mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-11-25 04:50:57 +07:00
09c434b8a0
Add SPDX license identifiers to all files which:
- Have no license information of any form
- Have MODULE_LICENCE("GPL*") inside which was used in the initial
scan/conversion to ignore the file
These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:
GPL-2.0-only
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
348 lines
8.8 KiB
C
348 lines
8.8 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
/*
|
|
* TCP Low Priority (TCP-LP)
|
|
*
|
|
* TCP Low Priority is a distributed algorithm whose goal is to utilize only
|
|
* the excess network bandwidth as compared to the ``fair share`` of
|
|
* bandwidth as targeted by TCP.
|
|
*
|
|
* As of 2.6.13, Linux supports pluggable congestion control algorithms.
|
|
* Due to the limitation of the API, we take the following changes from
|
|
* the original TCP-LP implementation:
|
|
* o We use newReno in most core CA handling. Only add some checking
|
|
* within cong_avoid.
|
|
* o Error correcting in remote HZ, therefore remote HZ will be keeped
|
|
* on checking and updating.
|
|
* o Handling calculation of One-Way-Delay (OWD) within rtt_sample, since
|
|
* OWD have a similar meaning as RTT. Also correct the buggy formular.
|
|
* o Handle reaction for Early Congestion Indication (ECI) within
|
|
* pkts_acked, as mentioned within pseudo code.
|
|
* o OWD is handled in relative format, where local time stamp will in
|
|
* tcp_time_stamp format.
|
|
*
|
|
* Original Author:
|
|
* Aleksandar Kuzmanovic <akuzma@northwestern.edu>
|
|
* Available from:
|
|
* http://www.ece.rice.edu/~akuzma/Doc/akuzma/TCP-LP.pdf
|
|
* Original implementation for 2.4.19:
|
|
* http://www-ece.rice.edu/networks/TCP-LP/
|
|
*
|
|
* 2.6.x module Authors:
|
|
* Wong Hoi Sing, Edison <hswong3i@gmail.com>
|
|
* Hung Hing Lun, Mike <hlhung3i@gmail.com>
|
|
* SourceForge project page:
|
|
* http://tcp-lp-mod.sourceforge.net/
|
|
*/
|
|
|
|
#include <linux/module.h>
|
|
#include <net/tcp.h>
|
|
|
|
/* resolution of owd */
|
|
#define LP_RESOL TCP_TS_HZ
|
|
|
|
/**
|
|
* enum tcp_lp_state
|
|
* @LP_VALID_RHZ: is remote HZ valid?
|
|
* @LP_VALID_OWD: is OWD valid?
|
|
* @LP_WITHIN_THR: are we within threshold?
|
|
* @LP_WITHIN_INF: are we within inference?
|
|
*
|
|
* TCP-LP's state flags.
|
|
* We create this set of state flag mainly for debugging.
|
|
*/
|
|
enum tcp_lp_state {
|
|
LP_VALID_RHZ = (1 << 0),
|
|
LP_VALID_OWD = (1 << 1),
|
|
LP_WITHIN_THR = (1 << 3),
|
|
LP_WITHIN_INF = (1 << 4),
|
|
};
|
|
|
|
/**
|
|
* struct lp
|
|
* @flag: TCP-LP state flag
|
|
* @sowd: smoothed OWD << 3
|
|
* @owd_min: min OWD
|
|
* @owd_max: max OWD
|
|
* @owd_max_rsv: resrved max owd
|
|
* @remote_hz: estimated remote HZ
|
|
* @remote_ref_time: remote reference time
|
|
* @local_ref_time: local reference time
|
|
* @last_drop: time for last active drop
|
|
* @inference: current inference
|
|
*
|
|
* TCP-LP's private struct.
|
|
* We get the idea from original TCP-LP implementation where only left those we
|
|
* found are really useful.
|
|
*/
|
|
struct lp {
|
|
u32 flag;
|
|
u32 sowd;
|
|
u32 owd_min;
|
|
u32 owd_max;
|
|
u32 owd_max_rsv;
|
|
u32 remote_hz;
|
|
u32 remote_ref_time;
|
|
u32 local_ref_time;
|
|
u32 last_drop;
|
|
u32 inference;
|
|
};
|
|
|
|
/**
|
|
* tcp_lp_init
|
|
*
|
|
* Init all required variables.
|
|
* Clone the handling from Vegas module implementation.
|
|
*/
|
|
static void tcp_lp_init(struct sock *sk)
|
|
{
|
|
struct lp *lp = inet_csk_ca(sk);
|
|
|
|
lp->flag = 0;
|
|
lp->sowd = 0;
|
|
lp->owd_min = 0xffffffff;
|
|
lp->owd_max = 0;
|
|
lp->owd_max_rsv = 0;
|
|
lp->remote_hz = 0;
|
|
lp->remote_ref_time = 0;
|
|
lp->local_ref_time = 0;
|
|
lp->last_drop = 0;
|
|
lp->inference = 0;
|
|
}
|
|
|
|
/**
|
|
* tcp_lp_cong_avoid
|
|
*
|
|
* Implementation of cong_avoid.
