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-rw-r--r--net/sched/sch_hhf.c740
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diff --git a/net/sched/sch_hhf.c b/net/sched/sch_hhf.c
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+/* 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)
+{
+ kvfree(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;
+
+ 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;
+
+ sch_tree_lock(sch);
+
+ if (tb[TCA_HHF_BACKLOG_LIMIT])
+ sch->limit = nla_get_u32(tb[TCA_HHF_BACKLOG_LIMIT]);
+
+ 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 us = nla_get_u32(tb[TCA_HHF_RESET_TIMEOUT]);
+
+ q->hhf_reset_timeout = usecs_to_jiffies(us);
+ }
+
+ 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 us = nla_get_u32(tb[TCA_HHF_EVICT_TIMEOUT]);
+
+ q->hhf_evict_timeout = usecs_to_jiffies(us);
+ }
+
+ 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 = prandom_u32();
+ 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_usecs(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_usecs(q->hhf_evict_timeout)) ||
+ nla_put_u32(skb, TCA_HHF_NON_HH_WEIGHT, q->hhf_non_hh_weight))
+ goto nla_put_failure;
+
+ return nla_nest_end(skb, opts);
+
+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));
+}
+
+static 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,
+};
+
+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");
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2025-11-04 07:47:39 +0000