Stop reusing dquots from the freelist when allocating new ones directly, and
implement a shrinker that actually follows the specifications for the
interface. The shrinker implementation is still highly suboptimal at this
point, but we can gradually work on it.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
fs/xfs/kmem.h | 6 -
fs/xfs/xfs_dquot.c | 103 ++++---------------
fs/xfs/xfs_qm.c | 271 ++++++++++++++++----------------------------------
fs/xfs/xfs_qm.h | 9 -
fs/xfs/xfs_qm_stats.c | 4
fs/xfs/xfs_trace.h | 2
6 files changed, 120 insertions(+), 275 deletions(-)
Index: xfs/fs/xfs/kmem.h
===================================================================
--- xfs.orig/fs/xfs/kmem.h 2011-10-27 22:39:33.216674214 +0200
+++ xfs/fs/xfs/kmem.h 2011-10-27 22:40:08.594173542 +0200
@@ -115,10 +115,4 @@ kmem_zone_destroy(kmem_zone_t *zone)
extern void *kmem_zone_alloc(kmem_zone_t *, unsigned int __nocast);
extern void *kmem_zone_zalloc(kmem_zone_t *, unsigned int __nocast);
-static inline int
-kmem_shake_allow(gfp_t gfp_mask)
-{
- return ((gfp_mask & __GFP_WAIT) && (gfp_mask & __GFP_FS));
-}
-
#endif /* __XFS_SUPPORT_KMEM_H__ */
Index: xfs/fs/xfs/xfs_qm.c
===================================================================
--- xfs.orig/fs/xfs/xfs_qm.c 2011-10-27 22:40:08.124671538 +0200
+++ xfs/fs/xfs/xfs_qm.c 2011-10-27 22:40:08.594173542 +0200
@@ -50,7 +50,6 @@
*/
struct mutex xfs_Gqm_lock;
struct xfs_qm *xfs_Gqm;
-uint ndquot;
kmem_zone_t *qm_dqzone;
kmem_zone_t *qm_dqtrxzone;
@@ -93,7 +92,6 @@ xfs_Gqm_init(void)
goto out_free_udqhash;
hsize /= sizeof(xfs_dqhash_t);
- ndquot = hsize << 8;
xqm = kmem_zalloc(sizeof(xfs_qm_t), KM_SLEEP);
xqm->qm_dqhashmask = hsize - 1;
@@ -137,7 +135,6 @@ xfs_Gqm_init(void)
xqm->qm_dqtrxzone = qm_dqtrxzone;
atomic_set(&xqm->qm_totaldquots, 0);
- xqm->qm_dqfree_ratio = XFS_QM_DQFREE_RATIO;
xqm->qm_nrefs = 0;
return xqm;
@@ -1600,214 +1597,130 @@ xfs_qm_init_quotainos(
return 0;
}
+STATIC bool
+xfs_qm_dqreclaim_one(
+ struct xfs_dquot *dqp)
+{
+ struct xfs_mount *mp = dqp->q_mount;
+ int error;
+ /*
+ * Move the dquot to the tail so that we don't spin on it.
+ */
+ if (!xfs_dqlock_nowait(dqp))
+ goto out_busy;
-/*
- * Pop the least recently used dquot off the freelist and recycle it.
- */
-STATIC struct xfs_dquot *
-xfs_qm_dqreclaim_one(void)
-{
- struct xfs_dquot *dqp;
- int restarts = 0;
+ /*
+ * This dquot has already been grabbed by dqlookup.
+ * Remove it from the freelist and try again.
+ */
+ if (dqp->q_nrefs) {
+ xfs_dqunlock(dqp);
- mutex_lock(&xfs_Gqm->qm_dqfrlist_lock);
-restart:
- list_for_each_entry(dqp, &xfs_Gqm->qm_dqfrlist, q_freelist) {
- struct xfs_mount *mp = dqp->q_mount;
+ trace_xfs_dqreclaim_want(dqp);
+ XQM_STATS_INC(xqmstats.xs_qm_dqwants);
- if (!xfs_dqlock_nowait(dqp))
- continue;
+ list_del_init(&dqp->q_freelist);
+ xfs_Gqm->qm_dqfrlist_cnt--;
+ return true;
+ }
- /*
- * This dquot has already been grabbed by dqlookup.
- * Remove it from the freelist and try again.
