diff options
| -rw-r--r-- | include/uapi/linux/pkt_sched.h | 25 | ||||
| -rw-r--r-- | net/sched/Kconfig | 9 | ||||
| -rw-r--r-- | net/sched/Makefile | 1 | ||||
| -rw-r--r-- | net/sched/sch_hhf.c | 746 |
4 files changed, 781 insertions, 0 deletions
diff --git a/include/uapi/linux/pkt_sched.h b/include/uapi/linux/pkt_sched.h index a806687ad98f..4566993b8385 100644 --- a/include/uapi/linux/pkt_sched.h +++ b/include/uapi/linux/pkt_sched.h @@ -790,4 +790,29 @@ struct tc_fq_qd_stats { __u32 throttled_flows; __u32 pad; }; + +/* Heavy-Hitter Filter */ + +enum { + TCA_HHF_UNSPEC, + TCA_HHF_BACKLOG_LIMIT, + TCA_HHF_QUANTUM, + TCA_HHF_HH_FLOWS_LIMIT, + TCA_HHF_RESET_TIMEOUT, + TCA_HHF_ADMIT_BYTES, + TCA_HHF_EVICT_TIMEOUT, + TCA_HHF_NON_HH_WEIGHT, + __TCA_HHF_MAX +}; + +#define TCA_HHF_MAX (__TCA_HHF_MAX - 1) + +struct tc_hhf_xstats { + __u32 drop_overlimit; /* number of times max qdisc packet limit + * was hit + */ + __u32 hh_overlimit; /* number of times max heavy-hitters was hit */ + __u32 hh_tot_count; /* number of captured heavy-hitters so far */ + __u32 hh_cur_count; /* number of current heavy-hitters */ +}; #endif diff --git a/net/sched/Kconfig b/net/sched/Kconfig index ad1f1d819203..919847beec39 100644 --- a/net/sched/Kconfig +++ b/net/sched/Kconfig @@ -286,6 +286,15 @@ config NET_SCH_FQ If unsure, say N. +config NET_SCH_HHF + tristate "Heavy-Hitter Filter (HHF)" + help + Say Y here if you want to use the Heavy-Hitter Filter (HHF) + packet scheduling algorithm. + + To compile this driver as a module, choose M here: the module + will be called sch_hhf. + config NET_SCH_INGRESS tristate "Ingress Qdisc" depends on NET_CLS_ACT diff --git a/net/sched/Makefile b/net/sched/Makefile index 35fa47a494ab..3442e5fbc4d7 100644 --- a/net/sched/Makefile +++ b/net/sched/Makefile @@ -40,6 +40,7 @@ obj-$(CONFIG_NET_SCH_QFQ) += sch_qfq.o obj-$(CONFIG_NET_SCH_CODEL) += sch_codel.o obj-$(CONFIG_NET_SCH_FQ_CODEL) += sch_fq_codel.o obj-$(CONFIG_NET_SCH_FQ) += sch_fq.o +obj-$(CONFIG_NET_SCH_HHF) += sch_hhf.o obj-$(CONFIG_NET_CLS_U32) += cls_u32.o obj-$(CONFIG_NET_CLS_ROUTE4) += cls_route.o diff --git a/net/sched/sch_hhf.c b/net/sched/sch_hhf.c new file mode 100644 index 000000000000..97aa33dbb90f --- /dev/null +++ b/net/sched/sch_hhf.c @@ -0,0 +1,746 @@ +/* net/sched/sch_hhf.c Heavy-Hitter Filter (HHF) + * + * Copyright (C) 2013 Terry Lam <vtlam@google.com> + * Copyright (C) 2013 Nandita Dukkipati <nanditad@google.com> + */ + +#include <linux/jhash.h> +#include <linux/jiffies.h> +#include <linux/module.h> +#include <linux/skbuff.h> +#include <linux/vmalloc.h> +#include <net/flow_keys.h> +#include <net/pkt_sched.h> +#include <net/sock.h> + +/* Heavy-Hitter Filter (HHF) + * + * Principles : + * Flows are classified into two buckets: non-heavy-hitter and heavy-hitter + * buckets. Initially, a new flow starts as non-heavy-hitter. Once classified + * as heavy-hitter, it is immediately switched to the heavy-hitter bucket. + * The buckets are dequeued by a Weighted Deficit Round Robin (WDRR) scheduler, + * in