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classq_fq_codel.c
557 lines (488 loc) · 14.2 KB
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classq_fq_codel.c
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/*
* Copyright (c) 2016-2020 Apple Inc. All rights reserved.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
*
* This file contains Original Code and/or Modifications of Original Code
* as defined in and that are subject to the Apple Public Source License
* Version 2.0 (the 'License'). You may not use this file except in
* compliance with the License. The rights granted to you under the License
* may not be used to create, or enable the creation or redistribution of,
* unlawful or unlicensed copies of an Apple operating system, or to
* circumvent, violate, or enable the circumvention or violation of, any
* terms of an Apple operating system software license agreement.
*
* Please obtain a copy of the License at
* http://www.opensource.apple.com/apsl/ and read it before using this file.
*
* The Original Code and all software distributed under the License are
* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
* Please see the License for the specific language governing rights and
* limitations under the License.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
*/
#include <sys/cdefs.h>
#include <sys/param.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/sockio.h>
#include <sys/systm.h>
#include <sys/sysctl.h>
#include <sys/syslog.h>
#include <sys/proc.h>
#include <sys/errno.h>
#include <sys/kernel.h>
#include <sys/kauth.h>
#include <sys/sdt.h>
#include <kern/zalloc.h>
#include <netinet/in.h>
#include <net/classq/classq.h>
#include <net/classq/if_classq.h>
#include <net/pktsched/pktsched.h>
#include <net/pktsched/pktsched_fq_codel.h>
#include <net/classq/classq_fq_codel.h>
#include <netinet/tcp_var.h>
static uint32_t flowq_size; /* size of flowq */
static struct mcache *flowq_cache = NULL; /* mcache for flowq */
#define FQ_ZONE_MAX (32 * 1024) /* across all interfaces */
#define DTYPE_NODROP 0 /* no drop */
#define DTYPE_FORCED 1 /* a "forced" drop */
#define DTYPE_EARLY 2 /* an "unforced" (early) drop */
void
fq_codel_init(void)
{
if (flowq_cache != NULL) {
return;
}
flowq_size = sizeof(fq_t);
flowq_cache = mcache_create("fq.flowq", flowq_size, sizeof(uint64_t),
0, MCR_SLEEP);
if (flowq_cache == NULL) {
panic("%s: failed to allocate flowq_cache", __func__);
/* NOTREACHED */
__builtin_unreachable();
}
}
void
fq_codel_reap_caches(boolean_t purge)
{
mcache_reap_now(flowq_cache, purge);
}
fq_t *
fq_alloc(classq_pkt_type_t ptype)
{
fq_t *fq = NULL;
fq = mcache_alloc(flowq_cache, MCR_SLEEP);
if (fq == NULL) {
log(LOG_ERR, "%s: unable to allocate from flowq_cache\n", __func__);
return NULL;
}
bzero(fq, flowq_size);
fq->fq_ptype = ptype;
if (ptype == QP_MBUF) {
MBUFQ_INIT(&fq->fq_mbufq);
}
CLASSQ_PKT_INIT(&fq->fq_dq_head);
CLASSQ_PKT_INIT(&fq->fq_dq_tail);
fq->fq_in_dqlist = false;
return fq;
}
void
fq_destroy(fq_t *fq)
{
VERIFY(fq->fq_flags & FQF_DESTROYED);
VERIFY(fq_empty(fq));
VERIFY(!(fq->fq_flags & (FQF_NEW_FLOW | FQF_OLD_FLOW)));
VERIFY(fq->fq_bytes == 0);
mcache_free(flowq_cache, fq);
}
static inline void
fq_detect_dequeue_stall(fq_if_t *fqs, fq_t *flowq, fq_if_classq_t *fq_cl,
u_int64_t *now)
{
u_int64_t maxgetqtime;
if (FQ_IS_DELAYHIGH(flowq) || flowq->fq_getqtime == 0 ||
fq_empty(flowq) ||
flowq->fq_bytes < FQ_MIN_FC_THRESHOLD_BYTES) {
return;
}
maxgetqtime = flowq->fq_getqtime + fqs->fqs_update_interval;
if ((*now) > maxgetqtime) {
/*
* there was no dequeue in an update interval worth of
* time. It means that the queue is stalled.
