747 lines
22 KiB
C
747 lines
22 KiB
C
![]() |
/* net/sched/sch_hhf.c Heavy-Hitter Filter (HHF)
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*
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* Copyright (C) 2013 Terry Lam <vtlam@google.com>
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* Copyright (C) 2013 Nandita Dukkipati <nanditad@google.com>
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*/
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#include <linux/jhash.h>
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#include <linux/jiffies.h>
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#include <linux/module.h>
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#include <linux/skbuff.h>
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#include <linux/vmalloc.h>
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#include <net/flow_keys.h>
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#include <net/pkt_sched.h>
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#include <net/sock.h>
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/* Heavy-Hitter Filter (HHF)
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*
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* Principles :
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* Flows are classified into two buckets: non-heavy-hitter and heavy-hitter
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* buckets. Initially, a new flow starts as non-heavy-hitter. Once classified
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* as heavy-hitter, it is immediately switched to the heavy-hitter bucket.
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* The buckets are dequeued by a Weighted Deficit Round Robin (WDRR) scheduler,
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* in which the heavy-hitter bucket is served with less weight.
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* In other words, non-heavy-hitters (e.g., short bursts of critical traffic)
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* are isolated from heavy-hitters (e.g., persistent bulk traffic) and also have
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* higher share of bandwidth.
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*
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* To capture heavy-hitters, we use the "multi-stage filter" algorithm in the
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* following paper:
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* [EV02] C. Estan and G. Varghese, "New Directions in Traffic Measurement and
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* Accounting", in ACM SIGCOMM, 2002.
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*
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* Conceptually, a multi-stage filter comprises k independent hash functions
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* and k counter arrays. Packets are indexed into k counter arrays by k hash
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* functions, respectively. The counters are then increased by the packet sizes.
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* Therefore,
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* - For a heavy-hitter flow: *all* of its k array counters must be large.
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* - For a non-heavy-hitter flow: some of its k array counters can be large
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* due to hash collision with other small flows; however, with high
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* probability, not *all* k counters are large.
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*
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* By the design of the multi-stage filter algorithm, the false negative rate
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* (heavy-hitters getting away uncaptured) is zero. However, the algorithm is
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* susceptible to false positives (non-heavy-hitters mistakenly classified as
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* heavy-hitters).
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* Therefore, we also implement the following optimizations to reduce false
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* positives by avoiding unnecessary increment of the counter values:
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* - Optimization O1: once a heavy-hitter is identified, its bytes are not
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* accounted in the array counters. This technique is called "shielding"
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* in Section 3.3.1 of [EV02].
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* - Optimization O2: conservative update of counters
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* (Section 3.3.2 of [EV02]),
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* New counter value = max {old counter value,
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* smallest counter value + packet bytes}
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*
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* Finally, we refresh the counters periodically since otherwise the counter
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* values will keep accumulating.
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*
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* Once a flow is classified as heavy-hitter, we also save its per-flow state
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* in an exact-matching flow table so that its subsequent packets can be
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* dispatched to the heavy-hitter bucket accordingly.
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*
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*
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* At a high level, this qdisc works as follows:
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* Given a packet p:
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* - If the flow-id of p (e.g., TCP 5-tuple) is already in the exact-matching
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* heavy-hitter flow table, denoted table T, then send p to the heavy-hitter
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* bucket.
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* - Otherwise, forward p to the multi-stage filter, denoted filter F
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* + If F decides that p belongs to a non-heavy-hitter flow, then send p
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* to the non-heavy-hitter bucket.
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* + Otherwise, if F decides that p belongs to a new heavy-hitter flow,
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* then set up a new flow entry for the flow-id of p in the table T and
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* send p to the heavy-hitter bucket.
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*
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* In this implementation:
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* - T is a fixed-size hash-table with 1024 entries. Hash collision is
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* resolved by linked-list chaining.
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* - F has four counter arrays, each array containing 1024 32-bit counters.
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* That means 4 * 1024 * 32 bits = 16KB of memory.
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* - Since each array in F contains 1024 counters, 10 bits are sufficient to
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* index into each array.