|
|
* Will only call newReno CA when away from inference.
|
|
* From TCP-LP's paper, this will be handled in additive increasement.
|
|
*/
|
|
static void tcp_lp_cong_avoid(struct sock *sk, u32 ack, u32 acked)
|
|
{
|
|
struct lp *lp = inet_csk_ca(sk);
|
|
|
|
if (!(lp->flag & LP_WITHIN_INF))
|
|
tcp_reno_cong_avoid(sk, ack, acked);
|
|
}
|
|
|
|
/**
|
|
* tcp_lp_remote_hz_estimator
|
|
*
|
|
* Estimate remote HZ.
|
|
* We keep on updating the estimated value, where original TCP-LP
|
|
* implementation only guest it for once and use forever.
|
|
*/
|
|
static u32 tcp_lp_remote_hz_estimator(struct sock *sk)
|
|
{
|
|
struct tcp_sock *tp = tcp_sk(sk);
|
|
struct lp *lp = inet_csk_ca(sk);
|
|
s64 rhz = lp->remote_hz << 6; /* remote HZ << 6 */
|
|
s64 m = 0;
|
|
|
|
/* not yet record reference time
|
|
* go away!! record it before come back!! */
|
|
if (lp->remote_ref_time == 0 || lp->local_ref_time == 0)
|
|
goto out;
|
|
|
|
/* we can't calc remote HZ with no different!! */
|
|
if (tp->rx_opt.rcv_tsval == lp->remote_ref_time ||
|
|
tp->rx_opt.rcv_tsecr == lp->local_ref_time)
|
|
goto out;
|
|
|
|
m = TCP_TS_HZ *
|
|
(tp->rx_opt.rcv_tsval - lp->remote_ref_time) /
|
|
(tp->rx_opt.rcv_tsecr - lp->local_ref_time);
|
|
if (m < 0)
|
|
m = -m;
|
|
|
|
if (rhz > 0) {
|
|
m -= rhz >> 6; /* m is now error in remote HZ est */
|
|
rhz += m; /* 63/64 old + 1/64 new */
|
|
} else
|
|
rhz = m << 6;
|
|
|
|
out:
|
|
/* record time for successful remote HZ calc */
|
|
if ((rhz >> 6) > 0)
|
|
lp->flag |= LP_VALID_RHZ;
|
|
else
|
|
lp->flag &= ~LP_VALID_RHZ;
|
|
|
|
/* record reference time stamp */
|
|
lp->remote_ref_time = tp->rx_opt.rcv_tsval;
|
|
lp->local_ref_time = tp->rx_opt.rcv_tsecr;
|
|
|
|
return rhz >> 6;
|
|
}
|
|
|
|
/**
|
|
* tcp_lp_owd_calculator
|
|
*
|
|
* Calculate one way delay (in relative format).
|
|
* Original implement OWD as minus of remote time difference to local time
|
|
* difference directly. As this time difference just simply equal to RTT, when
|
|
* the network status is stable, remote RTT will equal to local RTT, and result
|
|
* OWD into zero.
|
|
* It seems to be a bug and so we fixed it.
|
|
*/
|
|
static u32 tcp_lp_owd_calculator(struct sock *sk)
|
|
{
|
|
struct tcp_sock *tp = tcp_sk(sk);
|
|
struct lp *lp = inet_csk_ca(sk);
|
|
s64 owd = 0;
|
|
|
|
lp->remote_hz = tcp_lp_remote_hz_estimator(sk);
|
|
|
|
if (lp->flag & LP_VALID_RHZ) {
|
|
owd =
|
|
tp->rx_opt.rcv_tsval * (LP_RESOL / lp->remote_hz) -
|
|
tp->rx_opt.rcv_tsecr * (LP_RESOL / TCP_TS_HZ);
|
|
if (owd < 0)
|
|
owd = -owd;
|
|
}
|
|
|
|
if (owd > 0)
|
|
lp->flag |= LP_VALID_OWD;
|
|
else
|
|
lp->flag &= ~LP_VALID_OWD;
|
|
|
|
return owd;
|
|
}
|
|
|
|
/**
|
|
* tcp_lp_rtt_sample
|
|
*
|
|
* Implementation or rtt_sample.
|
|
* Will take the following action,
|
|
* 1. calc OWD,
|
|
* 2. record the min/max OWD,
|
|
* 3. calc smoothed OWD (SOWD).
|
|
* Most ideas come from the original TCP-LP implementation.
