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freebsd-skq/sys/netinet/tcp_hpts.c
glebius b1b7d9cff8 In TCP HPTS enter the epoch in tcp_hpts_thread() and assert it in 
the leaf functions.
2019-11-07 21:30:27 +00:00

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/*-
* Copyright (c) 2016-2018 Netflix, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_inet.h"
#include "opt_inet6.h"
#include "opt_tcpdebug.h"
/**
* Some notes about usage.
*
* The tcp_hpts system is designed to provide a high precision timer
* system for tcp. Its main purpose is to provide a mechanism for
* pacing packets out onto the wire. It can be used in two ways
* by a given TCP stack (and those two methods can be used simultaneously).
*
* First, and probably the main thing its used by Rack and BBR, it can
* be used to call tcp_output() of a transport stack at some time in the future.
* The normal way this is done is that tcp_output() of the stack schedules
* itself to be called again by calling tcp_hpts_insert(tcpcb, slot). The
* slot is the time from now that the stack wants to be called but it
* must be converted to tcp_hpts's notion of slot. This is done with
* one of the macros HPTS_MS_TO_SLOTS or HPTS_USEC_TO_SLOTS. So a typical
* call from the tcp_output() routine might look like:
*
* tcp_hpts_insert(tp, HPTS_USEC_TO_SLOTS(550));
*
* The above would schedule tcp_ouput() to be called in 550 useconds.
* Note that if using this mechanism the stack will want to add near
* its top a check to prevent unwanted calls (from user land or the
* arrival of incoming ack's). So it would add something like:
*
* if (inp->inp_in_hpts)
* return;
*
* to prevent output processing until the time alotted has gone by.
* Of course this is a bare bones example and the stack will probably
* have more consideration then just the above.
*
* Now the second function (actually two functions I guess :D)
* the tcp_hpts system provides is the ability to either abort
* a connection (later) or process input on a connection.
* Why would you want to do this? To keep processor locality
* and or not have to worry about untangling any recursive
* locks. The input function now is hooked to the new LRO
* system as well.
*
* In order to use the input redirection function the
* tcp stack must define an input function for
* tfb_do_queued_segments(). This function understands
* how to dequeue a array of packets that were input and
* knows how to call the correct processing routine.
*
* Locking in this is important as well so most likely the
* stack will need to define the tfb_do_segment_nounlock()
* splitting tfb_do_segment() into two parts. The main processing
* part that does not unlock the INP and returns a value of 1 or 0.
* It returns 0 if all is well and the lock was not released. It
* returns 1 if we had to destroy the TCB (a reset received etc).
* The remains of tfb_do_segment() then become just a simple call
* to the tfb_do_segment_nounlock() function and check the return
* code and possibly unlock.
*
* The stack must also set the flag on the INP that it supports this
* feature i.e. INP_SUPPORTS_MBUFQ. The LRO code recoginizes
* this flag as well and will queue packets when it is set.
* There are other flags as well INP_MBUF_QUEUE_READY and
* INP_DONT_SACK_QUEUE. The first flag tells the LRO code
* that we are in the pacer for output so there is no
* need to wake up the hpts system to get immediate
* input. The second tells the LRO code that its okay
* if a SACK arrives you can still defer input and let
* the current hpts timer run (this is usually set when
* a rack timer is up so we know SACK's are happening
* on the connection already and don't want to wakeup yet).
*
* There is a common functions within the rack_bbr_common code
* version i.e. ctf_do_queued_segments(). This function
* knows how to take the input queue of packets from
* tp->t_in_pkts and process them digging out
* all the arguments, calling any bpf tap and
* calling into tfb_do_segment_nounlock(). The common
* function (ctf_do_queued_segments()) requires that
* you have defined the tfb_do_segment_nounlock() as
* described above.
*
* The second feature of the input side of hpts is the
* dropping of a connection. This is due to the way that
* locking may have occured on the INP_WLOCK. So if
* a stack wants to drop a connection it calls:
*
* tcp_set_inp_to_drop(tp, ETIMEDOUT)
*
* To schedule the tcp_hpts system to call
*
* tcp_drop(tp, drop_reason)
*
* at a future point. This is quite handy to prevent locking
* issues when dropping connections.
*
*/
#include <sys/param.h>
#include <sys/bus.h>