which the heavy-hitter bucket is served with less weight. + * In other words, non-heavy-hitters (e.g., short bursts of critical traffic) + * are isolated from heavy-hitters (e.g., persistent bulk traffic) and also have + * higher share of bandwidth. + * + * To capture heavy-hitters, we use the "multi-stage filter" algorithm in the + * following paper: + * [EV02] C. Estan and G. Varghese, "New Directions in Traffic Measurement and + * Accounting", in ACM SIGCOMM, 2002. + * + * Conceptually, a multi-stage filter comprises k independent hash functions + * and k counter arrays. Packets are indexed into k counter arrays by k hash + * functions, respectively. The counters are then increased by the packet sizes. + * Therefore, + * - For a heavy-hitter flow: *all* of its k array counters must be large. + * - For a non-heavy-hitter flow: some of its k array counters can be large + * due to hash collision with other small flows; however, with high + * probability, not *all* k counters are large. + * + * By the design of the multi-stage filter algorithm, the false negative rate + * (heavy-hitters getting away uncaptured) is zero. However, the algorithm is + * susceptible to false positives (non-heavy-hitters mistakenly classified as + * heavy-hitters). + * Therefore, we also implement the following optimizations to reduce false + * positives by avoiding unnecessary increment of the counter values: + * - Optimization O1: once a heavy-hitter is identified, its bytes are not + * accounted in the array counters. This technique is called "shielding" + * in Section 3.3.1 of [EV02]. + * - Optimization O2: conservative update of counters + * (Section 3.3.2 of [EV02]), + * New counter value = max {old counter value, + * smallest counter value + packet bytes} + * + * Finally, we refresh the counters periodically since otherwise the counter + * values will keep accumulating. + * + * Once a flow is classified as heavy-hitter, we also save its per-flow state + * in an exact-matching flow table so that its subsequent packets can be + * dispatched to the heavy-hitter bucket accordingly. + * + * + * At a high level, this qdisc works as follows: + * Given a packet p: + * - If the flow-id of p (e.g., TCP 5-tuple) is already in the exact-matching + * heavy-hitter flow table, denoted table T, then send p to the heavy-hitter + * bucket. + * - Otherwise, forward p to the multi-stage filter, denoted filter F + * + If F decides that p belongs to a non-heavy-hitter flow, then send p + * to the non-heavy-hitter bucket. + * + Otherwise, if F decides that p belongs to a new heavy-hitter flow, + * then set up a new flow entry for the flow-id of p in the table T and + * send p to the heavy-hitter bucket. + * + * In this implementation: + * - T is a fixed-size hash-table with 1024 entries. Hash collision is + * resolved by linked-list chaining. + * - F has four counter arrays, each array containing 1024 32-bit counters. + * That means 4 * 1024 * 32 bits = 16KB of memory. + * - Since each array in F contains 