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* Hence, instead of having four hash functions, we chop the 32-bit
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* skb-hash into three 10-bit chunks, and the remaining 10-bit chunk is
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* computed as XOR sum of those three chunks.
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* - We need to clear the counter arrays periodically; however, directly
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* memsetting 16KB of memory can lead to cache eviction and unwanted delay.
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* So by representing each counter by a valid bit, we only need to reset
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* 4K of 1 bit (i.e. 512 bytes) instead of 16KB of memory.
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* - The Deficit Round Robin engine is taken from fq_codel implementation
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* (net/sched/sch_fq_codel.c). Note that wdrr_bucket corresponds to
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* fq_codel_flow in fq_codel implementation.
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*
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*/
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/* Non-configurable parameters */
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#define HH_FLOWS_CNT 1024 /* number of entries in exact-matching table T */
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#define HHF_ARRAYS_CNT 4 /* number of arrays in multi-stage filter F */
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#define HHF_ARRAYS_LEN 1024 /* number of counters in each array of F */
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#define HHF_BIT_MASK_LEN 10 /* masking 10 bits */
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#define HHF_BIT_MASK 0x3FF /* bitmask of 10 bits */
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#define WDRR_BUCKET_CNT 2 /* two buckets for Weighted DRR */
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enum wdrr_bucket_idx {
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WDRR_BUCKET_FOR_HH = 0, /* bucket id for heavy-hitters */
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WDRR_BUCKET_FOR_NON_HH = 1 /* bucket id for non-heavy-hitters */
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};
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#define hhf_time_before(a, b) \
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(typecheck(u32, a) && typecheck(u32, b) && ((s32)((a) - (b)) < 0))
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/* Heavy-hitter per-flow state */
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struct hh_flow_state {
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u32 hash_id; /* hash of flow-id (e.g. TCP 5-tuple) */
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u32 hit_timestamp; /* last time heavy-hitter was seen */
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struct list_head flowchain; /* chaining under hash collision */
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};
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/* Weighted Deficit Round Robin (WDRR) scheduler */
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struct wdrr_bucket {
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struct sk_buff *head;
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struct sk_buff *tail;
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struct list_head bucketchain;
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int deficit;
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};
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struct hhf_sched_data {
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struct wdrr_bucket buckets[WDRR_BUCKET_CNT];
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u32 perturbation; /* hash perturbation */
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u32 quantum; /* psched_mtu(qdisc_dev(sch)); */
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u32 drop_overlimit; /* number of times max qdisc packet
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* limit was hit
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*/
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struct list_head *hh_flows; /* table T (currently active HHs) */
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u32 hh_flows_limit; /* max active HH allocs */
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u32 hh_flows_overlimit; /* num of disallowed HH allocs */
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u32 hh_flows_total_cnt; /* total admitted HHs */
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u32 hh_flows_current_cnt; /* total current HHs */
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u32 *hhf_arrays[HHF_ARRAYS_CNT]; /* HH filter F */
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u32 hhf_arrays_reset_timestamp; /* last time hhf_arrays
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* was reset
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*/
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unsigned long *hhf_valid_bits[HHF_ARRAYS_CNT]; /* shadow valid bits
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* of hhf_arrays
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*/
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/* Similar to the "new_flows" vs. "old_flows" concept in fq_codel DRR */
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struct list_head new_buckets; /* list of new buckets */
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struct list_head old_buckets; /* list of old buckets */
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/* Configurable HHF parameters */
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u32 hhf_reset_timeout; /* interval to reset counter
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* arrays in filter F
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* (default 40ms)
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*/
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u32 hhf_admit_bytes; /* counter thresh to classify as
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* HH (default 128KB).
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* With these default values,
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* 128KB / 40ms = 25 Mbps
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* i.e., we expect to capture HHs
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* sending > 25 Mbps.
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*/
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u32 hhf_evict_timeout; /* aging threshold to evict idle
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* HHs out of table T. This should
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* be large enough to avoid
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* reordering during HH eviction.
