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McKenney" , Tejun Heo , Barret Rhoden , Josh Don , Dohyun Kim , linux-arm-kernel@lists.infradead.org, kkd@meta.com, kernel-team@meta.com Subject: [PATCH bpf-next v3 19/25] bpf: Convert hashtab.c to rqspinlock Date: Mon, 3 Mar 2025 07:22:59 -0800 Message-ID: <20250303152305.3195648-20-memxor@gmail.com> X-Mailer: git-send-email 2.43.5 In-Reply-To: <20250303152305.3195648-1-memxor@gmail.com> References: <20250303152305.3195648-1-memxor@gmail.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=11131; h=from:subject; bh=4ih0G/0286de3X2HOwCgeQ8ZZwbokSdXkcTQRkadVk8=; b=owEBbQKS/ZANAwAIAUzgyIZIvxHKAcsmYgBnxcWYUEPdLFj8sZgqLb5zn7VbigpDGWSBgEbqM3XA x/fwLJeJAjMEAAEIAB0WIQRLvip+Buz51YI8YRFM4MiGSL8RygUCZ8XFmAAKCRBM4MiGSL8Ryv8LD/ 97jXIjkq7Lj++KTQTcQoBHp5m3OgRssDYOiFDubICyCP6RJL9F3I1YPvZ3V7aYFcJJBEuTYglkhD3z vdEzq0g+0G/b/2vgbS8q/Q6tlI4W54PihyS+qwGrnVz3uJPq2Vh8nK0kcPwLJzfLzM9O0weSfEcFz3 WN5AmPXgB759SWiegOPd5FlfEdvcgoDzQHqKNy5Oc4QGYqMMxfoe1BajpDdGIKckYE1k/Q3jD4Ika7 0Ocsr3XMKJdKzWaZ0++mS0Xg1WPgVlB28K08SYP/VcJv8ymSdntzx3T2FCD5ezdoG+8lXnrnhFKkSq JPUZizhxMzGDID+hebcv5VroikizRXHUOZP+OdlHq3FVRtQcu9YmttvUI/AYkCqVIlchD1WcW7nPg3 wBl+QpZfzhAmz3RlwPTacFVnw92AeQLJ/wEgyufOlTdQkFBwITR04JWL46ibiZugmnV5nF/HRctNPR z8cV3U0H2O39bk3dQ7m7Gb17vyUwD+31Bu/9WsIU+oFd9vj3uWEWCMCk7SbIHD+lTSHwZ9j90+KCKm 2aohPllCBBFhVPuDHR3hlKDDoNV1hA1lVZZIbepftZGRQYKUeoQQdxjHTha7P81H3VVeD0xhU+HmJN uqimoBk7BWk8BQ4E3HYoNBJ1UHaIZO4UP5kjM4Il4c+PzynID4cM955BCL0A== X-Developer-Key: i=memxor@gmail.com; a=openpgp; fpr=4BBE2A7E06ECF9D5823C61114CE0C88648BF11CA X-Patchwork-Delegate: bpf@iogearbox.net Convert hashtab.c from raw_spinlock to rqspinlock, and drop the hashed per-cpu counter crud from the code base which is no longer necessary. Closes: https://lore.kernel.org/bpf/675302fd.050a0220.2477f.0004.GAE@google.com Closes: https://lore.kernel.org/bpf/000000000000b3e63e061eed3f6b@google.com Signed-off-by: Kumar Kartikeya Dwivedi --- kernel/bpf/hashtab.c | 102 ++++++++++++++----------------------------- 1 file changed, 32 insertions(+), 70 deletions(-) diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c index c308300fc72f..93d45812bb6a 100644 --- a/kernel/bpf/hashtab.c +++ b/kernel/bpf/hashtab.c @@ -16,6 +16,7 @@ #include "bpf_lru_list.h" #include "map_in_map.h" #include +#include #define HTAB_CREATE_FLAG_MASK \ (BPF_F_NO_PREALLOC | BPF_F_NO_COMMON_LRU | BPF_F_NUMA_NODE | \ @@ -78,7 +79,7 @@ */ struct bucket { struct hlist_nulls_head head; - raw_spinlock_t raw_lock; + rqspinlock_t raw_lock; }; #define HASHTAB_MAP_LOCK_COUNT 8 @@ -104,8 +105,6 @@ struct bpf_htab { u32 n_buckets; /* number of hash buckets */ u32 elem_size; /* size of each element in bytes */ u32 hashrnd; - struct lock_class_key lockdep_key; - int __percpu *map_locked[HASHTAB_MAP_LOCK_COUNT]; }; /* each htab element is struct htab_elem + key + value */ @@ -140,45 +139,26 @@ static void htab_init_buckets(struct bpf_htab *htab) for (i = 0; i < htab->n_buckets; i++) { INIT_HLIST_NULLS_HEAD(&htab->buckets[i].head, i); - raw_spin_lock_init(&htab->buckets[i].raw_lock); - lockdep_set_class(&htab->buckets[i].raw_lock, - &htab->lockdep_key); + raw_res_spin_lock_init(&htab->buckets[i].raw_lock); cond_resched(); } } -static inline int htab_lock_bucket(const struct bpf_htab *htab, - struct bucket *b, u32 hash, - unsigned long *pflags) +static inline int htab_lock_bucket(struct bucket *b, unsigned long *pflags) { unsigned long flags; + int ret; - hash = hash & min_t(u32, HASHTAB_MAP_LOCK_MASK, htab->n_buckets - 1); - - preempt_disable(); - local_irq_save(flags); - if (unlikely(__this_cpu_inc_return(*(htab->map_locked[hash])) != 1)) { - __this_cpu_dec(*(htab->map_locked[hash])); - local_irq_restore(flags); - preempt_enable(); - return -EBUSY; - } - - raw_spin_lock(&b->raw_lock); + ret = raw_res_spin_lock_irqsave(&b->raw_lock, flags); + if (ret) + return ret; *pflags = flags; - return 0; } -static inline void htab_unlock_bucket(const struct bpf_htab *htab, - struct bucket *b, u32 hash, - unsigned long flags) +static inline void htab_unlock_bucket(struct bucket *b, unsigned long flags) { - hash = hash & min_t(u32, HASHTAB_MAP_LOCK_MASK, htab->n_buckets - 1); - raw_spin_unlock(&b->raw_lock); - __this_cpu_dec(*(htab->map_locked[hash])); - local_irq_restore(flags); - preempt_enable(); + raw_res_spin_unlock_irqrestore(&b->raw_lock, flags); } static bool htab_lru_map_delete_node(void *arg, struct bpf_lru_node *node); @@ -483,14 +463,12 @@ static struct bpf_map *htab_map_alloc(union bpf_attr *attr) bool percpu_lru = (attr->map_flags & BPF_F_NO_COMMON_LRU); bool prealloc = !(attr->map_flags & BPF_F_NO_PREALLOC); struct bpf_htab *htab; - int err, i; + int err; htab = bpf_map_area_alloc(sizeof(*htab), NUMA_NO_NODE); if (!htab) return ERR_PTR(-ENOMEM); - lockdep_register_key(&htab->lockdep_key); - bpf_map_init_from_attr(&htab->map, attr); if (percpu_lru) { @@ -536,15 +514,6 @@ static struct bpf_map *htab_map_alloc(union bpf_attr *attr) if (!htab->buckets) goto free_elem_count; - for (i = 0; i < HASHTAB_MAP_LOCK_COUNT; i++) { - htab->map_locked[i] = bpf_map_alloc_percpu(&htab->map, - sizeof(int), - sizeof(int), - GFP_USER); - if (!htab->map_locked[i]) - goto free_map_locked; - } - if (htab->map.map_flags & BPF_F_ZERO_SEED) htab->hashrnd = 0; else @@ -607,15 +576,12 @@ static struct bpf_map *htab_map_alloc(union bpf_attr *attr) free_map_locked: if (htab->use_percpu_counter) percpu_counter_destroy(&htab->pcount); - for (i = 0; i < HASHTAB_MAP_LOCK_COUNT; i++) - free_percpu(htab->map_locked[i]); bpf_map_area_free(htab->buckets); bpf_mem_alloc_destroy(&htab->pcpu_ma); bpf_mem_alloc_destroy(&htab->ma); free_elem_count: bpf_map_free_elem_count(&htab->map); free_htab: - lockdep_unregister_key(&htab->lockdep_key); bpf_map_area_free(htab); return ERR_PTR(err); } @@ -817,7 +783,7 @@ static bool htab_lru_map_delete_node(void *arg, struct bpf_lru_node *node) b = __select_bucket(htab, tgt_l->hash); head = &b->head; - ret = htab_lock_bucket(htab, b, tgt_l->hash, &flags); + ret = htab_lock_bucket(b, &flags); if (ret) return false; @@ -828,7 +794,7 @@ static bool htab_lru_map_delete_node(void *arg, struct bpf_lru_node *node) break; } - htab_unlock_bucket(htab, b, tgt_l->hash, flags); + htab_unlock_bucket(b, flags); if (l == tgt_l) check_and_free_fields(htab, l); @@ -1147,7 +1113,7 @@ static long htab_map_update_elem(struct bpf_map *map, void *key, void *value, */ } - ret = htab_lock_bucket(htab, b, hash, &flags); + ret = htab_lock_bucket(b, &flags); if (ret) return ret; @@ -1198,7 +1164,7 @@ static long htab_map_update_elem(struct bpf_map *map, void *key, void *value, check_and_free_fields(htab, l_old); } } - htab_unlock_bucket(htab, b, hash, flags); + htab_unlock_bucket(b, flags); if (l_old) { if (old_map_ptr) map->ops->map_fd_put_ptr(map, old_map_ptr, true); @@ -1207,7 +1173,7 @@ static long htab_map_update_elem(struct bpf_map *map, void *key, void *value, } return 0; err: - htab_unlock_bucket(htab, b, hash, flags); + htab_unlock_bucket(b, flags); return ret; } @@ -1254,7 +1220,7 @@ static long htab_lru_map_update_elem(struct bpf_map *map, void *key, void *value copy_map_value(&htab->map, l_new->key + round_up(map->key_size, 8), value); - ret = htab_lock_bucket(htab, b, hash, &flags); + ret = htab_lock_bucket(b, &flags); if (ret) goto err_lock_bucket; @@ -1275,7 +1241,7 @@ static long htab_lru_map_update_elem(struct bpf_map *map, void *key, void *value ret = 0; err: - htab_unlock_bucket(htab, b, hash, flags); + htab_unlock_bucket(b, flags); err_lock_bucket: if (ret) @@ -1312,7 +1278,7 @@ static long __htab_percpu_map_update_elem(struct bpf_map *map, void *key, b = __select_bucket(htab, hash); head = &b->head; - ret = htab_lock_bucket(htab, b, hash, &flags); + ret = htab_lock_bucket(b, &flags); if (ret) return ret; @@ -1337,7 +1303,7 @@ static long __htab_percpu_map_update_elem(struct bpf_map *map, void *key, } ret = 0; err: - htab_unlock_bucket(htab, b, hash, flags); + htab_unlock_bucket(b, flags); return ret; } @@ -1378,7 +1344,7 @@ static long __htab_lru_percpu_map_update_elem(struct bpf_map *map, void *key, return -ENOMEM; } - ret = htab_lock_bucket(htab, b, hash, &flags); + ret = htab_lock_bucket(b, &flags); if (ret) goto err_lock_bucket; @@ -1402,7 +1368,7 @@ static long __htab_lru_percpu_map_update_elem(struct bpf_map *map, void *key, } ret = 0; err: - htab_unlock_bucket(htab, b, hash, flags); + htab_unlock_bucket(b, flags); err_lock_bucket: if (l_new) { bpf_map_dec_elem_count(&htab->map); @@ -1444,7 +1410,7 @@ static long htab_map_delete_elem(struct bpf_map *map, void *key) b = __select_bucket(htab, hash); head = &b->head; - ret = htab_lock_bucket(htab, b, hash, &flags); + ret = htab_lock_bucket(b, &flags); if (ret) return ret; @@ -1454,7 +1420,7 @@ static long htab_map_delete_elem(struct bpf_map *map, void *key) else ret = -ENOENT; - htab_unlock_bucket(htab, b, hash, flags); + htab_unlock_bucket(b, flags); if (l) free_htab_elem(htab, l); @@ -1480,7 +1446,7 @@ static long htab_lru_map_delete_elem(struct bpf_map *map, void *key) b = __select_bucket(htab, hash); head = &b->head; - ret = htab_lock_bucket(htab, b, hash, &flags); + ret = htab_lock_bucket(b, &flags); if (ret) return ret; @@ -1491,7 +1457,7 @@ static long htab_lru_map_delete_elem(struct bpf_map *map, void *key) else ret = -ENOENT; - htab_unlock_bucket(htab, b, hash, flags); + htab_unlock_bucket(b, flags); if (l) htab_lru_push_free(htab, l); return ret; @@ -1558,7 +1524,6 @@ static void htab_map_free_timers_and_wq(struct bpf_map *map) static void htab_map_free(struct bpf_map *map) { struct bpf_htab *htab = container_of(map, struct bpf_htab, map); - int i; /* bpf_free_used_maps() or close(map_fd) will trigger this map_free callback. * bpf_free_used_maps() is called after bpf prog is no longer executing. @@ -1583,9 +1548,6 @@ static void htab_map_free(struct bpf_map *map) bpf_mem_alloc_destroy(&htab->ma); if (htab->use_percpu_counter) percpu_counter_destroy(&htab->pcount); - for (i = 0; i < HASHTAB_MAP_LOCK_COUNT; i++) - free_percpu(htab->map_locked[i]); - lockdep_unregister_key(&htab->lockdep_key); bpf_map_area_free(htab); } @@ -1628,7 +1590,7 @@ static int __htab_map_lookup_and_delete_elem(struct bpf_map *map, void *key, b = __select_bucket(htab, hash); head = &b->head; - ret = htab_lock_bucket(htab, b, hash, &bflags); + ret = htab_lock_bucket(b, &bflags); if (ret) return ret; @@ -1665,7 +1627,7 @@ static int __htab_map_lookup_and_delete_elem(struct bpf_map *map, void *key, hlist_nulls_del_rcu(&l->hash_node); out_unlock: - htab_unlock_bucket(htab, b, hash, bflags); + htab_unlock_bucket(b, bflags); if (l) { if (is_lru_map) @@ -1787,7 +1749,7 @@ __htab_map_lookup_and_delete_batch(struct bpf_map *map, head = &b->head; /* do not grab the lock unless need it (bucket_cnt > 0). */ if (locked) { - ret = htab_lock_bucket(htab, b, batch, &flags); + ret = htab_lock_bucket(b, &flags); if (ret) { rcu_read_unlock(); bpf_enable_instrumentation(); @@ -1810,7 +1772,7 @@ __htab_map_lookup_and_delete_batch(struct bpf_map *map, /* Note that since bucket_cnt > 0 here, it is implicit * that the locked was grabbed, so release it. */ - htab_unlock_bucket(htab, b, batch, flags); + htab_unlock_bucket(b, flags); rcu_read_unlock(); bpf_enable_instrumentation(); goto after_loop; @@ -1821,7 +1783,7 @@ __htab_map_lookup_and_delete_batch(struct bpf_map *map, /* Note that since bucket_cnt > 0 here, it is implicit * that the locked was grabbed, so release it. */ - htab_unlock_bucket(htab, b, batch, flags); + htab_unlock_bucket(b, flags); rcu_read_unlock(); bpf_enable_instrumentation(); kvfree(keys); @@ -1884,7 +1846,7 @@ __htab_map_lookup_and_delete_batch(struct bpf_map *map, dst_val += value_size; } - htab_unlock_bucket(htab, b, batch, flags); + htab_unlock_bucket(b, flags); locked = false; while (node_to_free) {