#include <sys/interrupt.h>
#include <sys/module.h>
#include <sys/kernel.h>
#include <sys/hhook.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/proc.h> /* for proc0 declaration */
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/sysctl.h>
#include <sys/systm.h>
#include <sys/refcount.h>
#include <sys/sched.h>
#include <sys/queue.h>
#include <sys/smp.h>
#include <sys/counter.h>
#include <sys/time.h>
#include <sys/kthread.h>
#include <sys/kern_prefetch.h>
#include <vm/uma.h>
#include <vm/vm.h>
#include <net/route.h>
#include <net/vnet.h>
#define TCPSTATES /* for logging */
#include <netinet/in.h>
#include <netinet/in_kdtrace.h>
#include <netinet/in_pcb.h>
#include <netinet/ip.h>
#include <netinet/ip_icmp.h> /* required for icmp_var.h */
#include <netinet/icmp_var.h> /* for ICMP_BANDLIM */
#include <netinet/ip_var.h>
#include <netinet/ip6.h>
#include <netinet6/in6_pcb.h>
#include <netinet6/ip6_var.h>
#include <netinet/tcp.h>
#include <netinet/tcp_fsm.h>
#include <netinet/tcp_seq.h>
#include <netinet/tcp_timer.h>
#include <netinet/tcp_var.h>
#include <netinet/tcpip.h>
#include <netinet/cc/cc.h>
#include <netinet/tcp_hpts.h>
#include <netinet/tcp_log_buf.h>
#ifdef tcpdebug
#include <netinet/tcp_debug.h>
#endif /* tcpdebug */
#ifdef tcp_offload
#include <netinet/tcp_offload.h>
#endif
#include "opt_rss.h"
MALLOC_DEFINE(M_TCPHPTS, "tcp_hpts", "TCP hpts");
#ifdef RSS
static int tcp_bind_threads = 1;
#else
static int tcp_bind_threads = 2;
#endif
TUNABLE_INT("net.inet.tcp.bind_hptss", &tcp_bind_threads);
static struct tcp_hptsi tcp_pace;
static int hpts_does_tp_logging = 0;
static void tcp_wakehpts(struct tcp_hpts_entry *p);
static void tcp_wakeinput(struct tcp_hpts_entry *p);
static void tcp_input_data(struct tcp_hpts_entry *hpts, struct timeval *tv);
static void tcp_hptsi(struct tcp_hpts_entry *hpts);
static void tcp_hpts_thread(void *ctx);
static void tcp_init_hptsi(void *st);
int32_t tcp_min_hptsi_time = DEFAULT_MIN_SLEEP;
static int32_t tcp_hpts_callout_skip_swi = 0;
SYSCTL_NODE(_net_inet_tcp, OID_AUTO, hpts, CTLFLAG_RW, 0, "TCP Hpts controls");
#define timersub(tvp, uvp, vvp) \
do { \
(vvp)->tv_sec = (tvp)->tv_sec - (uvp)->tv_sec; \
(vvp)->tv_usec = (tvp)->tv_usec - (uvp)->tv_usec; \
if ((vvp)->tv_usec < 0) { \
(vvp)->tv_sec--; \
(vvp)->tv_usec += 1000000; \
} \
} while (0)
static int32_t tcp_hpts_precision = 120;
struct hpts_domain_info {
int count;
int cpu[MAXCPU];
};
struct hpts_domain_info hpts_domains[MAXMEMDOM];
SYSCTL_INT(_net_inet_tcp_hpts, OID_AUTO, precision, CTLFLAG_RW,
&tcp_hpts_precision, 120,
"Value for PRE() precision of callout");
counter_u64_t hpts_hopelessly_behind;
SYSCTL_COUNTER_U64(_net_inet_tcp_hpts, OID_AUTO, hopeless, CTLFLAG_RD,
&hpts_hopelessly_behind,
"Number of times hpts could not catch up and was behind hopelessly");
counter_u64_t hpts_loops;
SYSCTL_COUNTER_U64(_net_inet_tcp_hpts, OID_AUTO, loops, CTLFLAG_RD,
&hpts_loops, "Number of times hpts had to loop to catch up");
counter_u64_t back_tosleep;
SYSCTL_COUNTER_U64(_net_inet_tcp_hpts, OID_AUTO, no_tcbsfound, CTLFLAG_RD,
&back_tosleep, "Number of times hpts found no tcbs");
counter_u64_t combined_wheel_wrap;
SYSCTL_COUNTER_U64(_net_inet_tcp_hpts, OID_AUTO, comb_wheel_wrap, CTLFLAG_RD,
&combined_wheel_wrap, "Number of times the wheel lagged enough to have an insert see wrap");
counter_u64_t wheel_wrap;
SYSCTL_COUNTER_U64(_net_inet_tcp_hpts, OID_AUTO, wheel_wrap, CTLFLAG_RD,
&wheel_wrap, "Number of times the wheel lagged enough to have an insert see wrap");
static int32_t out_ts_percision = 0;
SYSCTL_INT(_net_inet_tcp_hpts, OID_AUTO, out_tspercision, CTLFLAG_RW,
&out_ts_percision, 0,
"Do we use a percise timestamp for every output cts");
SYSCTL_INT(_net_inet_tcp_hpts, OID_AUTO, logging, CTLFLAG_RW,
&hpts_does_tp_logging, 0,
"Do we add to any tp that has logging on pacer logs");
static int32_t max_pacer_loops = 10;
SYSCTL_INT(_net_inet_tcp_hpts, OID_AUTO, loopmax, CTLFLAG_RW,
&max_pacer_loops, 10,
"What is the maximum number of times the pacer will loop trying to catch up");
#define HPTS_MAX_SLEEP_ALLOWED (NUM_OF_HPTSI_SLOTS/2)
static uint32_t hpts_sleep_max = HPTS_MAX_SLEEP_ALLOWED;
static int
sysctl_net_inet_tcp_hpts_max_sleep(SYSCTL_HANDLER_ARGS)
{
int error;
uint32_t new;
new = hpts_sleep_max;
error = sysctl_handle_int(oidp, &new, 0, req);
if (error == 0 && req->newptr) {
if ((new < (NUM_OF_HPTSI_SLOTS / 4)) ||
(new > HPTS_MAX_SLEEP_ALLOWED))
error = EINVAL;
else
hpts_sleep_max = new;
}
return (error);
}
SYSCTL_PROC(_net_inet_tcp_hpts, OID_AUTO, maxsleep,
CTLTYPE_UINT | CTLFLAG_RW,
&hpts_sleep_max, 0,
&sysctl_net_inet_tcp_hpts_max_sleep, "IU",