1024 counters, 10 bits are sufficient to + * index into each array. + * Hence, instead of having four hash functions, we chop the 32-bit + * skb-hash into three 10-bit chunks, and the remaining 10-bit chunk is + * computed as XOR sum of those three chunks. + * - We need to clear the counter arrays periodically; however, directly + * memsetting 16KB of memory can lead to cache eviction and unwanted delay. + * So by representing each counter by a valid bit, we only need to reset + * 4K of 1 bit (i.e. 512 bytes) instead of 16KB of memory. + * - The Deficit Round Robin engine is taken from fq_codel implementation + * (net/sched/sch_fq_codel.c). Note that wdrr_bucket corresponds to + * fq_codel_flow in fq_codel implementation. + * + */ + +/* Non-configurable parameters */ +#define HH_FLOWS_CNT 1024 /* number of entries in exact-matching table T */ +#define HHF_ARRAYS_CNT 4 /* number of arrays in multi-stage filter F */ +#define HHF_ARRAYS_LEN 1024 /* number of counters in each array of F */ +#define HHF_BIT_MASK_LEN 10 /* masking 10 bits */ +#define HHF_BIT_MASK 0x3FF /* bitmask of 10 bits */ + +#define WDRR_BUCKET_CNT 2 /* two buckets for Weighted DRR */ +enum wdrr_bucket_idx { + WDRR_BUCKET_FOR_HH = 0, /* bucket id for heavy-hitters */ + WDRR_BUCKET_FOR_NON_HH = 1 /* bucket id for non-heavy-hitters */ +}; + +#define hhf_time_before(a, b) \ + (typecheck(u32, a) && typecheck(u32, b) && ((s32)((a) - (b)) < 0)) + +/* Heavy-hitter per-flow state */ +struct hh_flow_state { + u32 hash_id; /* hash of flow-id (e.g. TCP 5-tuple) */ + u32 hit_timestamp; /* last time heavy-hitter was seen */ + struct list_head flowchain; /* chaining under hash collision */ +}; + +/* Weighted Deficit Round Robin (WDRR) scheduler */ +struct wdrr_bucket { + struct sk_buff *head; + struct sk_buff *tail; + struct list_head bucketchain; + int deficit; +}; + +struct hhf_sched_data { + struct wdrr_bucket buckets[WDRR_BUCKET_CNT]; + u32 perturbation; /* hash perturbation */ + u32 quantum; /* psched_mtu(qdisc_dev(sch)); */ + u32 drop_overlimit; /* number of times max qdisc packet + * limit was hit + */ + struct list_head *hh_flows; /* table T (currently active HHs) */ + u32 hh_flows_limit; /* max active HH allocs */ + u32 hh_flows_overlimit; /* num of disallowed HH allocs */ + u32 hh_flows_total_cnt; /* total admitted HHs */ + u32 hh_flows_current_cnt; /* total current HHs */ + u32 *hhf_arrays[HHF_ARRAYS_CNT]; /* HH filter F */ + u32 hhf_arrays_reset_timestamp; /* last time hhf_arrays + * was reset + */ + unsigned long *hhf_valid_bits[HHF_ARRAYS_CNT]; /* shadow valid bits + * of hhf_arrays + */ + /* Similar to the "new_flows" vs. "old_flows" concept in fq_codel DRR */ + struct list_head new_buckets; /* list of new buckets */ + struct list_head old_buckets; /* list of old buckets */ + + /* Configurable HHF parameters */ + u32 hhf_reset_timeout; /* interval to reset counter + * arrays in filter F + * (default 40ms) + */ + u32 hhf_admit_bytes; /* counter thresh to classify as + * HH (default 128KB). + * With these