- */
- if (dqp->q_nrefs) {
- trace_xfs_dqreclaim_want(dqp);
- XQM_STATS_INC(xqmstats.xs_qm_dqwants);
-
- list_del_init(&dqp->q_freelist);
- xfs_Gqm->qm_dqfrlist_cnt--;
- restarts++;
- goto dqunlock;
- }
+ ASSERT(dqp->q_hash);
+ ASSERT(!list_empty(&dqp->q_mplist));
- ASSERT(dqp->q_hash);
- ASSERT(!list_empty(&dqp->q_mplist));
+ /*
+ * Try to grab the flush lock. If this dquot is in the process of
+ * getting flushed to disk, we don't want to reclaim it.
+ */
+ if (!xfs_dqflock_nowait(dqp))
+ goto out_busy;
- /*
- * Try to grab the flush lock. If this dquot is in the process
- * of getting flushed to disk, we don't want to reclaim it.
- */
- if (!xfs_dqflock_nowait(dqp))
- goto dqunlock;
+ /*
+ * We have the flush lock so we know that this is not in the
+ * process of being flushed. So, if this is dirty, flush it
+ * DELWRI so that we don't get a freelist infested with
+ * dirty dquots.
+ */
+ if (XFS_DQ_IS_DIRTY(dqp)) {
+ trace_xfs_dqreclaim_dirty(dqp);
/*
- * We have the flush lock so we know that this is not in the
- * process of being flushed. So, if this is dirty, flush it
- * DELWRI so that we don't get a freelist infested with
- * dirty dquots.
+ * We flush it delayed write, so don't bother releasing the
+ * freelist lock.
*/
- if (XFS_DQ_IS_DIRTY(dqp)) {
- int error;
-
- trace_xfs_dqreclaim_dirty(dqp);
-
- /*
- * We flush it delayed write, so don't bother
- * releasing the freelist lock.
- */
- error = xfs_qm_dqflush(dqp, 0);
- if (error) {
- xfs_warn(mp, "%s: dquot %p flush failed",
- __func__, dqp);
- }
- goto dqunlock;
+ error = xfs_qm_dqflush(dqp, 0);
+ if (error) {
+ xfs_warn(mp, "%s: dquot %p flush failed",
+ __func__, dqp);
}
- xfs_dqfunlock(dqp);
/*
- * Prevent lookups now that we are past the point of no return.
+ * Give the dquot another try on the freelist, as the
+ * flushing will take some time.
*/
- dqp->dq_flags |= XFS_DQ_FREEING;
- xfs_dqunlock(dqp);
-
- mutex_lock(&dqp->q_hash->qh_lock);
- list_del_init(&dqp->q_hashlist);
- dqp->q_hash->qh_version++;
- mutex_unlock(&dqp->q_hash->qh_lock);
-
- mutex_lock(&mp->m_quotainfo->qi_dqlist_lock);
- list_del_init(&dqp->q_mplist);
- mp->m_quotainfo->qi_dquots--;
- mp->m_quotainfo->qi_dqreclaims++;
- mutex_unlock(&mp->m_quotainfo->qi_dqlist_lock);
-
- ASSERT(dqp->q_nrefs == 0);
- list_del_init(&dqp->q_freelist);
- xfs_Gqm->qm_dqfrlist_cnt--;
-
- mutex_unlock(&xfs_Gqm->qm_dqfrlist_lock);
- return dqp;
-dqunlock:
- xfs_dqunlock(dqp);
- if (restarts >= XFS_QM_RECLAIM_MAX_RESTARTS)
- break;
- goto restart;
+ goto out_busy;
}
+ xfs_dqfunlock(dqp);
- mutex_unlock(&xfs_Gqm->qm_dqfrlist_lock);
- return NULL;
-}
+ /*
+ * Prevent lookups now that we are past the point of no return.
+ */
+ dqp->dq_flags |= XFS_DQ_FREEING;
+ xfs_dqunlock(dqp);
-/*
- * Traverse the freelist of dquots and attempt to reclaim a maximum of
- * 'howmany' dquots. This operation races with dqlookup(), and attempts to
- * favor the lookup function ...