"Maximum time hpts will sleep");
SYSCTL_INT(_net_inet_tcp_hpts, OID_AUTO, minsleep, CTLFLAG_RW,
&tcp_min_hptsi_time, 0,
"The minimum time the hpts must sleep before processing more slots");
SYSCTL_INT(_net_inet_tcp_hpts, OID_AUTO, skip_swi, CTLFLAG_RW,
&tcp_hpts_callout_skip_swi, 0,
"Do we have the callout call directly to the hpts?");
static void
tcp_hpts_log(struct tcp_hpts_entry *hpts, struct tcpcb *tp, struct timeval *tv,
int ticks_to_run, int idx)
{
union tcp_log_stackspecific log;
memset(&log.u_bbr, 0, sizeof(log.u_bbr));
log.u_bbr.flex1 = hpts->p_nxt_slot;
log.u_bbr.flex2 = hpts->p_cur_slot;
log.u_bbr.flex3 = hpts->p_prev_slot;
log.u_bbr.flex4 = idx;
log.u_bbr.flex5 = hpts->p_curtick;
log.u_bbr.flex6 = hpts->p_on_queue_cnt;
log.u_bbr.use_lt_bw = 1;
log.u_bbr.inflight = ticks_to_run;
log.u_bbr.applimited = hpts->overidden_sleep;
log.u_bbr.delivered = hpts->saved_curtick;
log.u_bbr.timeStamp = tcp_tv_to_usectick(tv);
log.u_bbr.epoch = hpts->saved_curslot;
log.u_bbr.lt_epoch = hpts->saved_prev_slot;
log.u_bbr.pkts_out = hpts->p_delayed_by;
log.u_bbr.lost = hpts->p_hpts_sleep_time;
log.u_bbr.cur_del_rate = hpts->p_runningtick;
TCP_LOG_EVENTP(tp, NULL,
&tp->t_inpcb->inp_socket->so_rcv,
&tp->t_inpcb->inp_socket->so_snd,
BBR_LOG_HPTSDIAG, 0,
0, &log, false, tv);
}
static void
hpts_timeout_swi(void *arg)
{
struct tcp_hpts_entry *hpts;
hpts = (struct tcp_hpts_entry *)arg;
swi_sched(hpts->ie_cookie, 0);
}
static void
hpts_timeout_dir(void *arg)
{
tcp_hpts_thread(arg);
}
static inline void
hpts_sane_pace_remove(struct tcp_hpts_entry *hpts, struct inpcb *inp, struct hptsh *head, int clear)
{
#ifdef INVARIANTS
if (mtx_owned(&hpts->p_mtx) == 0) {
/* We don't own the mutex? */
panic("%s: hpts:%p inp:%p no hpts mutex", __FUNCTION__, hpts, inp);
}
if (hpts->p_cpu != inp->inp_hpts_cpu) {
/* It is not the right cpu/mutex? */
panic("%s: hpts:%p inp:%p incorrect CPU", __FUNCTION__, hpts, inp);
}
if (inp->inp_in_hpts == 0) {
/* We are not on the hpts? */
panic("%s: hpts:%p inp:%p not on the hpts?", __FUNCTION__, hpts, inp);
}
#endif
TAILQ_REMOVE(head, inp, inp_hpts);
hpts->p_on_queue_cnt--;
if (hpts->p_on_queue_cnt < 0) {
/* Count should not go negative .. */
#ifdef INVARIANTS
panic("Hpts goes negative inp:%p hpts:%p",
inp, hpts);
#endif
hpts->p_on_queue_cnt = 0;
}
if (clear) {
inp->inp_hpts_request = 0;
inp->inp_in_hpts = 0;
}
}
static inline void
hpts_sane_pace_insert(struct tcp_hpts_entry *hpts, struct inpcb *inp, struct hptsh *head, int line, int noref)
{
#ifdef INVARIANTS
if (mtx_owned(&hpts->p_mtx) == 0) {
/* We don't own the mutex? */
panic("%s: hpts:%p inp:%p no hpts mutex", __FUNCTION__, hpts, inp);
}
if (hpts->p_cpu != inp->inp_hpts_cpu) {
/* It is not the right cpu/mutex? */
panic("%s: hpts:%p inp:%p incorrect CPU", __FUNCTION__, hpts, inp);
}
if ((noref == 0) && (inp->inp_in_hpts == 1)) {
/* We are already on the hpts? */
panic("%s: hpts:%p inp:%p already on the hpts?", __FUNCTION__, hpts, inp);
}
#endif
TAILQ_INSERT_TAIL(head, inp, inp_hpts);
inp->inp_in_hpts = 1;
hpts->p_on_queue_cnt++;
if (noref == 0) {
in_pcbref(inp);
}
}
static inline void
hpts_sane_input_remove(struct tcp_hpts_entry *hpts, struct inpcb *inp, int clear)
{
#ifdef INVARIANTS
if (mtx_owned(&hpts->p_mtx) == 0) {
/* We don't own the mutex? */
panic("%s: hpts:%p inp:%p no hpts mutex", __FUNCTION__, hpts, inp);
}
if (hpts->p_cpu != inp->inp_input_cpu) {
/* It is not the right cpu/mutex? */
panic("%s: hpts:%p inp:%p incorrect CPU", __FUNCTION__, hpts, inp);
}
if (inp->inp_in_input == 0) {
/* We are not on the input hpts? */
panic("%s: hpts:%p inp:%p not on the input hpts?", __FUNCTION__, hpts, inp);
}
#endif
TAILQ_REMOVE(&hpts->p_input, inp, inp_input);
hpts->p_on_inqueue_cnt--;
if (hpts->p_on_inqueue_cnt < 0) {
#ifdef INVARIANTS
panic("Hpts in goes negative inp:%p hpts:%p",
inp, hpts);
#endif
hpts->p_on_inqueue_cnt = 0;
}
#ifdef INVARIANTS
if (TAILQ_EMPTY(&hpts->p_input) &&
(hpts->p_on_inqueue_cnt != 0)) {
/* We should not be empty with a queue count */
panic("%s hpts:%p in_hpts input empty but cnt:%d",
__FUNCTION__, hpts, hpts->p_on_inqueue_cnt);
}
#endif
if (clear)
inp->inp_in_input = 0;
}
static inline void
hpts_sane_input_insert(struct tcp_hpts_entry *hpts, struct inpcb *inp, int line)
{
#ifdef INVARIANTS
if (mtx_owned(&hpts->p_mtx) == 0) {
/* We don't own the mutex? */
panic("%s: hpts:%p inp:%p no hpts mutex", __FUNCTION__, hpts, inp);
}
if (hpts->p_cpu != inp->inp_input_cpu) {
/* It is not the right cpu/mutex? */
panic("%s: hpts:%p inp:%p incorrect CPU", __FUNCTION__, hpts, inp);
}
if (inp->inp_in_input == 1) {
/* We are already on the input hpts? */
