

Expand Down Expand Up @@ -1165,22 +1169,22 @@ xfs_qm_dqpurge(
qh->qh_version++;
mutex_unlock(&qh->qh_lock);

mutex_lock(&mp->m_quotainfo->qi_dqlist_lock);
mutex_lock(&qi->qi_dqlist_lock);
list_del_init(&dqp->q_mplist);
mp->m_quotainfo->qi_dqreclaims++;
mp->m_quotainfo->qi_dquots--;
mutex_unlock(&mp->m_quotainfo->qi_dqlist_lock);
qi->qi_dqreclaims++;
qi->qi_dquots--;
mutex_unlock(&qi->qi_dqlist_lock);

/*
* We move dquots to the freelist as soon as their reference count
* hits zero, so it really should be on the freelist here.
*/
mutex_lock(&xfs_Gqm->qm_dqfrlist_lock);
ASSERT(!list_empty(&dqp->q_freelist));
list_del_init(&dqp->q_freelist);
xfs_Gqm->qm_dqfrlist_cnt--;
mutex_lock(&qi->qi_lru_lock);
ASSERT(!list_empty(&dqp->q_lru));
list_del_init(&dqp->q_lru);
qi->qi_lru_count--;
XFS_STATS_DEC(xs_qm_dquot_unused);
mutex_unlock(&xfs_Gqm->qm_dqfrlist_lock);
mutex_unlock(&qi->qi_lru_lock);

xfs_qm_dqdestroy(dqp);
}
Expand Down
2 changes: 1 addition & 1 deletion fs/xfs/xfs_dquot.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -47,7 +47,7 @@ struct xfs_trans;
*/
typedef struct xfs_dquot {
uint dq_flags; /* various flags (XFS_DQ_*) */
struct list_head q_freelist; /* global free list of dquots */
struct list_head q_lru; /* global free list of dquots */
struct list_head q_mplist; /* mount's list of dquots */
struct list_head q_hashlist; /* gloabl hash list of dquots */
xfs_dqhash_t *q_hash; /* the hashchain header */
Expand Down
59 changes: 25 additions & 34 deletions fs/xfs/xfs_qm.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -61,11 +61,6 @@ STATIC int xfs_qm_init_quotainos(xfs_mount_t *);
STATIC int xfs_qm_init_quotainfo(xfs_mount_t *);
STATIC int xfs_qm_shake(struct shrinker *, struct shrink_control *);

static struct shrinker xfs_qm_shaker = {
.shrink = xfs_qm_shake,
.seeks = DEFAULT_SEEKS,
};

/*
* Initialize the XQM structure.
* Note that there is not one quota manager per file system.
Expand Down Expand Up @@ -105,13 +100,6 @@ xfs_Gqm_init(void)
xfs_qm_list_init(&(xqm->qm_grp_dqhtable[i]), "gxdqh", i);
}

/*
* Freelist of all dquots of all file systems
*/
INIT_LIST_HEAD(&xqm->qm_dqfrlist);
xqm->qm_dqfrlist_cnt = 0;
mutex_init(&xqm->qm_dqfrlist_lock);

/*
* dquot zone. we register our own low-memory callback.
*/
Expand All @@ -122,8 +110,6 @@ xfs_Gqm_init(void)
} else
xqm->qm_dqzone = qm_dqzone;

register_shrinker(&xfs_qm_shaker);

/*
* The t_dqinfo portion of transactions.
*/
Expand Down Expand Up @@ -155,12 +141,6 @@ xfs_qm_destroy(
ASSERT(xqm != NULL);
ASSERT(xqm->qm_nrefs == 0);

unregister_shrinker(&xfs_qm_shaker);

mutex_lock(&xqm->qm_dqfrlist_lock);
ASSERT(list_empty(&xqm->qm_dqfrlist));
mutex_unlock(&xqm->qm_dqfrlist_lock);

hsize = xqm->qm_dqhashmask + 1;
for (i = 0; i < hsize; i++) {
xfs_qm_list_destroy(&(xqm->qm_usr_dqhtable[i]));
Expand Down Expand Up @@ -826,6 +806,10 @@ xfs_qm_init_quotainfo(
mutex_init(&qinf->qi_dqlist_lock);
lockdep_set_class(&qinf->qi_dqlist_lock, &xfs_quota_mplist_class);

INIT_LIST_HEAD(&qinf->qi_lru_list);
qinf->qi_lru_count = 0;
mutex_init(&qinf->qi_lru_lock);

qinf->qi_dqreclaims = 0;

/* mutex used to serialize quotaoffs */
Expand Down Expand Up @@ -893,6 +877,9 @@ xfs_qm_init_quotainfo(
qinf->qi_rtbwarnlimit = XFS_QM_RTBWARNLIMIT;
}

qinf->qi_shrinker.shrink = xfs_qm_shake;
qinf->qi_shrinker.seeks = DEFAULT_SEEKS;
register_shrinker(&qinf->qi_shrinker);
return 0;
}

Expand All @@ -912,6 +899,8 @@ xfs_qm_destroy_quotainfo(
ASSERT(qi != NULL);
ASSERT(xfs_Gqm != NULL);

unregister_shrinker(&qi->qi_shrinker);