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* (default 1s)
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*/
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u32 hhf_non_hh_weight; /* WDRR weight for non-HHs
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* (default 2,
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* i.e., non-HH : HH = 2 : 1)
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*/
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};
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static u32 hhf_time_stamp(void)
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{
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return jiffies;
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}
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static unsigned int skb_hash(const struct hhf_sched_data *q,
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const struct sk_buff *skb)
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{
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struct flow_keys keys;
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unsigned int hash;
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if (skb->sk && skb->sk->sk_hash)
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return skb->sk->sk_hash;
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skb_flow_dissect(skb, &keys);
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hash = jhash_3words((__force u32)keys.dst,
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(__force u32)keys.src ^ keys.ip_proto,
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(__force u32)keys.ports, q->perturbation);
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return hash;
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}
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/* Looks up a heavy-hitter flow in a chaining list of table T. */
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static struct hh_flow_state *seek_list(const u32 hash,
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struct list_head *head,
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struct hhf_sched_data *q)
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{
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struct hh_flow_state *flow, *next;
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u32 now = hhf_time_stamp();
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if (list_empty(head))
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return NULL;
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list_for_each_entry_safe(flow, next, head, flowchain) {
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u32 prev = flow->hit_timestamp + q->hhf_evict_timeout;
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if (hhf_time_before(prev, now)) {
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/* Delete expired heavy-hitters, but preserve one entry
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* to avoid kzalloc() when next time this slot is hit.
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*/
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if (list_is_last(&flow->flowchain, head))
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return NULL;
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list_del(&flow->flowchain);
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kfree(flow);
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q->hh_flows_current_cnt--;
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} else if (flow->hash_id == hash) {
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return flow;
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}
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}
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return NULL;
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}
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/* Returns a flow state entry for a new heavy-hitter. Either reuses an expired
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* entry or dynamically alloc a new entry.
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*/
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static struct hh_flow_state *alloc_new_hh(struct list_head *head,
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struct hhf_sched_data *q)
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{
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struct hh_flow_state *flow;
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u32 now = hhf_time_stamp();
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if (!list_empty(head)) {
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/* Find an expired heavy-hitter flow entry. */
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list_for_each_entry(flow, head, flowchain) {
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u32 prev = flow->hit_timestamp + q->hhf_evict_timeout;
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if (hhf_time_before(prev, now))
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return flow;
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}
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}
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if (q->hh_flows_current_cnt >= q->hh_flows_limit) {
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q->hh_flows_overlimit++;
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return NULL;
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}
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/* Create new entry. */
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flow = kzalloc(sizeof(struct hh_flow_state), GFP_ATOMIC);
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if (!flow)
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return NULL;
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q->hh_flows_current_cnt++;
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INIT_LIST_HEAD(&flow->flowchain);
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list_add_tail(&flow->flowchain, head);
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return flow;
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}
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/* Assigns packets to WDRR buckets. Implements a multi-stage filter to
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* classify heavy-hitters.