panic("%s: hpts:%p inp:%p already on the input hpts?", __FUNCTION__, hpts, inp);
}
#endif
TAILQ_INSERT_TAIL(&hpts->p_input, inp, inp_input);
inp->inp_in_input = 1;
hpts->p_on_inqueue_cnt++;
in_pcbref(inp);
}
static void
tcp_wakehpts(struct tcp_hpts_entry *hpts)
{
HPTS_MTX_ASSERT(hpts);
if (hpts->p_hpts_wake_scheduled == 0) {
hpts->p_hpts_wake_scheduled = 1;
swi_sched(hpts->ie_cookie, 0);
}
}
static void
tcp_wakeinput(struct tcp_hpts_entry *hpts)
{
HPTS_MTX_ASSERT(hpts);
if (hpts->p_hpts_wake_scheduled == 0) {
hpts->p_hpts_wake_scheduled = 1;
swi_sched(hpts->ie_cookie, 0);
}
}
struct tcp_hpts_entry *
tcp_cur_hpts(struct inpcb *inp)
{
int32_t hpts_num;
struct tcp_hpts_entry *hpts;
hpts_num = inp->inp_hpts_cpu;
hpts = tcp_pace.rp_ent[hpts_num];
return (hpts);
}
struct tcp_hpts_entry *
tcp_hpts_lock(struct inpcb *inp)
{
struct tcp_hpts_entry *hpts;
int32_t hpts_num;
again:
hpts_num = inp->inp_hpts_cpu;
hpts = tcp_pace.rp_ent[hpts_num];
#ifdef INVARIANTS
if (mtx_owned(&hpts->p_mtx)) {
panic("Hpts:%p owns mtx prior-to lock line:%d",
hpts, __LINE__);
}
#endif
mtx_lock(&hpts->p_mtx);
if (hpts_num != inp->inp_hpts_cpu) {
mtx_unlock(&hpts->p_mtx);
goto again;
}
return (hpts);
}
struct tcp_hpts_entry *
tcp_input_lock(struct inpcb *inp)
{
struct tcp_hpts_entry *hpts;
int32_t hpts_num;
again:
hpts_num = inp->inp_input_cpu;
hpts = tcp_pace.rp_ent[hpts_num];
#ifdef INVARIANTS
if (mtx_owned(&hpts->p_mtx)) {
panic("Hpts:%p owns mtx prior-to lock line:%d",
hpts, __LINE__);
}
#endif
mtx_lock(&hpts->p_mtx);
if (hpts_num != inp->inp_input_cpu) {
mtx_unlock(&hpts->p_mtx);
goto again;
}
return (hpts);
}
static void
tcp_remove_hpts_ref(struct inpcb *inp, struct tcp_hpts_entry *hpts, int line)
{
int32_t add_freed;
if (inp->inp_flags2 & INP_FREED) {
/*
* Need to play a special trick so that in_pcbrele_wlocked
* does not return 1 when it really should have returned 0.
*/
add_freed = 1;
inp->inp_flags2 &= ~INP_FREED;
} else {
add_freed = 0;
}
#ifndef INP_REF_DEBUG
if (in_pcbrele_wlocked(inp)) {
/*
* This should not happen. We have the inpcb referred to by
* the main socket (why we are called) and the hpts. It
* should always return 0.
*/
panic("inpcb:%p release ret 1",
inp);
}
#else
if (__in_pcbrele_wlocked(inp, line)) {
/*
* This should not happen. We have the inpcb referred to by
* the main socket (why we are called) and the hpts. It
* should always return 0.
*/
panic("inpcb:%p release ret 1",
inp);
}
#endif
if (add_freed) {
inp->inp_flags2 |= INP_FREED;
}
}
static void
tcp_hpts_remove_locked_output(struct tcp_hpts_entry *hpts, struct inpcb *inp, int32_t flags, int32_t line)
{
if (inp->inp_in_hpts) {
hpts_sane_pace_remove(hpts, inp, &hpts->p_hptss[inp->inp_hptsslot], 1);
tcp_remove_hpts_ref(inp, hpts, line);
}
}
static void
tcp_hpts_remove_locked_input(struct tcp_hpts_entry *hpts, struct inpcb *inp, int32_t flags, int32_t line)
{
HPTS_MTX_ASSERT(hpts);
if (inp->inp_in_input) {
hpts_sane_input_remove(hpts, inp, 1);
tcp_remove_hpts_ref(inp, hpts, line);
}
}
/*
* Called normally with the INP_LOCKED but it
* does not matter, the hpts lock is the key
* but the lock order allows us to hold the
* INP lock and then get the hpts lock.
*
* Valid values in the flags are
* HPTS_REMOVE_OUTPUT - remove from the output of the hpts.
* HPTS_REMOVE_INPUT - remove from the input of the hpts.
* Note that you can use one or both values together
* and get two actions.
*/
void
__tcp_hpts_remove(struct inpcb *inp, int32_t flags, int32_t line)
{
struct tcp_hpts_entry *hpts;
INP_WLOCK_ASSERT(inp);
if (flags & HPTS_REMOVE_OUTPUT) {
hpts = tcp_hpts_lock(inp);
tcp_hpts_remove_locked_output(hpts, inp, flags, line);
mtx_unlock(&hpts->p_mtx);
}
if (flags & HPTS_REMOVE_INPUT) {
hpts = tcp_input_lock(inp);
tcp_hpts_remove_locked_input(hpts, inp, flags, line);
mtx_unlock(&hpts->p_mtx);
}
}
static inline int
hpts_tick(uint32_t wheel_tick, uint32_t plus)
{
/*
* Given a slot on the wheel, what slot
* is that plus ticks out?
*/
KASSERT(wheel_tick < NUM_OF_HPTSI_SLOTS, ("Invalid tick %u not on wheel", wheel_tick));
return ((wheel_tick + plus) % NUM_OF_HPTSI_SLOTS);
}
static inline int
tick_to_wheel(uint32_t cts_in_wticks)
{
/*
* Given a timestamp in wheel ticks (10usec inc's)
* map it to our limited space wheel.
*/
return (cts_in_wticks % NUM_OF_HPTSI_SLOTS);
}
static inline int
hpts_ticks_diff(int prev_tick, int tick_now)
{
/*
* Given two ticks that are someplace
* on our wheel. How far are they apart?
*/
if (tick_now > prev_tick)
return (tick_now - prev_tick);
else if (tick_now == prev_tick)
/*
* Special case, same means we can go all of our
* wheel less one slot.
