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724 lines
22 KiB
724 lines
22 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* net/sched/sch_hhf.c Heavy-Hitter Filter (HHF) |
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* |
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* Copyright (C) 2013 Terry Lam <[email protected]> |
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* Copyright (C) 2013 Nandita Dukkipati <[email protected]> |
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*/ |
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|
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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 <linux/siphash.h> |
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#include <net/pkt_sched.h> |
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#include <net/sock.h> |
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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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struct hhf_sched_data { |
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struct wdrr_bucket buckets[WDRR_BUCKET_CNT]; |
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siphash_key_t 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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|
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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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|
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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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|
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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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|
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if (list_empty(head)) |
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return NULL; |
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|
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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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|
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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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|
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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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|
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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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|
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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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|
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return flow; |
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} |
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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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|
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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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|
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/* Get hashed flow-id of the skb. */ |
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hash = skb_get_hash_perturb(skb, &q->perturbation); |
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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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bucket->head = skb->next; |
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skb_mark_not_on_list(skb); |
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return skb; |
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} |
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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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|
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static unsigned int hhf_drop(struct Qdisc *sch, struct sk_buff **to_free) |
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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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|
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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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|
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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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qdisc_qstats_backlog_dec(sch, skb); |
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qdisc_drop(skb, sch, to_free); |
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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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struct sk_buff **to_free) |
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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; |
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unsigned int prev_backlog; |
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|
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idx = hhf_classify(skb, sch); |
|
|
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bucket = &q->buckets[idx]; |
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bucket_add(bucket, skb); |
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qdisc_qstats_backlog_inc(sch, skb); |
|
|
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if (list_empty(&bucket->bucketchain)) { |
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unsigned int weight; |
|
|
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/* The logic of new_buckets vs. old_buckets is the same as |
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* new_flows vs. old_flows in the implementation of fq_codel, |
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* i.e., short bursts of non-HHs should have strict priority. |
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*/ |
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if (idx == WDRR_BUCKET_FOR_HH) { |
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/* Always move heavy-hitters to old bucket. */ |
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weight = 1; |
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list_add_tail(&bucket->bucketchain, &q->old_buckets); |
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} else { |
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weight = q->hhf_non_hh_weight; |
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list_add_tail(&bucket->bucketchain, &q->new_buckets); |
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} |
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bucket->deficit = weight * q->quantum; |
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} |
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if (++sch->q.qlen <= sch->limit) |
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return NET_XMIT_SUCCESS; |
|
|
|
prev_backlog = sch->qstats.backlog; |
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q->drop_overlimit++; |
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/* Return Congestion Notification only if we dropped a packet from this |
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* bucket. |
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*/ |
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if (hhf_drop(sch, to_free) == idx) |
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return NET_XMIT_CN; |
|
|
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/* As we dropped a packet, better let upper stack know this. */ |
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qdisc_tree_reduce_backlog(sch, 1, prev_backlog - sch->qstats.backlog); |
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return NET_XMIT_SUCCESS; |
|
} |
|
|
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static struct sk_buff *hhf_dequeue(struct Qdisc *sch) |
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{ |
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struct hhf_sched_data *q = qdisc_priv(sch); |
|
struct sk_buff *skb = NULL; |
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struct wdrr_bucket *bucket; |
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struct list_head *head; |
|
|
|
begin: |
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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) { |
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int weight = (bucket - q->buckets == WDRR_BUCKET_FOR_HH) ? |
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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--; |
|
qdisc_qstats_backlog_dec(sch, skb); |
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} |
|
|
|
if (!skb) { |
|
/* Force a pass through old_buckets to prevent starvation. */ |
|
if ((head == &q->new_buckets) && !list_empty(&q->old_buckets)) |
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list_move_tail(&bucket->bucketchain, &q->old_buckets); |
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else |
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list_del_init(&bucket->bucketchain); |
|
goto begin; |
|
} |
|
qdisc_bstats_update(sch, skb); |
|
bucket->deficit -= qdisc_pkt_len(skb); |
|
|
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return skb; |
|
} |
|
|
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static void hhf_reset(struct Qdisc *sch) |
|
{ |
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struct sk_buff *skb; |
|
|
|
while ((skb = hhf_dequeue(sch)) != NULL) |
|
rtnl_kfree_skbs(skb, skb); |
|
} |
|
|
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static void hhf_destroy(struct Qdisc *sch) |
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{ |
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int i; |
|
struct hhf_sched_data *q = qdisc_priv(sch); |
|
|
|
for (i = 0; i < HHF_ARRAYS_CNT; i++) { |
|
kvfree(q->hhf_arrays[i]); |
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kvfree(q->hhf_valid_bits[i]); |
|
} |
|
|
|
if (!q->hh_flows) |
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return; |
|
|
|
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); |
|
} |
|
} |
|
kvfree(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 netlink_ext_ack *extack) |
|
{ |
|
struct hhf_sched_data *q = qdisc_priv(sch); |
|
struct nlattr *tb[TCA_HHF_MAX + 1]; |
|
unsigned int qlen, prev_backlog; |
|
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_deprecated(tb, TCA_HHF_MAX, opt, hhf_policy, |
|
NULL); |
|
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 == 0 || 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; |
|
prev_backlog = sch->qstats.backlog; |
|
while (sch->q.qlen > sch->limit) { |
|
struct sk_buff *skb = hhf_dequeue(sch); |
|
|
|
rtnl_kfree_skbs(skb, skb); |
|
} |
|
qdisc_tree_reduce_backlog(sch, qlen - sch->q.qlen, |
|
prev_backlog - sch->qstats.backlog); |
|
|
|
sch_tree_unlock(sch); |
|
return 0; |
|
} |
|
|
|
static int hhf_init(struct Qdisc *sch, struct nlattr *opt, |
|
struct netlink_ext_ack *extack) |
|
{ |
|
struct hhf_sched_data *q = qdisc_priv(sch); |
|
int i; |
|
|
|
sch->limit = 1000; |
|
q->quantum = psched_mtu(qdisc_dev(sch)); |
|
get_random_bytes(&q->perturbation, sizeof(q->perturbation)); |
|
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, extack); |
|
|
|
if (err) |
|
return err; |
|
} |
|
|
|
if (!q->hh_flows) { |
|
/* Initialize heavy-hitter flow table. */ |
|
q->hh_flows = kvcalloc(HH_FLOWS_CNT, sizeof(struct list_head), |
|
GFP_KERNEL); |
|
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] = kvcalloc(HHF_ARRAYS_LEN, |
|
sizeof(u32), |
|
GFP_KERNEL); |
|
if (!q->hhf_arrays[i]) { |
|
/* Note: hhf_destroy() will be called |
|
* by our caller. |
|
*/ |
|
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] = kvzalloc(HHF_ARRAYS_LEN / |
|
BITS_PER_BYTE, GFP_KERNEL); |
|
if (!q->hhf_valid_bits[i]) { |
|
/* Note: hhf_destroy() will be called |
|
* by our caller. |
|
*/ |
|
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_noflag(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, |
|
.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"); |
|
MODULE_DESCRIPTION("Heavy-Hitter Filter (HHF)");
|
|
|