*/
FQ_SET_DELAY_HIGH(flowq);
fq_cl->fcl_stat.fcl_dequeue_stall++;
os_log_error(OS_LOG_DEFAULT, "%s: dequeue stall num: %d, "
"scidx: %d, flow: 0x%x, iface: %s", __func__,
fq_cl->fcl_stat.fcl_dequeue_stall, flowq->fq_sc_index,
flowq->fq_flowhash, if_name(fqs->fqs_ifq->ifcq_ifp));
}
}
void
fq_head_drop(fq_if_t *fqs, fq_t *fq)
{
pktsched_pkt_t pkt;
volatile uint32_t *pkt_flags;
uint64_t *pkt_timestamp;
struct ifclassq *ifq = fqs->fqs_ifq;
_PKTSCHED_PKT_INIT(&pkt);
fq_getq_flow_internal(fqs, fq, &pkt);
if (pkt.pktsched_pkt_mbuf == NULL) {
return;
}
pktsched_get_pkt_vars(&pkt, &pkt_flags, &pkt_timestamp, NULL, NULL,
NULL, NULL);
*pkt_timestamp = 0;
switch (pkt.pktsched_ptype) {
case QP_MBUF:
*pkt_flags &= ~PKTF_PRIV_GUARDED;
break;
default:
VERIFY(0);
/* NOTREACHED */
__builtin_unreachable();
}
IFCQ_DROP_ADD(ifq, 1, pktsched_get_pkt_len(&pkt));
IFCQ_CONVERT_LOCK(ifq);
pktsched_free_pkt(&pkt);
}
static int
fq_compressor(fq_if_t *fqs, fq_t *fq, fq_if_classq_t *fq_cl,
pktsched_pkt_t *pkt)
{
classq_pkt_type_t ptype = fq->fq_ptype;
uint32_t comp_gencnt = 0;
uint64_t *pkt_timestamp;
uint64_t old_timestamp = 0;
uint32_t old_pktlen = 0;
struct ifclassq *ifq = fqs->fqs_ifq;
if (__improbable(!tcp_do_ack_compression)) {
return 0;
}
pktsched_get_pkt_vars(pkt, NULL, &pkt_timestamp, NULL, NULL, NULL,
&comp_gencnt);
if (comp_gencnt == 0) {
return 0;
}
fq_cl->fcl_stat.fcl_pkts_compressible++;
if (fq_empty(fq)) {
return 0;
}
if (ptype == QP_MBUF) {
struct mbuf *m = MBUFQ_LAST(&fq->fq_mbufq);
if (comp_gencnt != m->m_pkthdr.comp_gencnt) {
return 0;
}
/* If we got until here, we should merge/replace the segment */
MBUFQ_REMOVE(&fq->fq_mbufq, m);
old_pktlen = m_pktlen(m);
old_timestamp = m->m_pkthdr.pkt_timestamp;
IFCQ_CONVERT_LOCK(fqs->fqs_ifq);
m_freem(m);
}
fq->fq_bytes -= old_pktlen;
fq_cl->fcl_stat.fcl_byte_cnt -= old_pktlen;
fq_cl->fcl_stat.fcl_pkt_cnt--;
IFCQ_DEC_LEN(ifq);
IFCQ_DEC_BYTES(ifq, old_pktlen);
*pkt_timestamp = old_timestamp;
return CLASSQEQ_COMPRESSED;
}
int
fq_addq(fq_if_t *fqs, pktsched_pkt_t *pkt, fq_if_classq_t *fq_cl)
{
int droptype = DTYPE_NODROP, fc_adv = 0, ret = CLASSQEQ_SUCCESS;
u_int64_t now;
fq_t *fq = NULL;
uint64_t *pkt_timestamp;
volatile uint32_t *pkt_flags;
uint32_t pkt_flowid, cnt;
uint8_t pkt_proto, pkt_flowsrc;
cnt = pkt->pktsched_pcnt;
pktsched_get_pkt_vars(pkt, &pkt_flags, &pkt_timestamp, &pkt_flowid,
&pkt_flowsrc, &pkt_proto, NULL);
/*
* XXX Not walking the chain to set this flag on every packet.
