1 files changed, 111 insertions, 180 deletions

diff --git a/fs/xfs/xfs_qm.c b/fs/xfs/xfs_qm.c
index 671f37eae1c7..c436def733bf 100644
--- a/fs/xfs/xfs_qm.c
+++ b/fs/xfs/xfs_qm.c
@@ -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;
 
@@ -1600,216 +1597,150 @@ xfs_qm_init_quotainos(
         return 0;
 }
 
+STATIC void
+xfs_qm_dqfree_one(
+        struct xfs_dquot        *dqp)
+{
+        struct xfs_mount        *mp = dqp->q_mount;
+        struct xfs_quotainfo    *qi = mp->m_quotainfo;
 
+        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);
 
-/*
- * Pop the least recently used dquot off the freelist and recycle it.
- */
-STATIC struct xfs_dquot *
-xfs_qm_dqreclaim_one(void)
+        mutex_lock(&qi->qi_dqlist_lock);
+        list_del_init(&dqp->q_mplist);
+        qi->qi_dquots--;
+        qi->qi_dqreclaims++;
+        mutex_unlock(&qi->qi_dqlist_lock);
+
+        xfs_qm_dqdestroy(dqp);
+}
+
+STATIC void
+xfs_qm_dqreclaim_one(
+        struct xfs_dquot        *dqp,
+        struct list_head        *dispose_list)
 {
-        struct xfs_dquot        *dqp;
-        int                     restarts = 0;
+        struct xfs_mount        *mp = dqp->q_mount;
+        int                     error;
 
-        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;
+        if (!xfs_dqlock_nowait(dqp))
+                goto out_busy;
 
-                if (!xfs_dqlock_nowait(dqp))
-                        continue;
+        /*
+         * This dquot has acquired a reference in the meantime remove it from
+         * the freelist and try again.
+         */
+        if (dqp->q_nrefs) {
+                xfs_dqunlock(dqp);
 
-                /*
-                 * 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;
-                }
+                trace_xfs_dqreclaim_want(dqp);
+                XQM_STATS_INC(xqmstats.xs_qm_dqwants);
 
-                ASSERT(dqp->q_hash);
-                ASSERT(!list_empty(&dqp->q_mplist));
+                list_del_init(&dqp->q_freelist);
+                xfs_Gqm->qm_dqfrlist_cnt--;
+                return;
+        }
 
-                /*
-                 * 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;
+        ASSERT(dqp->q_hash);
+        ASSERT(!list_empty(&dqp->q_mplist));
 
-                /*
-                 * 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)) {
-                        int     error;
+        /*
+         * 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;
 
-                        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.
+         */
+        if (XFS_DQ_IS_DIRTY(dqp)) {
+                trace_xfs_dqreclaim_dirty(dqp);
 
-                        /*
-                         * We flush it delayed write, so don't bother
-                         * releasing the freelist lock.
-                         */
-                        error = xfs_qm_dqflush(dqp, SYNC_TRYLOCK);
-                        if (error) {
-                                xfs_warn(mp, "%s: dquot %p flush failed",
-                                        __func__, dqp);
-                        }
-                        goto dqunlock;
+                /*
+                 * 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);
                 }
-                xfs_dqfunlock(dqp);
 
                 /*
-                 * Prevent lookup now that we are going to reclaim the dquot.
-                 * Once XFS_DQ_FREEING is set lookup won't touch the dquot,
-                 * thus we can drop the lock now.
+                 * 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);
+                goto out_busy;
+        }
+        xfs_dqfunlock(dqp);
 
-                ASSERT(dqp->q_nrefs == 0);
-                list_del_init(&dqp->q_freelist);
-                xfs_Gqm->qm_dqfrlist_cnt--;
+        /*
+         * Prevent lookups now that we are past the point of no return.
+         */
+        dqp->dq_flags |= XFS_DQ_FREEING;
+        xfs_dqunlock(dqp);
 
-                mutex_unlock(&xfs_Gqm->qm_dqfrlist_lock);
-                return dqp;
-dqunlock:
-                xfs_dqunlock(dqp);
-                if (restarts >= XFS_QM_RECLAIM_MAX_RESTARTS)
-                        break;
-                goto restart;
-        }
+        ASSERT(dqp->q_nrefs == 0);
+        list_move_tail(&dqp->q_freelist, dispose_list);
+        xfs_Gqm->qm_dqfrlist_cnt--;
 
-        mutex_unlock(&xfs_Gqm->qm_dqfrlist_lock);
-        return NULL;
-}
+        trace_xfs_dqreclaim_done(dqp);
+        XQM_STATS_INC(xqmstats.xs_qm_dqreclaims);
+        return;
 
-/*
- * 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;
+out_busy:
+        xfs_dqunlock(dqp);
 
-        if (howmany <= 0)
-                return 0;
+        /*
+         * 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);
 
-        while (nreclaimed < howmany) {
-                dqp = xfs_qm_dqreclaim_one();
-                if (!dqp)
-                        return nreclaimed;
-                xfs_qm_dqdestroy(dqp);
-                nreclaimed++;
-        }
-        return nreclaimed;
+        trace_xfs_dqreclaim_busy(dqp);
+        XQM_STATS_INC(xqmstats.xs_qm_dqreclaim_misses);
 }
 
-/*
- * 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;
+        LIST_HEAD               (dispose_list);
+        struct xfs_dquot        *dqp;
 
-        if (nfree <= ndqused && nfree < ndquot)
+        if ((sc->gfp_mask & (__GFP_FS|__GFP_WAIT)) != (__GFP_FS|__GFP_WAIT))
                 return 0;
+        if (!nr_to_scan)
+                goto out;
 
-        ndqused *= xfs_Gqm->qm_dqfree_ratio;    /* target # of free dquots */
-        n = nfree - ndqused - ndquot;           /* # over target */
-
-        return xfs_qm_shake_freelist(MAX(nfree, n));
-}
-
-
-/*------------------------------------------------------------------*/
-
-/*
- * 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;
-
-        /*
-         * 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);
+        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);
+                xfs_qm_dqreclaim_one(dqp, &dispose_list);
         }
+        mutex_unlock(&xfs_Gqm->qm_dqfrlist_lock);
 
-        /*
-         * 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;
+        while (!list_empty(&dispose_list)) {
+                dqp = list_first_entry(&dispose_list, struct xfs_dquot,
+                                       q_freelist);
+                list_del_init(&dqp->q_freelist);
+                xfs_qm_dqfree_one(dqp);
+        }
+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.