/*
* Release the reference that XQM kept, so that we know
* when the XQM structure should be freed. We cannot assume
Expand Down Expand Up @@ -1623,6 +1612,7 @@ xfs_qm_dqreclaim_one(
struct list_head *dispose_list)
{
struct xfs_mount *mp = dqp->q_mount;
struct xfs_quotainfo *qi = mp->m_quotainfo;
int error;

if (!xfs_dqlock_nowait(dqp))
Expand All @@ -1638,8 +1628,8 @@ xfs_qm_dqreclaim_one(
trace_xfs_dqreclaim_want(dqp);
XFS_STATS_INC(xs_qm_dqwants);

list_del_init(&dqp->q_freelist);
xfs_Gqm->qm_dqfrlist_cnt--;
list_del_init(&dqp->q_lru);
qi->qi_lru_count--;
XFS_STATS_DEC(xs_qm_dquot_unused);
return;
}
Expand Down Expand Up @@ -1688,8 +1678,8 @@ xfs_qm_dqreclaim_one(
xfs_dqunlock(dqp);

ASSERT(dqp->q_nrefs == 0);
list_move_tail(&dqp->q_freelist, dispose_list);
xfs_Gqm->qm_dqfrlist_cnt--;
list_move_tail(&dqp->q_lru, dispose_list);
qi->qi_lru_count--;
XFS_STATS_DEC(xs_qm_dquot_unused);

trace_xfs_dqreclaim_done(dqp);
Expand All @@ -1702,7 +1692,7 @@ xfs_qm_dqreclaim_one(
/*
* Move the dquot to the tail of the list so that we don't spin on it.
*/
list_move_tail(&dqp->q_freelist, &xfs_Gqm->qm_dqfrlist);
list_move_tail(&dqp->q_lru, &qi->qi_lru_list);

trace_xfs_dqreclaim_busy(dqp);
XFS_STATS_INC(xs_qm_dqreclaim_misses);
Expand All @@ -1713,6 +1703,8 @@ xfs_qm_shake(
struct shrinker *shrink,
struct shrink_control *sc)
{
struct xfs_quotainfo *qi =
container_of(shrink, struct xfs_quotainfo, qi_shrinker);
int nr_to_scan = sc->nr_to_scan;
LIST_HEAD (dispose_list);
struct xfs_dquot *dqp;
Expand All @@ -1722,24 +1714,23 @@ xfs_qm_shake(
if (!nr_to_scan)
goto out;

mutex_lock(&xfs_Gqm->qm_dqfrlist_lock);
while (!list_empty(&xfs_Gqm->qm_dqfrlist)) {
mutex_lock(&qi->qi_lru_lock);
while (!list_empty(&qi->qi_lru_list)) {
if (nr_to_scan-- <= 0)
break;
dqp = list_first_entry(&xfs_Gqm->qm_dqfrlist, struct xfs_dquot,
q_freelist);
dqp = list_first_entry(&qi->qi_lru_list, struct xfs_dquot,
q_lru);
xfs_qm_dqreclaim_one(dqp, &dispose_list);
}
mutex_unlock(&xfs_Gqm->qm_dqfrlist_lock);
mutex_unlock(&qi->qi_lru_lock);

while (!list_empty(&dispose_list)) {
dqp = list_first_entry(&dispose_list, struct xfs_dquot,
q_freelist);
list_del_init(&dqp->q_freelist);
dqp = list_first_entry(&dispose_list, struct xfs_dquot, q_lru);
list_del_init(&dqp->q_lru);
xfs_qm_dqfree_one(dqp);
}
out:
return (xfs_Gqm->qm_dqfrlist_cnt / 100) * sysctl_vfs_cache_pressure;
return (qi->qi_lru_count / 100) * sysctl_vfs_cache_pressure;
}

/*
Expand Down
7 changes: 4 additions & 3 deletions fs/xfs/xfs_qm.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -56,9 +56,6 @@ typedef struct xfs_qm {
xfs_dqlist_t *qm_usr_dqhtable;/* udquot hash table */
xfs_dqlist_t *qm_grp_dqhtable;/* gdquot hash table */
uint qm_dqhashmask; /* # buckets in dq hashtab - 1 */
struct list_head qm_dqfrlist; /* freelist of dquots */
struct mutex qm_dqfrlist_lock;
int qm_dqfrlist_cnt;
uint qm_nrefs; /* file systems with quota on */
kmem_zone_t *qm_dqzone; /* dquot mem-alloc zone */
kmem_zone_t *qm_dqtrxzone; /* t_dqinfo of transactions */
Expand All @@ -71,6 +68,9 @@ typedef struct xfs_qm {
typedef struct xfs_quotainfo {
xfs_inode_t *qi_uquotaip; /* user quota inode */
xfs_inode_t *qi_gquotaip; /* group quota inode */
struct list_head qi_lru_list;
struct mutex qi_lru_lock;
int qi_lru_count;
struct list_head qi_dqlist; /* all dquots in filesys */
struct mutex qi_dqlist_lock;
int qi_dquots;
Expand All @@ -91,6 +91,7 @@ typedef struct xfs_quotainfo {
xfs_qcnt_t qi_isoftlimit; /* default inode count soft limit */
xfs_qcnt_t qi_rtbhardlimit;/* default realtime blk hard limit */
xfs_qcnt_t qi_rtbsoftlimit;/* default realtime blk soft limit */
struct shrinker qi_shrinker;
} xfs_quotainfo_t;


Expand Down

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