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*/
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static enum wdrr_bucket_idx hhf_classify(struct sk_buff *skb, struct Qdisc *sch)
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{
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struct hhf_sched_data *q = qdisc_priv(sch);
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u32 tmp_hash, hash;
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u32 xorsum, filter_pos[HHF_ARRAYS_CNT], flow_pos;
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struct hh_flow_state *flow;
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u32 pkt_len, min_hhf_val;
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int i;
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u32 prev;
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u32 now = hhf_time_stamp();
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/* Reset the HHF counter arrays if this is the right time. */
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prev = q->hhf_arrays_reset_timestamp + q->hhf_reset_timeout;
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if (hhf_time_before(prev, now)) {
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for (i = 0; i < HHF_ARRAYS_CNT; i++)
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bitmap_zero(q->hhf_valid_bits[i], HHF_ARRAYS_LEN);
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q->hhf_arrays_reset_timestamp = now;
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}
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/* Get hashed flow-id of the skb. */
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hash = skb_hash(q, skb);
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/* Check if this packet belongs to an already established HH flow. */
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flow_pos = hash & HHF_BIT_MASK;
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flow = seek_list(hash, &q->hh_flows[flow_pos], q);
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if (flow) { /* found its HH flow */
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flow->hit_timestamp = now;
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return WDRR_BUCKET_FOR_HH;
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}
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/* Now pass the packet through the multi-stage filter. */
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tmp_hash = hash;
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xorsum = 0;
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for (i = 0; i < HHF_ARRAYS_CNT - 1; i++) {
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/* Split the skb_hash into three 10-bit chunks. */
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filter_pos[i] = tmp_hash & HHF_BIT_MASK;
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xorsum ^= filter_pos[i];
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tmp_hash >>= HHF_BIT_MASK_LEN;
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}
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/* The last chunk is computed as XOR sum of other chunks. */
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filter_pos[HHF_ARRAYS_CNT - 1] = xorsum ^ tmp_hash;
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pkt_len = qdisc_pkt_len(skb);
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min_hhf_val = ~0U;
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for (i = 0; i < HHF_ARRAYS_CNT; i++) {
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u32 val;
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if (!test_bit(filter_pos[i], q->hhf_valid_bits[i])) {
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q->hhf_arrays[i][filter_pos[i]] = 0;
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__set_bit(filter_pos[i], q->hhf_valid_bits[i]);
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}
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val = q->hhf_arrays[i][filter_pos[i]] + pkt_len;
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if (min_hhf_val > val)
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min_hhf_val = val;
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}
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/* Found a new HH iff all counter values > HH admit threshold. */
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if (min_hhf_val > q->hhf_admit_bytes) {
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/* Just captured a new heavy-hitter. */
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flow = alloc_new_hh(&q->hh_flows[flow_pos], q);
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if (!flow) /* memory alloc problem */
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return WDRR_BUCKET_FOR_NON_HH;
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flow->hash_id = hash;
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flow->hit_timestamp = now;
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q->hh_flows_total_cnt++;
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/* By returning without updating counters in q->hhf_arrays,
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* we implicitly implement "shielding" (see Optimization O1).
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*/
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return WDRR_BUCKET_FOR_HH;
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}
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/* Conservative update of HHF arrays (see Optimization O2). */
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for (i = 0; i < HHF_ARRAYS_CNT; i++) {
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if (q->hhf_arrays[i][filter_pos[i]] < min_hhf_val)
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q->hhf_arrays[i][filter_pos[i]] = min_hhf_val;
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}
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return WDRR_BUCKET_FOR_NON_HH;
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}
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/* Removes one skb from head of bucket. */
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static struct sk_buff *dequeue_head(struct wdrr_bucket *bucket)
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{
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struct sk_buff *skb = bucket->head;
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bucket->head = skb->next;
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skb->next = NULL;
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return skb;
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}
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/* Tail-adds skb to bucket. */
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static void bucket_add(struct wdrr_bucket *bucket, struct sk_buff *skb)
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{
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if (bucket->head == NULL)
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bucket->head = skb;
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else
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bucket->tail->next = skb;
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bucket->tail = skb;
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skb->next = NULL;
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}
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static unsigned int hhf_drop(struct Qdisc *sch)
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{
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struct hhf_sched_data *q = qdisc_priv(sch);
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struct wdrr_bucket *bucket;
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/* Always try to drop from heavy-hitters first. */
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bucket = &q->buckets[WDRR_BUCKET_FOR_HH];
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if (!bucket->head)
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bucket = &q->buckets[WDRR_BUCKET_FOR_NON_HH];
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if (bucket->head) {
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struct sk_buff *skb = dequeue_head(bucket);
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sch->q.qlen--;
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sch->qstats.drops++;
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sch->qstats.backlog -= qdisc_pkt_len(skb);
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kfree_skb(skb);
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}
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/* Return id of the bucket from which the packet was dropped. */
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return bucket - q->buckets;
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}
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static int hhf_enqueue(struct sk_buff *skb, struct Qdisc *sch)
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{
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struct hhf_sched_data *q = qdisc_priv(sch);
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enum wdrr_bucket_idx idx;
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||
|
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");
|