- */
-STATIC int
-xfs_qm_shake_freelist(
- int howmany)
-{
- int nreclaimed = 0;
- xfs_dquot_t *dqp;
+ mutex_lock(&dqp->q_hash->qh_lock);
+ list_del_init(&dqp->q_hashlist);
+ dqp->q_hash->qh_version++;
+ mutex_unlock(&dqp->q_hash->qh_lock);
+
+ mutex_lock(&mp->m_quotainfo->qi_dqlist_lock);
+ list_del_init(&dqp->q_mplist);
+ mp->m_quotainfo->qi_dquots--;
+ mp->m_quotainfo->qi_dqreclaims++;
+ mutex_unlock(&mp->m_quotainfo->qi_dqlist_lock);
+
+ ASSERT(dqp->q_nrefs == 0);
+ list_del_init(&dqp->q_freelist);
+ xfs_Gqm->qm_dqfrlist_cnt--;
+ XQM_STATS_INC(xqmstats.xs_qm_dqreclaims);
- if (howmany <= 0)
- return 0;
+ xfs_qm_dqdestroy(dqp);
+ return true;
- while (nreclaimed < howmany) {
- dqp = xfs_qm_dqreclaim_one();
- if (!dqp)
- return nreclaimed;
- xfs_qm_dqdestroy(dqp);
- nreclaimed++;
- }
- return nreclaimed;
+out_busy:
+ xfs_dqunlock(dqp);
+ return false;
}
-/*
- * The kmem_shake interface is invoked when memory is running low.
- */
-/* ARGSUSED */
STATIC int
xfs_qm_shake(
- struct shrinker *shrink,
- struct shrink_control *sc)
+ struct shrinker *shrink,
+ struct shrink_control *sc)
{
- int ndqused, nfree, n;
- gfp_t gfp_mask = sc->gfp_mask;
-
- if (!kmem_shake_allow(gfp_mask))
- return 0;
- if (!xfs_Gqm)
- return 0;
-
- nfree = xfs_Gqm->qm_dqfrlist_cnt; /* free dquots */
- /* incore dquots in all f/s's */
- ndqused = atomic_read(&xfs_Gqm->qm_totaldquots) - nfree;
-
- ASSERT(ndqused >= 0);
+ int nr_to_scan = sc->nr_to_scan;
+ struct xfs_dquot *dqp;
- if (nfree <= ndqused && nfree < ndquot)
+ if ((sc->gfp_mask & (__GFP_FS|__GFP_WAIT)) != (__GFP_FS|__GFP_WAIT))
return 0;
- ndqused *= xfs_Gqm->qm_dqfree_ratio; /* target # of free dquots */
- n = nfree - ndqused - ndquot; /* # over target */
-
- return xfs_qm_shake_freelist(MAX(nfree, n));
-}
-
-
-/*------------------------------------------------------------------*/
+ if (!nr_to_scan)
+ goto out;
-/*
- * Return a new incore dquot. Depending on the number of
- * dquots in the system, we either allocate a new one on the kernel heap,
- * or reclaim a free one.
- * Return value is B_TRUE if we allocated a new dquot, B_FALSE if we managed
- * to reclaim an existing one from the freelist.
- */
-boolean_t
-xfs_qm_dqalloc_incore(
- xfs_dquot_t **O_dqpp)
-{
- xfs_dquot_t *dqp;
+ mutex_lock(&xfs_Gqm->qm_dqfrlist_lock);
+ while (!list_empty(&xfs_Gqm->qm_dqfrlist)) {
+ if (nr_to_scan-- <= 0)
+ break;
+ dqp = list_first_entry(&xfs_Gqm->qm_dqfrlist, struct xfs_dquot,
+ q_freelist);
- /*
- * Check against high water mark to see if we want to pop
- * a nincompoop dquot off the freelist.
- */
- if (atomic_read(&xfs_Gqm->qm_totaldquots) >= ndquot) {
- /*
- * Try to recycle a dquot from the freelist.
- */
- if ((dqp = xfs_qm_dqreclaim_one())) {
- XQM_STATS_INC(xqmstats.xs_qm_dqreclaims);
- /*
- * Just zero the core here. The rest will get
- * reinitialized by caller. XXX we shouldn't even
- * do this zero ...
- */
- memset(&dqp->q_core, 0, sizeof(dqp->q_core));
- *O_dqpp = dqp;
- return B_FALSE;
- }
- XQM_STATS_INC(xqmstats.xs_qm_dqreclaim_misses);
+ if (!xfs_qm_dqreclaim_one(dqp))
+ list_move_tail(&dqp->q_freelist, &xfs_Gqm->qm_dqfrlist);
}
-
- /*
- * Allocate a brand new dquot on the kernel heap and return it
- * to the caller to initialize.