*/
return (NUM_OF_HPTSI_SLOTS - 1);
else
return ((NUM_OF_HPTSI_SLOTS - prev_tick) + tick_now);
}
/*
* Given a tick on the wheel that is the current time
* mapped to the wheel (wheel_tick), what is the maximum
* distance forward that can be obtained without
* wrapping past either prev_tick or running_tick
* depending on the htps state? Also if passed
* a uint32_t *, fill it with the tick location.
*
* Note if you do not give this function the current
* time (that you think it is) mapped to the wheel
* then the results will not be what you expect and
* could lead to invalid inserts.
*/
static inline int32_t
max_ticks_available(struct tcp_hpts_entry *hpts, uint32_t wheel_tick, uint32_t *target_tick)
{
uint32_t dis_to_travel, end_tick, pacer_to_now, avail_on_wheel;
if ((hpts->p_hpts_active == 1) &&
(hpts->p_wheel_complete == 0)) {
end_tick = hpts->p_runningtick;
/* Back up one tick */
if (end_tick == 0)
end_tick = NUM_OF_HPTSI_SLOTS - 1;
else
end_tick--;
if (target_tick)
*target_tick = end_tick;
} else {
/*
* For the case where we are
* not active, or we have
* completed the pass over
* the wheel, we can use the
* prev tick and subtract one from it. This puts us
* as far out as possible on the wheel.
*/
end_tick = hpts->p_prev_slot;
if (end_tick == 0)
end_tick = NUM_OF_HPTSI_SLOTS - 1;
else
end_tick--;
if (target_tick)
*target_tick = end_tick;
/*
* Now we have close to the full wheel left minus the
* time it has been since the pacer went to sleep. Note
* that wheel_tick, passed in, should be the current time
* from the perspective of the caller, mapped to the wheel.
*/
if (hpts->p_prev_slot != wheel_tick)
dis_to_travel = hpts_ticks_diff(hpts->p_prev_slot, wheel_tick);
else
dis_to_travel = 1;
/*
* dis_to_travel in this case is the space from when the
* pacer stopped (p_prev_slot) and where our wheel_tick
* is now. To know how many slots we can put it in we
* subtract from the wheel size. We would not want
* to place something after p_prev_slot or it will
* get ran too soon.
*/
return (NUM_OF_HPTSI_SLOTS - dis_to_travel);
}
/*
* So how many slots are open between p_runningtick -> p_cur_slot
* that is what is currently un-available for insertion. Special
* case when we are at the last slot, this gets 1, so that
* the answer to how many slots are available is all but 1.
*/
if (hpts->p_runningtick == hpts->p_cur_slot)
dis_to_travel = 1;
else
dis_to_travel = hpts_ticks_diff(hpts->p_runningtick, hpts->p_cur_slot);
/*
* How long has the pacer been running?
*/
if (hpts->p_cur_slot != wheel_tick) {
/* The pacer is a bit late */
pacer_to_now = hpts_ticks_diff(hpts->p_cur_slot, wheel_tick);
} else {
/* The pacer is right on time, now == pacers start time */
pacer_to_now = 0;
}
/*
* To get the number left we can insert into we simply
* subract the distance the pacer has to run from how
* many slots there are.
*/
avail_on_wheel = NUM_OF_HPTSI_SLOTS - dis_to_travel;
/*
* Now how many of those we will eat due to the pacer's
* time (p_cur_slot) of start being behind the
* real time (wheel_tick)?
*/
if (avail_on_wheel <= pacer_to_now) {
/*
* Wheel wrap, we can't fit on the wheel, that
* is unusual the system must be way overloaded!
* Insert into the assured tick, and return special
* "0".
*/
counter_u64_add(combined_wheel_wrap, 1);
*target_tick = hpts->p_nxt_slot;
return (0);
} else {
/*
* We know how many slots are open
* on the wheel (the reverse of what
* is left to run. Take away the time
* the pacer started to now (wheel_tick)
* and that tells you how many slots are
* open that can be inserted into that won't
* be touched by the pacer until later.
*/
return (avail_on_wheel - pacer_to_now);
}
}
static int
tcp_queue_to_hpts_immediate_locked(struct inpcb *inp, struct tcp_hpts_entry *hpts, int32_t line, int32_t noref)
{
uint32_t need_wake = 0;
HPTS_MTX_ASSERT(hpts);
if (inp->inp_in_hpts == 0) {
/* Ok we need to set it on the hpts in the current slot */
inp->inp_hpts_request = 0;
if ((hpts->p_hpts_active == 0) ||
(hpts->p_wheel_complete)) {
/*
* A sleeping hpts we want in next slot to run
* note that in this state p_prev_slot == p_cur_slot
*/
inp->inp_hptsslot = hpts_tick(hpts->p_prev_slot, 1);
if ((hpts->p_on_min_sleep == 0) && (hpts->p_hpts_active == 0))
need_wake = 1;
} else if ((void *)inp == hpts->p_inp) {
/*
* The hpts system is running and the caller
* was awoken by the hpts system.
* We can't allow you to go into the same slot we
* are in (we don't want a loop :-D).
*/
inp->inp_hptsslot = hpts->p_nxt_slot;
} else
inp->inp_hptsslot = hpts->p_runningtick;
hpts_sane_pace_insert(hpts, inp, &hpts->p_hptss[inp->inp_hptsslot], line, noref);
if (need_wake) {
/*
* Activate the hpts if it is sleeping and its
* timeout is not 1.
*/
hpts->p_direct_wake = 1;
tcp_wakehpts(hpts);
}
}
return (need_wake);
}
int
__tcp_queue_to_hpts_immediate(struct inpcb *inp, int32_t line)
{
int32_t ret;
struct tcp_hpts_entry *hpts;
INP_WLOCK_ASSERT(inp);
hpts = tcp_hpts_lock(inp);
ret = tcp_queue_to_hpts_immediate_locked(inp, hpts, line, 0);
mtx_unlock(&hpts->p_mtx);
return (ret);
}
#ifdef INVARIANTS
static void
check_if_slot_would_be_wrong(struct tcp_hpts_entry *hpts, struct inpcb *inp, uint32_t inp_hptsslot, int line)
{
/*
* Sanity checks for the pacer with invariants
* on insert.