default values, + * 128KB / 40ms = 25 Mbps + * i.e., we expect to capture HHs + * sending > 25 Mbps. + */ + u32 hhf_evict_timeout; /* aging threshold to evict idle + * HHs out of table T. This should + * be large enough to avoid + * reordering during HH eviction. + * (default 1s) + */ + u32 hhf_non_hh_weight; /* WDRR weight for non-HHs + * (default 2, + * i.e., non-HH : HH = 2 : 1) + */ +}; + +static u32 hhf_time_stamp(void) +{ + return jiffies; +} + +static unsigned int skb_hash(const struct hhf_sched_data *q, + const struct sk_buff *skb) +{ + struct flow_keys keys; + unsigned int hash; + + if (skb->sk && skb->sk->sk_hash) + return skb->sk->sk_hash; + + skb_flow_dissect(skb, &keys); + hash = jhash_3words((__force u32)keys.dst, + (__force u32)keys.src ^ keys.ip_proto, + (__force u32)keys.ports, q->perturbation); + return hash; +} + +/* Looks up a heavy-hitter flow in a chaining list of table T. */ +static struct hh_flow_state *seek_list(const u32 hash, + struct list_head *head, + struct hhf_sched_data *q) +{ + struct hh_flow_state *flow, *next; + u32 now = hhf_time_stamp(); + + if (list_empty(head)) + return NULL; + + list_for_each_entry_safe(flow, next, head, flowchain) { + u32 prev = flow->hit_timestamp + q->hhf_evict_timeout; + + if (hhf_time_before(prev, now)) { + /* Delete expired heavy-hitters, but preserve one entry + * to avoid kzalloc() when next time this slot is hit. + */ + if (list_is_last(&flow->flowchain, head)) + return NULL; + list_del(&flow->flowchain); + kfree(flow); + q->hh_flows_current_cnt--; + } else if (flow->hash_id == hash) { + return flow; + } + } + return NULL; +} + +/* Returns a flow state entry for a new heavy-hitter. Either reuses an expired + * entry or dynamically alloc a new entry. + */ +static struct hh_flow_state *alloc_new_hh(struct list_head *head, + struct hhf_sched_data *q) +{ + struct hh_flow_state *flow; + u32 now = hhf_time_stamp(); + + if (!list_empty(head)) { + /* Find an expired heavy-hitter flow entry. */ + list_for_each_entry(flow, head, flowchain) { + u32 prev = flow->hit_timestamp + q->hhf_evict_timeout; + + if (hhf_time_before(prev, now)) + return flow; + } + } + + if (q->hh_flows_current_cnt >= q->hh_flows_limit) { + q->hh_flows_overlimit++; + return NULL; + } + /* Create new entry. */ + flow = kzalloc(sizeof(struct hh_flow_state), GFP_ATOMIC); + if (!flow) + return NULL; + + q->hh_flows_current_cnt++; + INIT_LIST_HEAD(&flow->flowchain); + list_add_tail(&flow->flowchain, head); + + return flow; +} + +/* Assigns packets to WDRR buckets. Implements a multi-stage filter to + * classify heavy-hitters. + */ +static enum wdrr_bucket_idx hhf_classify(struct sk_buff *skb, struct Qdisc *sch) +{ + struct hhf_sched_data *q = qdisc_priv(sch); + u32 tmp_hash, hash; + u32 xorsum, filter_pos[HHF_ARRAYS_CNT], flow_pos; + struct hh_flow_state *flow; + u32 pkt_len, min_hhf_val; + int i; + u32 prev; + u32 now = hhf_time_stamp(); + + /* Reset the HHF counter arrays if this is the right time. */ + prev = q->hhf_arrays_reset_timestamp + q->hhf_reset_timeout; + if (hhf_time_before(prev, now)) { + for (i = 0; i < HHF_ARRAYS_CNT; i++) + bitmap_zero(q->hhf_valid_bits[i], HHF_ARRAYS_LEN); + q->hhf_arrays_reset_timestamp = now; + } + + /* Get hashed flow-id of the skb. */ + hash = skb_hash(q, skb); + + /* Check if this packet belongs to an already established HH flow. */ + flow_pos = hash & HHF_BIT_MASK; + flow = seek_list(hash, &q->hh_flows[flow_pos], q); + if (flow) { /* found its HH flow */ + flow->hit_timestamp = now; + return WDRR_BUCKET_FOR_HH; + } + + /* Now pass the packet through the multi-stage filter. */ + tmp_hash = hash; + xorsum = 0; + for (i = 0; i < HHF_ARRAYS_CNT - 1; i++) { + /* Split the skb_hash into three 10-bit chunks. */ + filter_pos[i] = tmp_hash & HHF_BIT_MASK; + xorsum ^= filter_pos[i]; + tmp_hash >>= HHF_BIT_MASK_LEN; + } + /* The last chunk is computed as XOR sum of other chunks. */ + filter_pos[HHF_ARRAYS_CNT - 1] = xorsum ^ tmp_hash; + + pkt_len = qdisc_pkt_len(skb); + min_hhf_val = ~0U; + for (i = 0; i < HHF_ARRAYS_CNT; i++) { + u32 val; + + if (!test_bit(filter_pos[i], q->hhf_valid_bits[i])) { + q->hhf_arrays[i][filter_pos[i]] = 0; + __set_bit(filter_pos[i], q->hhf_valid_bits[i]); + } + + val = q->hhf_arrays[i][filter_pos[i]] + pkt_len; + if (min_hhf_val > val) + min_hhf_val = val; + } + + /* Found a new HH iff all counter values > HH admit threshold. */ + if (min_hhf_val > q->hhf_admit_bytes) { + /* Just captured a new heavy-hitter. */ + flow = alloc_new_hh(&q->hh_flows[flow_pos], q); + if (!flow) /* memory alloc problem */ + return WDRR_BUCKET_FOR_NON_HH; + flow->hash_id = hash; + flow->hit_timestamp = now; + q->hh_flows_total_cnt++; + + /* By returning without updating counters in q->hhf_arrays, + * we implicitly implement "shielding" (see Optimization O1). + */ + return WDRR_BUCKET_FOR_HH; + } + + /* Conservative update of HHF arrays (see Optimization O2). */ + for (i = 0; i < HHF_ARRAYS_CNT; i++) { + if (q->hhf_arrays[i][filter_pos[i]] < min_hhf_val) + q->hhf_arrays[i][filter_pos[i]] = min_hhf_val; + } + return WDRR_BUCKET_FOR_NON_HH; +} + +/* Removes one skb from head of bucket. */ +static struct sk_buff *dequeue_head(struct wdrr_bucket *bucket) +{ + struct sk_buff *skb = bucket->head; + + bucket->head = skb->next; + skb->next = NULL; + return skb; +} + +/* Tail-adds skb to bucket. */ +static void bucket_add(struct wdrr_bucket *bucket, struct sk_buff *skb) +{ + if (bucket->head == NULL) + bucket->head = skb; + else + bucket->tail->next = skb; + bucket->tail = skb; + skb->next = NULL; +} + +static unsigned int hhf_drop(struct Qdisc *sch) +{ + struct hhf_sched_data *q = qdisc_priv(sch); + struct wdrr_bucket *bucket; + + /* Always try to drop from heavy-hitters first. */ + bucket = &q->buckets[WDRR_BUCKET_FOR_HH]; + if (!bucket->head) + bucket = &q->buckets[WDRR_BUCKET_FOR_NON_HH]; + + if (bucket->head) { + struct sk_buff *skb = dequeue_head(bucket); + + sch->q.qlen--; + sch->qstats.drops++; + sch->qstats.backlog -= qdisc_pkt_len(skb); + kfree_skb(skb); + } + + /* Return id of