* This flag is only used for debugging. Nothing is affected if it's
* not set.
*/
switch (pkt->pktsched_ptype) {
case QP_MBUF:
/* See comments in <rdar://problem/14040693> */
VERIFY(!(*pkt_flags & PKTF_PRIV_GUARDED));
*pkt_flags |= PKTF_PRIV_GUARDED;
break;
default:
VERIFY(0);
/* NOTREACHED */
__builtin_unreachable();
}
/*
* Timestamps for every packet must be set prior to entering this path.
*/
now = *pkt_timestamp;
ASSERT(now > 0);
/* find the flowq for this packet */
fq = fq_if_hash_pkt(fqs, pkt_flowid, pktsched_get_pkt_svc(pkt),
now, TRUE, pkt->pktsched_ptype);
if (__improbable(fq == NULL)) {
DTRACE_IP1(memfail__drop, fq_if_t *, fqs);
/* drop the packet if we could not allocate a flow queue */
fq_cl->fcl_stat.fcl_drop_memfailure += cnt;
return CLASSQEQ_DROP;
}
VERIFY(fq->fq_ptype == pkt->pktsched_ptype);
fq_detect_dequeue_stall(fqs, fq, fq_cl, &now);
if (__improbable(FQ_IS_DELAYHIGH(fq))) {
if ((fq->fq_flags & FQF_FLOWCTL_CAPABLE) &&
(*pkt_flags & PKTF_FLOW_ADV)) {
fc_adv = 1;
/*
* If the flow is suspended or it is not
* TCP/QUIC, drop the chain.
*/
if ((pkt_proto != IPPROTO_TCP) &&
(pkt_proto != IPPROTO_QUIC)) {
droptype = DTYPE_EARLY;
fq_cl->fcl_stat.fcl_drop_early += cnt;
}
DTRACE_IP6(flow__adv, fq_if_t *, fqs,
fq_if_classq_t *, fq_cl, fq_t *, fq,
int, droptype, pktsched_pkt_t *, pkt,
uint32_t, cnt);
} else {
/*
* Need to drop packets to make room for the new
* ones. Try to drop from the head of the queue
* instead of the latest packets.
*/
if (!fq_empty(fq)) {
uint32_t i;
for (i = 0; i < cnt; i++) {
fq_head_drop(fqs, fq);
}
droptype = DTYPE_NODROP;
} else {
droptype = DTYPE_EARLY;
}
fq_cl->fcl_stat.fcl_drop_early += cnt;
DTRACE_IP6(no__flow__adv, fq_if_t *, fqs,
fq_if_classq_t *, fq_cl, fq_t *, fq,
int, droptype, pktsched_pkt_t *, pkt,
uint32_t, cnt);
}
}
/* Set the return code correctly */
if (__improbable(fc_adv == 1 && droptype != DTYPE_FORCED)) {
if (fq_if_add_fcentry(fqs, pkt, pkt_flowsrc, fq, fq_cl)) {
fq->fq_flags |= FQF_FLOWCTL_ON;
/* deliver flow control advisory error */
if (droptype == DTYPE_NODROP) {
ret = CLASSQEQ_SUCCESS_FC;
} else {
/* dropped due to flow control */
ret = CLASSQEQ_DROP_FC;
}
} else {
/*
* if we could not flow control the flow, it is
* better to drop
*/
droptype = DTYPE_FORCED;
ret = CLASSQEQ_DROP_FC;
fq_cl->fcl_stat.fcl_flow_control_fail++;
}
DTRACE_IP3(fc__ret, fq_if_t *, fqs, int, droptype, int, ret);
}
/*
* If the queue length hits the queue limit, drop a chain with the
* same number of packets from the front of the queue for a flow with
* maximum number of bytes. This will penalize heavy and unresponsive
* flows. It will also avoid a tail drop.