- */
- ASSERT(xfs_Gqm->qm_dqzone != NULL);
- *O_dqpp = kmem_zone_zalloc(xfs_Gqm->qm_dqzone, KM_SLEEP);
- atomic_inc(&xfs_Gqm->qm_totaldquots);
-
- return B_TRUE;
+ mutex_unlock(&xfs_Gqm->qm_dqfrlist_lock);
+out:
+ return (xfs_Gqm->qm_dqfrlist_cnt / 100) * sysctl_vfs_cache_pressure;
}
-
/*
* Start a transaction and write the incore superblock changes to
* disk. flags parameter indicates which fields have changed.
Index: xfs/fs/xfs/xfs_dquot.c
===================================================================
--- xfs.orig/fs/xfs/xfs_dquot.c 2011-10-27 22:40:07.534173092 +0200
+++ xfs/fs/xfs/xfs_dquot.c 2011-10-27 22:40:08.598176882 +0200
@@ -64,82 +64,6 @@ int xfs_dqerror_mod = 33;
static struct lock_class_key xfs_dquot_other_class;
/*
- * Allocate and initialize a dquot. We don't always allocate fresh memory;
- * we try to reclaim a free dquot if the number of incore dquots are above
- * a threshold.
- * The only field inside the core that gets initialized at this point
- * is the d_id field. The idea is to fill in the entire q_core
- * when we read in the on disk dquot.
- */
-STATIC xfs_dquot_t *
-xfs_qm_dqinit(
- xfs_mount_t *mp,
- xfs_dqid_t id,
- uint type)
-{
- xfs_dquot_t *dqp;
- boolean_t brandnewdquot;
-
- brandnewdquot = xfs_qm_dqalloc_incore(&dqp);
- dqp->dq_flags = type;
- dqp->q_core.d_id = cpu_to_be32(id);
- dqp->q_mount = mp;
-
- /*
- * No need to re-initialize these if this is a reclaimed dquot.
- */
- if (brandnewdquot) {
- INIT_LIST_HEAD(&dqp->q_freelist);
- mutex_init(&dqp->q_qlock);
- init_waitqueue_head(&dqp->q_pinwait);
-
- /*
- * Because we want to use a counting completion, complete
- * the flush completion once to allow a single access to
- * the flush completion without blocking.
- */
- init_completion(&dqp->q_flush);
- complete(&dqp->q_flush);
-
- trace_xfs_dqinit(dqp);
- } else {
- /*
- * Only the q_core portion was zeroed in dqreclaim_one().
- * So, we need to reset others.
- */
- dqp->q_nrefs = 0;
- dqp->q_blkno = 0;
- INIT_LIST_HEAD(&dqp->q_mplist);
- INIT_LIST_HEAD(&dqp->q_hashlist);
- dqp->q_bufoffset = 0;
- dqp->q_fileoffset = 0;
- dqp->q_transp = NULL;
- dqp->q_gdquot = NULL;
- dqp->q_res_bcount = 0;
- dqp->q_res_icount = 0;
- dqp->q_res_rtbcount = 0;
- atomic_set(&dqp->q_pincount, 0);
- dqp->q_hash = NULL;
- ASSERT(list_empty(&dqp->q_freelist));
-
- trace_xfs_dqreuse(dqp);
- }
-
- /*
- * In either case we need to make sure group quotas have a different
- * lock class than user quotas, to make sure lockdep knows we can
- * locks of one of each at the same time.
- */
- if (!(type & XFS_DQ_USER))
- lockdep_set_class(&dqp->q_qlock, &xfs_dquot_other_class);
-
- /*
- * log item gets initialized later
- */
- return (dqp);
-}
-
-/*
* This is called to free all the memory associated with a dquot
*/
void
@@ -568,7 +492,32 @@ xfs_qm_dqread(
int error;
int cancelflags = 0;
- dqp = xfs_qm_dqinit(mp, id, type);
+
+ dqp = kmem_zone_zalloc(xfs_Gqm->qm_dqzone, KM_SLEEP);
+
+ dqp->dq_flags = type;
+ dqp->q_core.d_id = cpu_to_be32(id);
+ dqp->q_mount = mp;
+ INIT_LIST_HEAD(&dqp->q_freelist);
+ mutex_init(&dqp->q_qlock);
+ init_waitqueue_head(&dqp->q_pinwait);
+
+ /*
+ * Because we want to use a counting completion, complete
+ * the flush completion once to allow a single access to
+ * the flush completion without blocking.