the bucket from which the packet was dropped. */ + return bucket - q->buckets; +} + +static int hhf_enqueue(struct sk_buff *skb, struct Qdisc *sch) +{ + struct hhf_sched_data *q = qdisc_priv(sch); + enum wdrr_bucket_idx idx; + struct wdrr_bucket *bucket; + + idx = hhf_classify(skb, sch); + + bucket = &q->buckets[idx]; + bucket_add(bucket, skb); + sch->qstats.backlog += qdisc_pkt_len(skb); + + if (list_empty(&bucket->bucketchain)) { + unsigned int weight; + + /* The logic of new_buckets vs. old_buckets is the same as + * new_flows vs. old_flows in the implementation of fq_codel, + * i.e., short bursts of non-HHs should have strict priority. + */ + if (idx == WDRR_BUCKET_FOR_HH) { + /* Always move heavy-hitters to old bucket. */ + weight = 1; + list_add_tail(&bucket->bucketchain, &q->old_buckets); + } else { + weight = q->hhf_non_hh_weight; + list_add_tail(&bucket->bucketchain, &q->new_buckets); + } + bucket->deficit = weight * q->quantum; + } + if (++sch->q.qlen < sch->limit) + return NET_XMIT_SUCCESS; + + q->drop_overlimit++; + /* Return Congestion Notification only if we dropped a packet from this + * bucket. + */ + if (hhf_drop(sch) == idx) + return NET_XMIT_CN; + + /* As we dropped a packet, better let upper stack know this. */ + qdisc_tree_decrease_qlen(sch, 1); + return NET_XMIT_SUCCESS; +} + +static struct sk_buff *hhf_dequeue(struct Qdisc *sch) +{ + struct hhf_sched_data *q = qdisc_priv(sch); + struct sk_buff *skb = NULL; + struct wdrr_bucket *bucket; + struct list_head *head; + +begin: + head = &q->new_buckets; + if (list_empty(head)) { + head = &q->old_buckets; + if (list_empty(head)) + return NULL; + } + bucket = list_first_entry(head, struct wdrr_bucket, bucketchain); + + if (bucket->deficit <= 0) { + int weight = (bucket - q->buckets == WDRR_BUCKET_FOR_HH) ? + 1 : q->hhf_non_hh_weight; + + bucket->deficit += weight * q->quantum; + list_move_tail(&bucket->bucketchain, &q->old_buckets); + goto begin; + } + + if (bucket->head) { + skb = dequeue_head(bucket); + sch->q.qlen--; + sch->qstats.backlog -= qdisc_pkt_len(skb); + } + + if (!skb) { + /* Force a pass through old_buckets to prevent starvation. */ + if ((head == &q->new_buckets) && !list_empty(&q->old_buckets)) + list_move_tail(&bucket->bucketchain, &q->old_buckets); + else + list_del_init(&bucket->bucketchain); + goto begin; + } + qdisc_bstats_update(sch, skb); + bucket->deficit -= qdisc_pkt_len(skb); + + return skb; +} + +static void hhf_reset(struct Qdisc *sch) +{ + struct sk_buff *skb; + + while ((skb = hhf_dequeue(sch)) != NULL) + kfree_skb(skb); +} + +static void *hhf_zalloc(size_t sz) +{ + void *ptr = kzalloc(sz, GFP_KERNEL | __GFP_NOWARN); + + if (!ptr) + ptr = vzalloc(sz); + + return ptr; +} + +static void hhf_free(void *addr) +{ + if (addr) { + if (is_vmalloc_addr(addr)) + vfree(addr); + else + kfree(addr); + } +} + +static void hhf_destroy(struct Qdisc *sch) +{ + int i; + struct hhf_sched_data *q = qdisc_priv(sch); + + for (i = 0; i < HHF_ARRAYS_CNT; i++) { + hhf_free(q->hhf_arrays[i]); + hhf_free(q->hhf_valid_bits[i]); + } + + for (i = 0; i < HH_FLOWS_CNT; i++) { + struct hh_flow_state *flow, *next; + struct list_head *head = &q->hh_flows[i]; + + if (list_empty(head)) + continue; + list_for_each_entry_safe(flow, next, head, flowchain) { + list_del(&flow->flowchain); + kfree(flow); + } + } + hhf_free(q->hh_flows); +} + +static const struct nla_policy hhf_policy[TCA_HHF_MAX + 1] = { + [TCA_HHF_BACKLOG_LIMIT] = { .type = NLA_U32 }, + [TCA_HHF_QUANTUM] = { .type = NLA_U32 }, + [TCA_HHF_HH_FLOWS_LIMIT] = { .type = NLA_U32 }, + [TCA_HHF_RESET_TIMEOUT] = { .type = NLA_U32 }, + [TCA_HHF_ADMIT_BYTES] = { .type = NLA_U32 }, + [TCA_HHF_EVICT_TIMEOUT] = { .type = NLA_U32 }, + [TCA_HHF_NON_HH_WEIGHT] = { .type = NLA_U32 }, +}; + +static int hhf_change(struct Qdisc *sch, struct nlattr *opt) +{ + struct hhf_sched_data *q = qdisc_priv(sch); + struct nlattr *tb[TCA_HHF_MAX + 1]; + unsigned int qlen; + int err; + u64 non_hh_quantum; + u32 new_quantum = q->quantum; + u32 new_hhf_non_hh_weight = q->hhf_non_hh_weight; + + if (!opt) + return -EINVAL; + + err = nla_parse_nested(tb, TCA_HHF_MAX, opt, hhf_policy); + if (err < 0) + return err; + + sch_tree_lock(sch); + + if (tb[TCA_HHF_BACKLOG_LIMIT]) + sch->limit = nla_get_u32(tb[TCA_HHF_BACKLOG_LIMIT]); + + if (tb[TCA_HHF_QUANTUM]) + new_quantum = nla_get_u32(tb[TCA_HHF_QUANTUM]); + + if (tb[TCA_HHF_NON_HH_WEIGHT]) + new_hhf_non_hh_weight = nla_get_u32(tb[TCA_HHF_NON_HH_WEIGHT]); + + non_hh_quantum = (u64)new_quantum * new_hhf_non_hh_weight; + if (non_hh_quantum > INT_MAX) + return -EINVAL; + q->quantum = new_quantum; + q->hhf_non_hh_weight = new_hhf_non_hh_weight; + + if (tb[TCA_HHF_HH_FLOWS_LIMIT]) + q->hh_flows_limit = nla_get_u32(tb[TCA_HHF_HH_FLOWS_LIMIT]); + + if (tb[TCA_HHF_RESET_TIMEOUT]) { + u32 ms = nla_get_u32(tb[TCA_HHF_RESET_TIMEOUT]); + + q->hhf_reset_timeout = msecs_to_jiffies(ms); + } + + if (tb[TCA_HHF_ADMIT_BYTES]) + q->hhf_admit_bytes = nla_get_u32(tb[TCA_HHF_ADMIT_BYTES]); + + if (tb[TCA_HHF_EVICT_TIMEOUT]) { + u32 ms = nla_get_u32(tb[TCA_HHF_EVICT_TIMEOUT]); + + q->hhf_evict_timeout = msecs_to_jiffies(ms); + } + + qlen = sch->q.qlen; + while (sch->q.qlen > sch->limit) { + struct sk_buff *skb = hhf_dequeue(sch); + + kfree_skb(skb); + } + qdisc_tree_decrease_qlen(sch, qlen - sch->q.qlen); + + sch_tree_unlock(sch); + return 0; +} + +static int hhf_init(struct Qdisc *sch, struct nlattr *opt) +{ + struct hhf_sched_data *q = qdisc_priv(sch); + int i; + + sch->limit = 1000; + q->quantum = psched_mtu(qdisc_dev(sch)); + q->perturbation = net_random(); + INIT_LIST_HEAD(&q->new_buckets); + INIT_LIST_HEAD(&q->old_buckets); + + /* Configurable HHF parameters */ + q->hhf_reset_timeout = HZ / 25; /* 40 ms */ + q->hhf_admit_bytes = 131072; /* 128 KB */ + q->hhf_evict_timeout = HZ; /* 1 sec */ + q->hhf_non_hh_weight = 2; + + if (opt) { + int err = hhf_change(sch, opt); + + if (err) + return err; + } + + if (!q->hh_flows) { + /* Initialize heavy-hitter flow table. */ + q->hh_flows = hhf_zalloc(HH_FLOWS_CNT * + sizeof(struct