*/
if (inp_hptsslot >= NUM_OF_HPTSI_SLOTS)
panic("hpts:%p inp:%p slot:%d > max",
hpts, inp, inp_hptsslot);
if ((hpts->p_hpts_active) &&
(hpts->p_wheel_complete == 0)) {
/*
* If the pacer is processing a arc
* of the wheel, we need to make
* sure we are not inserting within
* that arc.
*/
int distance, yet_to_run;
distance = hpts_ticks_diff(hpts->p_runningtick, inp_hptsslot);
if (hpts->p_runningtick != hpts->p_cur_slot)
yet_to_run = hpts_ticks_diff(hpts->p_runningtick, hpts->p_cur_slot);
else
yet_to_run = 0; /* processing last slot */
if (yet_to_run > distance) {
panic("hpts:%p inp:%p slot:%d distance:%d yet_to_run:%d rs:%d cs:%d",
hpts, inp, inp_hptsslot,
distance, yet_to_run,
hpts->p_runningtick, hpts->p_cur_slot);
}
}
}
#endif
static void
tcp_hpts_insert_locked(struct tcp_hpts_entry *hpts, struct inpcb *inp, uint32_t slot, int32_t line,
struct hpts_diag *diag, struct timeval *tv)
{
uint32_t need_new_to = 0;
uint32_t wheel_cts, last_tick;
int32_t wheel_tick, maxticks;
int8_t need_wakeup = 0;
HPTS_MTX_ASSERT(hpts);
if (diag) {
memset(diag, 0, sizeof(struct hpts_diag));
diag->p_hpts_active = hpts->p_hpts_active;
diag->p_prev_slot = hpts->p_prev_slot;
diag->p_runningtick = hpts->p_runningtick;
diag->p_nxt_slot = hpts->p_nxt_slot;
diag->p_cur_slot = hpts->p_cur_slot;
diag->p_curtick = hpts->p_curtick;
diag->p_lasttick = hpts->p_lasttick;
diag->slot_req = slot;
diag->p_on_min_sleep = hpts->p_on_min_sleep;
diag->hpts_sleep_time = hpts->p_hpts_sleep_time;
}
if (inp->inp_in_hpts == 0) {
if (slot == 0) {
/* Immediate */
tcp_queue_to_hpts_immediate_locked(inp, hpts, line, 0);
return;
}
/* Get the current time relative to the wheel */
wheel_cts = tcp_tv_to_hptstick(tv);
/* Map it onto the wheel */
wheel_tick = tick_to_wheel(wheel_cts);
/* Now what's the max we can place it at? */
maxticks = max_ticks_available(hpts, wheel_tick, &last_tick);
if (diag) {
diag->wheel_tick = wheel_tick;
diag->maxticks = maxticks;
diag->wheel_cts = wheel_cts;
}
if (maxticks == 0) {
/* The pacer is in a wheel wrap behind, yikes! */
if (slot > 1) {
/*
* Reduce by 1 to prevent a forever loop in
* case something else is wrong. Note this
* probably does not hurt because the pacer
* if its true is so far behind we will be
* > 1second late calling anyway.
*/
slot--;
}
inp->inp_hptsslot = last_tick;
inp->inp_hpts_request = slot;
} else if (maxticks >= slot) {
/* It all fits on the wheel */
inp->inp_hpts_request = 0;
inp->inp_hptsslot = hpts_tick(wheel_tick, slot);
} else {
/* It does not fit */
inp->inp_hpts_request = slot - maxticks;
inp->inp_hptsslot = last_tick;
}
if (diag) {
diag->slot_remaining = inp->inp_hpts_request;
diag->inp_hptsslot = inp->inp_hptsslot;
}
#ifdef INVARIANTS
check_if_slot_would_be_wrong(hpts, inp, inp->inp_hptsslot, line);
#endif
hpts_sane_pace_insert(hpts, inp, &hpts->p_hptss[inp->inp_hptsslot], line, 0);
if ((hpts->p_hpts_active == 0) &&
(inp->inp_hpts_request == 0) &&
(hpts->p_on_min_sleep == 0)) {
/*
* The hpts is sleeping and not on a minimum
* sleep time, we need to figure out where
* it will wake up at and if we need to reschedule
* its time-out.
*/
uint32_t have_slept, yet_to_sleep;
/* Now do we need to restart the hpts's timer? */
have_slept = hpts_ticks_diff(hpts->p_prev_slot, wheel_tick);
if (have_slept < hpts->p_hpts_sleep_time)
yet_to_sleep = hpts->p_hpts_sleep_time - have_slept;
else {
/* We are over-due */
yet_to_sleep = 0;
need_wakeup = 1;
}
if (diag) {
diag->have_slept = have_slept;
diag->yet_to_sleep = yet_to_sleep;
}
if (yet_to_sleep &&
(yet_to_sleep > slot)) {
/*
* We need to reschedule the hpts's time-out.
*/
hpts->p_hpts_sleep_time = slot;
need_new_to = slot * HPTS_TICKS_PER_USEC;
}
}
/*
* Now how far is the hpts sleeping to? if active is 1, its
* up and ticking we do nothing, otherwise we may need to
* reschedule its callout if need_new_to is set from above.
*/
if (need_wakeup) {
hpts->p_direct_wake = 1;
tcp_wakehpts(hpts);
if (diag) {
diag->need_new_to = 0;
diag->co_ret = 0xffff0000;
}
} else if (need_new_to) {
int32_t co_ret;
struct timeval tv;
sbintime_t sb;
tv.tv_sec = 0;
tv.tv_usec = 0;
while (need_new_to > HPTS_USEC_IN_SEC) {
tv.tv_sec++;
need_new_to -= HPTS_USEC_IN_SEC;
}
tv.tv_usec = need_new_to;
sb = tvtosbt(tv);
if (tcp_hpts_callout_skip_swi == 0) {
co_ret = callout_reset_sbt_on(&hpts->co, sb, 0,
hpts_timeout_swi, hpts, hpts->p_cpu,
(C_DIRECT_EXEC | C_PREL(tcp_hpts_precision)));
} else {
co_ret = callout_reset_sbt_on(&hpts->co, sb, 0,
hpts_timeout_dir, hpts,
hpts->p_cpu,
C_PREL(tcp_hpts_precision));
}
if (diag) {
diag->need_new_to = need_new_to;
diag->co_ret = co_ret;
}
}
} else {
#ifdef INVARIANTS
panic("Hpts:%p tp:%p already on hpts and add?", hpts, inp);
#endif
}
}
uint32_t
tcp_hpts_insert_diag(struct inpcb *inp, uint32_t slot, int32_t line, struct hpts_diag *diag)
{
struct tcp_hpts_entry *hpts;
uint32_t slot_on;
struct timeval tv;
/*
* We now return the next-slot the hpts will be on, beyond its
* current run (if up) or where it was when it stopped if it is
* sleeping.