*/
if (__improbable(droptype == DTYPE_NODROP &&
fq_if_at_drop_limit(fqs))) {
uint32_t i;
if (fqs->fqs_large_flow == fq) {
/*
* Drop from the head of the current fq. Since a
* new packet will be added to the tail, it is ok
* to leave fq in place.
*/
DTRACE_IP5(large__flow, fq_if_t *, fqs,
fq_if_classq_t *, fq_cl, fq_t *, fq,
pktsched_pkt_t *, pkt, uint32_t, cnt);
for (i = 0; i < cnt; i++) {
fq_head_drop(fqs, fq);
}
} else {
if (fqs->fqs_large_flow == NULL) {
droptype = DTYPE_FORCED;
fq_cl->fcl_stat.fcl_drop_overflow += cnt;
ret = CLASSQEQ_DROP;
DTRACE_IP5(no__large__flow, fq_if_t *, fqs,
fq_if_classq_t *, fq_cl, fq_t *, fq,
pktsched_pkt_t *, pkt, uint32_t, cnt);
/*
* if this fq was freshly created and there
* is nothing to enqueue, free it
*/
if (fq_empty(fq) && !(fq->fq_flags &
(FQF_NEW_FLOW | FQF_OLD_FLOW))) {
fq_if_destroy_flow(fqs, fq_cl, fq, true);
fq = NULL;
}
} else {
DTRACE_IP5(different__large__flow,
fq_if_t *, fqs, fq_if_classq_t *, fq_cl,
fq_t *, fq, pktsched_pkt_t *, pkt,
uint32_t, cnt);
for (i = 0; i < cnt; i++) {
fq_if_drop_packet(fqs);
}
}
}
}
if (__probable(droptype == DTYPE_NODROP)) {
uint32_t chain_len = pktsched_get_pkt_len(pkt);
/*
* We do not compress if we are enqueuing a chain.
* Traversing the chain to look for acks would defeat the
* purpose of batch enqueueing.
*/
if (cnt == 1) {
ret = fq_compressor(fqs, fq, fq_cl, pkt);
if (ret != CLASSQEQ_COMPRESSED) {
ret = CLASSQEQ_SUCCESS;
} else {
fq_cl->fcl_stat.fcl_pkts_compressed++;
}
}
DTRACE_IP5(fq_enqueue, fq_if_t *, fqs, fq_if_classq_t *, fq_cl,
fq_t *, fq, pktsched_pkt_t *, pkt, uint32_t, cnt);
fq_enqueue(fq, pkt->pktsched_pkt, pkt->pktsched_tail, cnt);
fq->fq_bytes += chain_len;
fq_cl->fcl_stat.fcl_byte_cnt += chain_len;
fq_cl->fcl_stat.fcl_pkt_cnt += cnt;
/*
* check if this queue will qualify to be the next
* victim queue
*/
fq_if_is_flow_heavy(fqs, fq);
} else {
DTRACE_IP3(fq_drop, fq_if_t *, fqs, int, droptype, int, ret);
return (ret != CLASSQEQ_SUCCESS) ? ret : CLASSQEQ_DROP;
}
/*
* If the queue is not currently active, add it to the end of new
* flows list for that service class.