list_head)); + if (!q->hh_flows) + return -ENOMEM; + for (i = 0; i < HH_FLOWS_CNT; i++) + INIT_LIST_HEAD(&q->hh_flows[i]); + + /* Cap max active HHs at twice len of hh_flows table. */ + q->hh_flows_limit = 2 * HH_FLOWS_CNT; + q->hh_flows_overlimit = 0; + q->hh_flows_total_cnt = 0; + q->hh_flows_current_cnt = 0; + + /* Initialize heavy-hitter filter arrays. */ + for (i = 0; i < HHF_ARRAYS_CNT; i++) { + q->hhf_arrays[i] = hhf_zalloc(HHF_ARRAYS_LEN * + sizeof(u32)); + if (!q->hhf_arrays[i]) { + hhf_destroy(sch); + return -ENOMEM; + } + } + q->hhf_arrays_reset_timestamp = hhf_time_stamp(); + + /* Initialize valid bits of heavy-hitter filter arrays. */ + for (i = 0; i < HHF_ARRAYS_CNT; i++) { + q->hhf_valid_bits[i] = hhf_zalloc(HHF_ARRAYS_LEN / + BITS_PER_BYTE); + if (!q->hhf_valid_bits[i]) { + hhf_destroy(sch); + return -ENOMEM; + } + } + + /* Initialize Weighted DRR buckets. */ + for (i = 0; i < WDRR_BUCKET_CNT; i++) { + struct wdrr_bucket *bucket = q->buckets + i; + + INIT_LIST_HEAD(&bucket->bucketchain); + } + } + + return 0; +} + +static int hhf_dump(struct Qdisc *sch, struct sk_buff *skb) +{ + struct hhf_sched_data *q = qdisc_priv(sch); + struct nlattr *opts; + + opts = nla_nest_start(skb, TCA_OPTIONS); + if (opts == NULL) + goto nla_put_failure; + + if (nla_put_u32(skb, TCA_HHF_BACKLOG_LIMIT, sch->limit) || + nla_put_u32(skb, TCA_HHF_QUANTUM, q->quantum) || + nla_put_u32(skb, TCA_HHF_HH_FLOWS_LIMIT, q->hh_flows_limit) || + nla_put_u32(skb, TCA_HHF_RESET_TIMEOUT, + jiffies_to_msecs(q->hhf_reset_timeout)) || + nla_put_u32(skb, TCA_HHF_ADMIT_BYTES, q->hhf_admit_bytes) || + nla_put_u32(skb, TCA_HHF_EVICT_TIMEOUT, + jiffies_to_msecs(q->hhf_evict_timeout)) || + nla_put_u32(skb, TCA_HHF_NON_HH_WEIGHT, q->hhf_non_hh_weight)) + goto nla_put_failure; + + nla_nest_end(skb, opts); + return skb->len; + +nla_put_failure: + return -1; +} + +static int hhf_dump_stats(struct Qdisc *sch, struct gnet_dump *d) +{ + struct hhf_sched_data *q = qdisc_priv(sch); + struct tc_hhf_xstats st = { + .drop_overlimit = q->drop_overlimit, + .hh_overlimit = q->hh_flows_overlimit, + .hh_tot_count = q->hh_flows_total_cnt, + .hh_cur_count = q->hh_flows_current_cnt, + }; + + return gnet_stats_copy_app(d, &st, sizeof(st)); +} + +struct Qdisc_ops hhf_qdisc_ops __read_mostly = { + .id = "hhf", + .priv_size = sizeof(struct hhf_sched_data), + + .enqueue = hhf_enqueue, + .dequeue = hhf_dequeue, + .peek = qdisc_peek_dequeued, + .drop = hhf_drop, + .init = hhf_init, + .reset = hhf_reset, + .destroy = hhf_destroy, + .change = hhf_change, + .dump = hhf_dump, + .dump_stats = hhf_dump_stats, + .owner = THIS_MODULE, +}; +EXPORT_SYMBOL(hhf_qdisc_ops); + +static int __init hhf_module_init(void) +{ + return register_qdisc(&hhf_qdisc_ops); +} + +static void __exit hhf_module_exit(void) +{ + unregister_qdisc(&hhf_qdisc_ops); +} + +module_init(hhf_module_init) +module_exit(hhf_module_exit) +MODULE_AUTHOR("Terry Lam"); +MODULE_AUTHOR("Nandita Dukkipati"); +MODULE_LICENSE("GPL"); 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