*/
INP_WLOCK_ASSERT(inp);
hpts = tcp_hpts_lock(inp);
microuptime(&tv);
tcp_hpts_insert_locked(hpts, inp, slot, line, diag, &tv);
slot_on = hpts->p_nxt_slot;
mtx_unlock(&hpts->p_mtx);
return (slot_on);
}
uint32_t
__tcp_hpts_insert(struct inpcb *inp, uint32_t slot, int32_t line){
return (tcp_hpts_insert_diag(inp, slot, line, NULL));
}
int
__tcp_queue_to_input_locked(struct inpcb *inp, struct tcp_hpts_entry *hpts, int32_t line)
{
int32_t retval = 0;
HPTS_MTX_ASSERT(hpts);
if (inp->inp_in_input == 0) {
/* Ok we need to set it on the hpts in the current slot */
hpts_sane_input_insert(hpts, inp, line);
retval = 1;
if (hpts->p_hpts_active == 0) {
/*
* Activate the hpts if it is sleeping.
*/
retval = 2;
hpts->p_direct_wake = 1;
tcp_wakeinput(hpts);
}
} else if (hpts->p_hpts_active == 0) {
retval = 4;
hpts->p_direct_wake = 1;
tcp_wakeinput(hpts);
}
return (retval);
}
int32_t
__tcp_queue_to_input(struct inpcb *inp, int line)
{
struct tcp_hpts_entry *hpts;
int32_t ret;
hpts = tcp_input_lock(inp);
ret = __tcp_queue_to_input_locked(inp, hpts, line);
mtx_unlock(&hpts->p_mtx);
return (ret);
}
void
__tcp_set_inp_to_drop(struct inpcb *inp, uint16_t reason, int32_t line)
{
struct tcp_hpts_entry *hpts;
struct tcpcb *tp;
tp = intotcpcb(inp);
hpts = tcp_input_lock(tp->t_inpcb);
if (inp->inp_in_input == 0) {
/* Ok we need to set it on the hpts in the current slot */
hpts_sane_input_insert(hpts, inp, line);
if (hpts->p_hpts_active == 0) {
/*
* Activate the hpts if it is sleeping.
*/
hpts->p_direct_wake = 1;
tcp_wakeinput(hpts);
}
} else if (hpts->p_hpts_active == 0) {
hpts->p_direct_wake = 1;
tcp_wakeinput(hpts);
}
inp->inp_hpts_drop_reas = reason;
mtx_unlock(&hpts->p_mtx);
}
static uint16_t
hpts_random_cpu(struct inpcb *inp){
/*
* No flow type set distribute the load randomly.
*/
uint16_t cpuid;
uint32_t ran;
/*
* If one has been set use it i.e. we want both in and out on the
* same hpts.
*/
if (inp->inp_input_cpu_set) {
return (inp->inp_input_cpu);
} else if (inp->inp_hpts_cpu_set) {
return (inp->inp_hpts_cpu);
}
/* Nothing set use a random number */
ran = arc4random();
cpuid = (ran & 0xffff) % mp_ncpus;
return (cpuid);
}
static uint16_t
hpts_cpuid(struct inpcb *inp){
u_int cpuid;
#ifdef NUMA
struct hpts_domain_info *di;
#endif
/*
* If one has been set use it i.e. we want both in and out on the
* same hpts.
*/
if (inp->inp_input_cpu_set) {
return (inp->inp_input_cpu);
} else if (inp->inp_hpts_cpu_set) {
return (inp->inp_hpts_cpu);
}
/* If one is set the other must be the same */
#ifdef RSS
cpuid = rss_hash2cpuid(inp->inp_flowid, inp->inp_flowtype);
if (cpuid == NETISR_CPUID_NONE)
return (hpts_random_cpu(inp));
else
return (cpuid);
#else
/*
* We don't have a flowid -> cpuid mapping, so cheat and just map
* unknown cpuids to curcpu. Not the best, but apparently better
* than defaulting to swi 0.
*/
if (inp->inp_flowtype == M_HASHTYPE_NONE)
return (hpts_random_cpu(inp));
/*
* Hash to a thread based on the flowid. If we are using numa,
* then restrict the hash to the numa domain where the inp lives.
*/
#ifdef NUMA
if (tcp_bind_threads == 2 && inp->inp_numa_domain != M_NODOM) {
di = &hpts_domains[inp->inp_numa_domain];
cpuid = di->cpu[inp->inp_flowid % di->count];
} else
#endif
cpuid = inp->inp_flowid % mp_ncpus;
return (cpuid);
#endif
}
static void
tcp_drop_in_pkts(struct tcpcb *tp)
{
struct mbuf *m, *n;
m = tp->t_in_pkt;
if (m)
n = m->m_nextpkt;
else
n = NULL;
tp->t_in_pkt = NULL;
while (m) {
m_freem(m);
m = n;
if (m)
n = m->m_nextpkt;
}
}
/*
* Do NOT try to optimize the processing of inp's
* by first pulling off all the inp's into a temporary
* list (e.g. TAILQ_CONCAT). If you do that the subtle
* interactions of switching CPU's will kill because of
* problems in the linked list manipulation. Basically
* you would switch cpu's with the hpts mutex locked
* but then while you were processing one of the inp's
* some other one that you switch will get a new
* packet on the different CPU. It will insert it
* on the new hpts's input list. Creating a temporary
* link in the inp will not fix it either, since
* the other hpts will be doing the same thing and
* you will both end up using the temporary link.