|
|
*/
|
|
static void tcp_lp_rtt_sample(struct sock *sk, u32 rtt)
|
|
{
|
|
struct lp *lp = inet_csk_ca(sk);
|
|
s64 mowd = tcp_lp_owd_calculator(sk);
|
|
|
|
/* sorry that we don't have valid data */
|
|
if (!(lp->flag & LP_VALID_RHZ) || !(lp->flag & LP_VALID_OWD))
|
|
return;
|
|
|
|
/* record the next min owd */
|
|
if (mowd < lp->owd_min)
|
|
lp->owd_min = mowd;
|
|
|
|
/* always forget the max of the max
|
|
* we just set owd_max as one below it */
|
|
if (mowd > lp->owd_max) {
|
|
if (mowd > lp->owd_max_rsv) {
|
|
if (lp->owd_max_rsv == 0)
|
|
lp->owd_max = mowd;
|
|
else
|
|
lp->owd_max = lp->owd_max_rsv;
|
|
lp->owd_max_rsv = mowd;
|
|
} else
|
|
lp->owd_max = mowd;
|
|
}
|
|
|
|
/* calc for smoothed owd */
|
|
if (lp->sowd != 0) {
|
|
mowd -= lp->sowd >> 3; /* m is now error in owd est */
|
|
lp->sowd += mowd; /* owd = 7/8 owd + 1/8 new */
|
|
} else
|
|
lp->sowd = mowd << 3; /* take the measured time be owd */
|
|
}
|
|
|
|
/**
|
|
* tcp_lp_pkts_acked
|
|
*
|
|
* Implementation of pkts_acked.
|
|
* Deal with active drop under Early Congestion Indication.
|
|
* Only drop to half and 1 will be handle, because we hope to use back
|
|
* newReno in increase case.
|
|
* We work it out by following the idea from TCP-LP's paper directly
|
|
*/
|
|
static void tcp_lp_pkts_acked(struct sock *sk, const struct ack_sample *sample)
|
|
{
|
|
struct tcp_sock *tp = tcp_sk(sk);
|
|
struct lp *lp = inet_csk_ca(sk);
|
|
u32 now = tcp_time_stamp(tp);
|
|
u32 delta;
|
|
|
|
if (sample->rtt_us > 0)
|
|
tcp_lp_rtt_sample(sk, sample->rtt_us);
|
|
|
|
/* calc inference */
|
|
delta = now - tp->rx_opt.rcv_tsecr;
|
|
if ((s32)delta > 0)
|
|
lp->inference = 3 * delta;
|
|
|
|
/* test if within inference */
|
|
if (lp->last_drop && (now - lp->last_drop < lp->inference))
|
|
lp->flag |= LP_WITHIN_INF;
|
|
else
|
|
lp->flag &= ~LP_WITHIN_INF;
|
|
|
|
/* test if within threshold */
|
|
if (lp->sowd >> 3 <
|
|
lp->owd_min + 15 * (lp->owd_max - lp->owd_min) / 100)
|
|
lp->flag |= LP_WITHIN_THR;
|
|
else
|
|
lp->flag &= ~LP_WITHIN_THR;
|
|
|
|
pr_debug("TCP-LP: %05o|%5u|%5u|%15u|%15u|%15u\n", lp->flag,
|
|
tp->snd_cwnd, lp->remote_hz, lp->owd_min, lp->owd_max,
|
|
lp->sowd >> 3);
|
|
|
|
if (lp->flag & LP_WITHIN_THR)
|
|
return;
|
|
|
|
/* FIXME: try to reset owd_min and owd_max here
|
|
* so decrease the chance the min/max is no longer suitable
|
|
* and will usually within threshold when whithin inference */
|
|
lp->owd_min = lp->sowd >> 3;
|
|
lp->owd_max = lp->sowd >> 2;
|
|
lp->owd_max_rsv = lp->sowd >> 2;
|
|
|
|
/* happened within inference
|
|
* drop snd_cwnd into 1 */
|
|
if (lp->flag & LP_WITHIN_INF)
|
|
tp->snd_cwnd = 1U;
|
|
|
|
/* happened after inference
|
|
* cut snd_cwnd into half */
|
|
else
|
|
tp->snd_cwnd = max(tp->snd_cwnd >> 1U, 1U);
|
|
|
|
/* record this drop time */
|
|
lp->last_drop = now;
|
|
}
|
|
|
|
static struct tcp_congestion_ops tcp_lp __read_mostly = {
|
|
.init = tcp_lp_init,
|
|
.ssthresh = tcp_reno_ssthresh,
|
|
.undo_cwnd = tcp_reno_undo_cwnd,
|
|
.cong_avoid = tcp_lp_cong_avoid,
|
|
.pkts_acked = tcp_lp_pkts_acked,
|
|
|
|
.owner = THIS_MODULE,
|
|
.name = "lp"
|
|
};
|
|
|
|
static int __init tcp_lp_register(void)
|
|
{
|
|
BUILD_BUG_ON(sizeof(struct lp) > ICSK_CA_PRIV_SIZE);
|
|
return tcp_register_congestion_control(&tcp_lp);
|
|
}
|
|
|
|
static void __exit tcp_lp_unregister(void)
|
|
{
|
|
tcp_unregister_congestion_control(&tcp_lp);
|
|
}
|
|
|
|
module_init(tcp_lp_register);
|
|
module_exit(tcp_lp_unregister);
|
|
|
|
MODULE_AUTHOR("Wong Hoi Sing Edison, Hung Hing Lun Mike");
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_DESCRIPTION("TCP Low Priority");
|