[PATCH 5/8] xfs: per-filesystem dquot LRU lists

Christoph Hellwig
2012-02-20T02:29:05Z

[-- Attachment #1: xfs-quota-per-mount-lru-2 --]
[-- Type: text/plain, Size: 11600 bytes --]

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>

---
fs/xfs/xfs_dquot.c | 85 +++++++++++++++++++++++++++--------------------------
fs/xfs/xfs_dquot.h | 2 -
fs/xfs/xfs_qm.c | 59 +++++++++++++++---------------------
fs/xfs/xfs_qm.h | 7 ++--
4 files changed, 74 insertions(+), 79 deletions(-)

Index: xfs/fs/xfs/xfs_dquot.c
===================================================================
--- xfs.orig/fs/xfs/xfs_dquot.c 2012-02-17 19:11:41.000000000 -0800
+++ xfs/fs/xfs/xfs_dquot.c 2012-02-17 19:17:23.773327994 -0800
@@ -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.
@@ -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);
@@ -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);

@@ -844,38 +844,22 @@ restart:
}

-/*
- * 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
@@ -892,10 +876,29 @@ recurse:
/*
* 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);
}

/*
@@ -1126,6 +1129,7 @@ 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);

@@ -1176,22 +1180,21 @@ 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--;
- XFS_STATS_DEC(xs_qm_dquot_unused);
- mutex_unlock(&xfs_Gqm->qm_dqfrlist_lock);
+ mutex_lock(&qi->qi_lru_lock);
+ ASSERT(!list_empty(&dqp->q_lru));
+ list_del_init(&dqp->q_lru);
+ qi->qi_lru_count--;
+ mutex_unlock(&qi->qi_lru_lock);

xfs_qm_dqdestroy(dqp);
}
Index: xfs/fs/xfs/xfs_dquot.h
===================================================================
--- xfs.orig/fs/xfs/xfs_dquot.h 2012-02-17 18:45:50.000000000 -0800
+++ xfs/fs/xfs/xfs_dquot.h 2012-02-17 19:13:51.929995233 -0800
@@ -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 */
Index: xfs/fs/xfs/xfs_qm.c
===================================================================
--- xfs.orig/fs/xfs/xfs_qm.c 2012-02-17 19:11:57.693328883 -0800
+++ xfs/fs/xfs/xfs_qm.c 2012-02-17 19:18:07.813328143 -0800
@@ -61,11 +61,6 @@ STATIC int xfs_qm_init_quotainos(xfs_mou
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.
@@ -106,13 +101,6 @@ xfs_Gqm_init(void)
}

/*
- * 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.
*/
if (!qm_dqzone) {
@@ -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.
*/
@@ -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]));
@@ -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 */
@@ -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;
}

@@ -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
@@ -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))
@@ -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;
}
@@ -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);
@@ -1702,7 +1692,7 @@ out_busy:
/*
* 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);
@@ -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;
@@ -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;
}

/*
Index: xfs/fs/xfs/xfs_qm.h
===================================================================
--- xfs.orig/fs/xfs/xfs_qm.h 2012-02-17 19:10:49.000000000 -0800
+++ xfs/fs/xfs/xfs_qm.h 2012-02-17 19:14:06.713328536 -0800
@@ -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 */
@@ -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;
@@ -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;