diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/rhashtable.c | 62 | ||||
| -rw-r--r-- | lib/test_rhashtable.c | 11 |
2 files changed, 36 insertions, 37 deletions
diff --git a/lib/rhashtable.c b/lib/rhashtable.c index 9cc4c4a..b5344ef 100644 --- a/lib/rhashtable.c +++ b/lib/rhashtable.c @@ -17,6 +17,7 @@ #include <linux/kernel.h> #include <linux/init.h> #include <linux/log2.h> +#include <linux/sched.h> #include <linux/slab.h> #include <linux/vmalloc.h> #include <linux/mm.h> @@ -217,15 +218,15 @@ static void bucket_table_free(const struct bucket_table *tbl) static struct bucket_table *bucket_table_alloc(struct rhashtable *ht, size_t nbuckets) { - struct bucket_table *tbl; + struct bucket_table *tbl = NULL; size_t size; int i; size = sizeof(*tbl) + nbuckets * sizeof(tbl->buckets[0]); - tbl = kzalloc(size, GFP_KERNEL | __GFP_NOWARN); + if (size <= (PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER)) + tbl = kzalloc(size, GFP_KERNEL | __GFP_NOWARN | __GFP_NORETRY); if (tbl == NULL) tbl = vzalloc(size); - if (tbl == NULL) return NULL; @@ -247,26 +248,24 @@ static struct bucket_table *bucket_table_alloc(struct rhashtable *ht, * @ht: hash table * @new_size: new table size */ -bool rht_grow_above_75(const struct rhashtable *ht, size_t new_size) +static bool rht_grow_above_75(const struct rhashtable *ht, size_t new_size) { /* Expand table when exceeding 75% load */ return atomic_read(&ht->nelems) > (new_size / 4 * 3) && - (ht->p.max_shift && atomic_read(&ht->shift) < ht->p.max_shift); + (!ht->p.max_shift || atomic_read(&ht->shift) < ht->p.max_shift); } -EXPORT_SYMBOL_GPL(rht_grow_above_75); /** * rht_shrink_below_30 - returns true if nelems < 0.3 * table-size * @ht: hash table * @new_size: new table size */ -bool rht_shrink_below_30(const struct rhashtable *ht, size_t new_size) +static bool rht_shrink_below_30(const struct rhashtable *ht, size_t new_size) { /* Shrink table beneath 30% load */ return atomic_read(&ht->nelems) < (new_size * 3 / 10) && (atomic_read(&ht->shift) > ht->p.min_shift); } -EXPORT_SYMBOL_GPL(rht_shrink_below_30); static void lock_buckets(struct bucket_table *new_tbl, struct bucket_table *old_tbl, unsigned int hash) @@ -414,6 +413,7 @@ int rhashtable_expand(struct rhashtable *ht) } } unlock_buckets(new_tbl, old_tbl, new_hash); + cond_resched(); } /* Unzip interleaved hash chains */ @@ -437,6 +437,7 @@ int rhashtable_expand(struct rhashtable *ht) complete = false; unlock_buckets(new_tbl, old_tbl, old_hash); + cond_resched(); } } @@ -495,6 +496,7 @@ int rhashtable_shrink(struct rhashtable *ht) tbl->buckets[new_hash + new_tbl->size]); unlock_buckets(new_tbl, tbl, new_hash); + cond_resched(); } /* Publish the new, valid hash table */ @@ -528,31 +530,19 @@ static void rht_deferred_worker(struct work_struct *work) list_for_each_entry(walker, &ht->walkers, list) walker->resize = true; - if (ht->p.grow_decision && ht->p.grow_decision(ht, tbl->size)) + if (rht_grow_above_75(ht, tbl->size)) rhashtable_expand(ht); - else if (ht->p.shrink_decision && ht->p.shrink_decision(ht, tbl->size)) + else if (rht_shrink_below_30(ht, tbl->size)) rhashtable_shrink(ht); - unlock: mutex_unlock(&ht->mutex); } -static void rhashtable_wakeup_worker(struct rhashtable *ht) -{ - struct bucket_table *tbl = rht_dereference_rcu(ht->tbl, ht); - struct bucket_table *new_tbl = rht_dereference_rcu(ht->future_tbl, ht); - size_t size = tbl->size; - - /* Only adjust the table if no resizing is currently in progress. */ - if (tbl == new_tbl && - ((ht->p.grow_decision && ht->p.grow_decision(ht, size)) || - (ht->p.shrink_decision && ht->p.shrink_decision(ht, size)))) - schedule_work(&ht->run_work); -} - static void __rhashtable_insert(struct rhashtable *ht, struct rhash_head *obj, - struct bucket_table *tbl, u32 hash) + struct bucket_table *tbl, + const struct bucket_table *old_tbl, u32 hash) { + bool no_resize_running = tbl == old_tbl; struct rhash_head *head; hash = rht_bucket_index(tbl, hash); @@ -568,8 +558,8 @@ static void __rhashtable_insert(struct rhashtable *ht, struct rhash_head *obj, rcu_assign_pointer(tbl->buckets[hash], obj); atomic_inc(&ht->nelems); - - rhashtable_wakeup_worker(ht); + if (no_resize_running && rht_grow_above_75(ht, tbl->size)) + schedule_work(&ht->run_work); } /** @@ -599,7 +589,7 @@ void rhashtable_insert(struct rhashtable *ht, struct rhash_head *obj) hash = obj_raw_hashfn(ht, rht_obj(ht, obj)); lock_buckets(tbl, old_tbl, hash); - __rhashtable_insert(ht, obj, tbl, hash); + __rhashtable_insert(ht, obj, tbl, old_tbl, hash); unlock_buckets(tbl, old_tbl, hash); rcu_read_unlock(); @@ -681,8 +671,11 @@ found: unlock_buckets(new_tbl, old_tbl, new_hash); if (ret) { + bool no_resize_running = new_tbl == old_tbl; + atomic_dec(&ht->nelems); - rhashtable_wakeup_worker(ht); + if (no_resize_running && rht_shrink_below_30(ht, new_tbl->size)) + schedule_work(&ht->run_work); } rcu_read_unlock(); @@ -852,7 +845,7 @@ bool rhashtable_lookup_compare_insert(struct rhashtable *ht, goto exit; } - __rhashtable_insert(ht, obj, new_tbl, new_hash); + __rhashtable_insert(ht, obj, new_tbl, old_tbl, new_hash); exit: unlock_buckets(new_tbl, old_tbl, new_hash); @@ -894,6 +887,9 @@ int rhashtable_walk_init(struct rhashtable *ht, struct rhashtable_iter *iter) if (!iter->walker) return -ENOMEM; + INIT_LIST_HEAD(&iter->walker->list); + iter->walker->resize = false; + mutex_lock(&ht->mutex); list_add(&iter->walker->list, &ht->walkers); mutex_unlock(&ht->mutex); @@ -1111,8 +1107,7 @@ int rhashtable_init(struct rhashtable *ht, struct rhashtable_params *params) if (!ht->p.hash_rnd) get_random_bytes(&ht->p.hash_rnd, sizeof(ht->p.hash_rnd)); - if (ht->p.grow_decision || ht->p.shrink_decision) - INIT_WORK(&ht->run_work, rht_deferred_worker); + INIT_WORK(&ht->run_work, rht_deferred_worker); return 0; } @@ -1130,8 +1125,7 @@ void rhashtable_destroy(struct rhashtable *ht) { ht->being_destroyed = true; - if (ht->p.grow_decision || ht->p.shrink_decision) - cancel_work_sync(&ht->run_work); + cancel_work_sync(&ht->run_work); mutex_lock(&ht->mutex); bucket_table_free(rht_dereference(ht->tbl, ht)); diff --git a/lib/test_rhashtable.c b/lib/test_rhashtable.c index 1dfeba7..67c7593 100644 --- a/lib/test_rhashtable.c +++ b/lib/test_rhashtable.c @@ -191,18 +191,18 @@ error: return err; } +static struct rhashtable ht; + static int __init test_rht_init(void) { - struct rhashtable ht; struct rhashtable_params params = { .nelem_hint = TEST_HT_SIZE, .head_offset = offsetof(struct test_obj, node), .key_offset = offsetof(struct test_obj, value), .key_len = sizeof(int), .hashfn = jhash, + .max_shift = 1, /* we expand/shrink manually here */ .nulls_base = (3U << RHT_BASE_SHIFT), - .grow_decision = rht_grow_above_75, - .shrink_decision = rht_shrink_below_30, }; int err; @@ -222,6 +222,11 @@ static int __init test_rht_init(void) return err; } +static void __exit test_rht_exit(void) +{ +} + module_init(test_rht_init); +module_exit(test_rht_exit); MODULE_LICENSE("GPL v2"); |
