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/* SPDX-License-Identifier: GPL-2.0-only */
#ifndef __NET_SCHED_PIE_H
#define __NET_SCHED_PIE_H
#include <linux/ktime.h>
#include <linux/skbuff.h>
#include <linux/types.h>
#include <net/inet_ecn.h>
#include <net/pkt_sched.h>
#define MAX_PROB U64_MAX
#define DTIME_INVALID U64_MAX
#define QUEUE_THRESHOLD 16384
#define DQCOUNT_INVALID -1
#define PIE_SCALE 8
/* parameters used */
struct pie_params {
psched_time_t target; /* user specified target delay in pschedtime */
u32 tupdate; /* timer frequency (in jiffies) */
u32 limit; /* number of packets that can be enqueued */
u32 alpha; /* alpha and beta are between 0 and 32 */
u32 beta; /* and are used for shift relative to 1 */
bool ecn; /* true if ecn is enabled */
bool bytemode; /* to scale drop early prob based on pkt size */
u8 dq_rate_estimator; /* to calculate delay using Little's law */
};
/* variables used */
struct pie_vars {
u64 prob; /* probability but scaled by u64 limit. */
psched_time_t burst_time;
psched_time_t qdelay;
psched_time_t qdelay_old;
u64 dq_count; /* measured in bytes */
psched_time_t dq_tstamp; /* drain rate */
u64 accu_prob; /* accumulated drop probability */
u32 avg_dq_rate; /* bytes per pschedtime tick,scaled */
u32 qlen_old; /* in bytes */
u8 accu_prob_overflows; /* overflows of accu_prob */
};
/* statistics gathering */
struct pie_stats {
u32 packets_in; /* total number of packets enqueued */
u32 dropped; /* packets dropped due to pie_action */
u32 overlimit; /* dropped due to lack of space in queue */
u32 maxq; /* maximum queue size */
u32 ecn_mark; /* packets marked with ECN */
};
/* private skb vars */
struct pie_skb_cb {
psched_time_t enqueue_time;
};
static inline void pie_params_init(struct pie_params *params)
{
params->alpha = 2;
params->beta = 20;
params->tupdate = usecs_to_jiffies(15 * USEC_PER_MSEC); /* 15 ms */
params->limit = 1000; /* default of 1000 packets */
params->target = PSCHED_NS2TICKS(15 * NSEC_PER_MSEC); /* 15 ms */
params->ecn = false;
params->bytemode = false;
params->dq_rate_estimator = false;
}
static inline void pie_vars_init(struct pie_vars *vars)
{
vars->dq_count = DQCOUNT_INVALID;
vars->dq_tstamp = DTIME_INVALID;
vars->accu_prob = 0;
vars->avg_dq_rate = 0;
/* default of 150 ms in pschedtime */
vars->burst_time = PSCHED_NS2TICKS(150 * NSEC_PER_MSEC);
vars->accu_prob_overflows = 0;
}
static inline struct pie_skb_cb *get_pie_cb(const struct sk_buff *skb)
{
qdisc_cb_private_validate(skb, sizeof(struct pie_skb_cb));
return (struct pie_skb_cb *)qdisc_skb_cb(skb)->data;
}
static inline psched_time_t pie_get_enqueue_time(const struct sk_buff *skb)
{
return get_pie_cb(skb)->enqueue_time;
}
static inline void pie_set_enqueue_time(struct sk_buff *skb)
{
get_pie_cb(skb)->enqueue_time = psched_get_time();
}
#endif
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