+ */
+ init_completion(&dqp->q_flush);
+ complete(&dqp->q_flush);
+
+ /*
+ * Make sure group quotas have a different lock class than user
+ * quotas.
+ */
+ if (!(type & XFS_DQ_USER))
+ lockdep_set_class(&dqp->q_qlock, &xfs_dquot_other_class);
+
+ atomic_inc(&xfs_Gqm->qm_totaldquots);
trace_xfs_dqread(dqp);
Index: xfs/fs/xfs/xfs_qm.h
===================================================================
--- xfs.orig/fs/xfs/xfs_qm.h 2011-10-27 22:40:01.234172361 +0200
+++ xfs/fs/xfs/xfs_qm.h 2011-10-27 22:40:08.606225990 +0200
@@ -26,7 +26,6 @@
struct xfs_qm;
struct xfs_inode;
-extern uint ndquot;
extern struct mutex xfs_Gqm_lock;
extern struct xfs_qm *xfs_Gqm;
extern kmem_zone_t *qm_dqzone;
@@ -38,12 +37,6 @@ extern kmem_zone_t *qm_dqtrxzone;
#define XFS_QM_RECLAIM_MAX_RESTARTS 4
/*
- * Ideal ratio of free to in use dquots. Quota manager makes an attempt
- * to keep this balance.
- */
-#define XFS_QM_DQFREE_RATIO 2
-
-/*
* Dquot hashtable constants/threshold values.
*/
#define XFS_QM_HASHSIZE_LOW (PAGE_SIZE / sizeof(xfs_dqhash_t))
@@ -74,7 +67,6 @@ typedef struct xfs_qm {
int qm_dqfrlist_cnt;
atomic_t qm_totaldquots; /* total incore dquots */
uint qm_nrefs; /* file systems with quota on */
- int qm_dqfree_ratio;/* ratio of free to inuse dquots */
kmem_zone_t *qm_dqzone; /* dquot mem-alloc zone */
kmem_zone_t *qm_dqtrxzone; /* t_dqinfo of transactions */
} xfs_qm_t;
@@ -143,7 +135,6 @@ extern int xfs_qm_quotacheck(xfs_mount_
extern int xfs_qm_write_sb_changes(xfs_mount_t *, __int64_t);
/* dquot stuff */
-extern boolean_t xfs_qm_dqalloc_incore(xfs_dquot_t **);
extern int xfs_qm_dqpurge_all(xfs_mount_t *, uint);
extern void xfs_qm_dqrele_all_inodes(xfs_mount_t *, uint);
Index: xfs/fs/xfs/xfs_qm_stats.c
===================================================================
--- xfs.orig/fs/xfs/xfs_qm_stats.c 2011-10-27 22:39:33.264675954 +0200
+++ xfs/fs/xfs/xfs_qm_stats.c 2011-10-27 22:40:08.610173785 +0200
@@ -42,9 +42,9 @@ static int xqm_proc_show(struct seq_file
{
/* maximum; incore; ratio free to inuse; freelist */
seq_printf(m, "%d\t%d\t%d\t%u\n",
- ndquot,
+ INT_MAX,
xfs_Gqm? atomic_read(&xfs_Gqm->qm_totaldquots) : 0,
- xfs_Gqm? xfs_Gqm->qm_dqfree_ratio : 0,
+ 0,
xfs_Gqm? xfs_Gqm->qm_dqfrlist_cnt : 0);
return 0;
}
Index: xfs/fs/xfs/xfs_trace.h
===================================================================
--- xfs.orig/fs/xfs/xfs_trace.h 2011-10-27 22:40:03.870173003 +0200
+++ xfs/fs/xfs/xfs_trace.h 2011-10-27 22:40:08.610173785 +0200
@@ -736,8 +736,6 @@ DEFINE_DQUOT_EVENT(xfs_dqreclaim_dirty);
DEFINE_DQUOT_EVENT(xfs_dqreclaim_unlink);
DEFINE_DQUOT_EVENT(xfs_dqattach_found);
DEFINE_DQUOT_EVENT(xfs_dqattach_get);
-DEFINE_DQUOT_EVENT(xfs_dqinit);
-DEFINE_DQUOT_EVENT(xfs_dqreuse);
DEFINE_DQUOT_EVENT(xfs_dqalloc);
DEFINE_DQUOT_EVENT(xfs_dqtobp_read);
DEFINE_DQUOT_EVENT(xfs_dqread);
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