*/
if ((fq->fq_flags & (FQF_NEW_FLOW | FQF_OLD_FLOW)) == 0) {
VERIFY(STAILQ_NEXT(fq, fq_actlink) == NULL);
STAILQ_INSERT_TAIL(&fq_cl->fcl_new_flows, fq, fq_actlink);
fq->fq_flags |= FQF_NEW_FLOW;
fq_cl->fcl_stat.fcl_newflows_cnt++;
fq->fq_deficit = fq_cl->fcl_quantum;
}
return ret;
}
void
fq_getq_flow_internal(fq_if_t *fqs, fq_t *fq, pktsched_pkt_t *pkt)
{
classq_pkt_t p = CLASSQ_PKT_INITIALIZER(p);
uint32_t plen;
fq_if_classq_t *fq_cl;
struct ifclassq *ifq = fqs->fqs_ifq;
fq_dequeue(fq, &p);
if (p.cp_ptype == QP_INVALID) {
VERIFY(p.cp_mbuf == NULL);
return;
}
pktsched_pkt_encap(pkt, &p);
plen = pktsched_get_pkt_len(pkt);
VERIFY(fq->fq_bytes >= plen);
fq->fq_bytes -= plen;
fq_cl = &fqs->fqs_classq[fq->fq_sc_index];
fq_cl->fcl_stat.fcl_byte_cnt -= plen;
fq_cl->fcl_stat.fcl_pkt_cnt--;
IFCQ_DEC_LEN(ifq);
IFCQ_DEC_BYTES(ifq, plen);
/* Reset getqtime so that we don't count idle times */
if (fq_empty(fq)) {
fq->fq_getqtime = 0;
}
}
void
fq_getq_flow(fq_if_t *fqs, fq_t *fq, pktsched_pkt_t *pkt)
{
fq_if_classq_t *fq_cl;
u_int64_t now;
int64_t qdelay = 0;
struct timespec now_ts;
volatile uint32_t *pkt_flags;
uint64_t *pkt_timestamp;
fq_getq_flow_internal(fqs, fq, pkt);
if (pkt->pktsched_ptype == QP_INVALID) {
VERIFY(pkt->pktsched_pkt_mbuf == NULL);
return;
}
pktsched_get_pkt_vars(pkt, &pkt_flags, &pkt_timestamp, NULL, NULL,
NULL, NULL);
nanouptime(&now_ts);
now = (now_ts.tv_sec * NSEC_PER_SEC) + now_ts.tv_nsec;
/* this will compute qdelay in nanoseconds */
if (now > *pkt_timestamp) {
qdelay = now - *pkt_timestamp;
}
fq_cl = &fqs->fqs_classq[fq->fq_sc_index];
if (fq->fq_min_qdelay == 0 ||
(qdelay > 0 && (u_int64_t)qdelay < fq->fq_min_qdelay)) {
fq->fq_min_qdelay = qdelay;
}
if (now >= fq->fq_updatetime) {
if (fq->fq_min_qdelay > fqs->fqs_target_qdelay) {
if (!FQ_IS_DELAYHIGH(fq)) {
FQ_SET_DELAY_HIGH(fq);
os_log_error(OS_LOG_DEFAULT,
"%s: high delay idx: %d, %llu, flow: 0x%x, "
"iface: %s", __func__, fq->fq_sc_index,
fq->fq_min_qdelay, fq->fq_flowhash,
if_name(fqs->fqs_ifq->ifcq_ifp));
}
} else {
FQ_CLEAR_DELAY_HIGH(fq);
}
/* Reset measured queue delay and update time */
fq->fq_updatetime = now + fqs->fqs_update_interval;
fq->fq_min_qdelay = 0;
}
if (!FQ_IS_DELAYHIGH(fq) || fq_empty(fq)) {
FQ_CLEAR_DELAY_HIGH(fq);
if (fq->fq_flags & FQF_FLOWCTL_ON) {
fq_if_flow_feedback(fqs, fq, fq_cl);
}
}
if (fq_empty(fq)) {
/* Reset getqtime so that we don't count idle times */
fq->fq_getqtime = 0;
} else {
fq->fq_getqtime = now;
}
fq_if_is_flow_heavy(fqs, fq);
*pkt_timestamp = 0;
switch (pkt->pktsched_ptype) {
case QP_MBUF:
*pkt_flags &= ~PKTF_PRIV_GUARDED;
break;
default:
VERIFY(0);
/* NOTREACHED */
__builtin_unreachable();
}
}