*
* You will die in an ASSERT for tailq corruption if you
* run INVARIANTS or you will die horribly without
* INVARIANTS in some unknown way with a corrupt linked
* list.
*/
static void
tcp_input_data(struct tcp_hpts_entry *hpts, struct timeval *tv)
{
struct tcpcb *tp;
struct inpcb *inp;
uint16_t drop_reason;
int16_t set_cpu;
uint32_t did_prefetch = 0;
int dropped;
HPTS_MTX_ASSERT(hpts);
NET_EPOCH_ASSERT();
while ((inp = TAILQ_FIRST(&hpts->p_input)) != NULL) {
HPTS_MTX_ASSERT(hpts);
hpts_sane_input_remove(hpts, inp, 0);
if (inp->inp_input_cpu_set == 0) {
set_cpu = 1;
} else {
set_cpu = 0;
}
hpts->p_inp = inp;
drop_reason = inp->inp_hpts_drop_reas;
inp->inp_in_input = 0;
mtx_unlock(&hpts->p_mtx);
INP_WLOCK(inp);
#ifdef VIMAGE
CURVNET_SET(inp->inp_vnet);
#endif
if ((inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) ||
(inp->inp_flags2 & INP_FREED)) {
out:
hpts->p_inp = NULL;
if (in_pcbrele_wlocked(inp) == 0) {
INP_WUNLOCK(inp);
}
#ifdef VIMAGE
CURVNET_RESTORE();
#endif
mtx_lock(&hpts->p_mtx);
continue;
}
tp = intotcpcb(inp);
if ((tp == NULL) || (tp->t_inpcb == NULL)) {
goto out;
}
if (drop_reason) {
/* This tcb is being destroyed for drop_reason */
tcp_drop_in_pkts(tp);
tp = tcp_drop(tp, drop_reason);
if (tp == NULL) {
INP_WLOCK(inp);
}
if (in_pcbrele_wlocked(inp) == 0)
INP_WUNLOCK(inp);
#ifdef VIMAGE
CURVNET_RESTORE();
#endif
mtx_lock(&hpts->p_mtx);
continue;
}
if (set_cpu) {
/*
* Setup so the next time we will move to the right
* CPU. This should be a rare event. It will
* sometimes happens when we are the client side
* (usually not the server). Somehow tcp_output()
* gets called before the tcp_do_segment() sets the
* intial state. This means the r_cpu and r_hpts_cpu
* is 0. We get on the hpts, and then tcp_input()
* gets called setting up the r_cpu to the correct
* value. The hpts goes off and sees the mis-match.
* We simply correct it here and the CPU will switch
* to the new hpts nextime the tcb gets added to the
* the hpts (not this time) :-)
*/
tcp_set_hpts(inp);
}
if (tp->t_fb_ptr != NULL) {
kern_prefetch(tp->t_fb_ptr, &did_prefetch);
did_prefetch = 1;
}
if ((inp->inp_flags2 & INP_SUPPORTS_MBUFQ) && tp->t_in_pkt) {
if (inp->inp_in_input)
tcp_hpts_remove(inp, HPTS_REMOVE_INPUT);
dropped = (*tp->t_fb->tfb_do_queued_segments)(inp->inp_socket, tp, 0);
if (dropped) {
/* Re-acquire the wlock so we can release the reference */
INP_WLOCK(inp);
}
} else if (tp->t_in_pkt) {
/*
* We reach here only if we had a
* stack that supported INP_SUPPORTS_MBUFQ
* and then somehow switched to a stack that
* does not. The packets are basically stranded
* and would hang with the connection until
* cleanup without this code. Its not the
* best way but I know of no other way to
* handle it since the stack needs functions
* it does not have to handle queued packets.
*/
tcp_drop_in_pkts(tp);
}
if (in_pcbrele_wlocked(inp) == 0)
INP_WUNLOCK(inp);
INP_UNLOCK_ASSERT(inp);
#ifdef VIMAGE
CURVNET_RESTORE();
#endif
mtx_lock(&hpts->p_mtx);
hpts->p_inp = NULL;
}
}
static void
tcp_hptsi(struct tcp_hpts_entry *hpts)
{
struct tcpcb *tp;
struct inpcb *inp = NULL, *ninp;
struct timeval tv;
int32_t ticks_to_run, i, error;
int32_t paced_cnt = 0;
int32_t loop_cnt = 0;
int32_t did_prefetch = 0;
int32_t prefetch_ninp = 0;
int32_t prefetch_tp = 0;
int32_t wrap_loop_cnt = 0;
int16_t set_cpu;
HPTS_MTX_ASSERT(hpts);
NET_EPOCH_ASSERT();
/* record previous info for any logging */
hpts->saved_lasttick = hpts->p_lasttick;
hpts->saved_curtick = hpts->p_curtick;
hpts->saved_curslot = hpts->p_cur_slot;
hpts->saved_prev_slot = hpts->p_prev_slot;
hpts->p_lasttick = hpts->p_curtick;
hpts->p_curtick = tcp_gethptstick(&tv);
hpts->p_cur_slot = tick_to_wheel(hpts->p_curtick);
if ((hpts->p_on_queue_cnt == 0) ||
(hpts->p_lasttick == hpts->p_curtick)) {
/*
* No time has yet passed,
* or nothing to do.
*/
hpts->p_prev_slot = hpts->p_cur_slot;
hpts->p_lasttick = hpts->p_curtick;
goto no_run;
}
again:
hpts->p_wheel_complete = 0;
HPTS_MTX_ASSERT(hpts);
ticks_to_run = hpts_ticks_diff(hpts->p_prev_slot, hpts->p_cur_slot);
if (((hpts->p_curtick - hpts->p_lasttick) > ticks_to_run) &&
(hpts->p_on_queue_cnt != 0)) {
/*
* Wheel wrap is occuring, basically we
* are behind and the distance between
* run's has spread so much it has exceeded
* the time on the wheel (1.024 seconds). This
* is ugly and should NOT be happening. We
* need to run the entire wheel. We last processed
* p_prev_slot, so that needs to be the last slot
* we run. The next slot after that should be our
* reserved first slot for new, and then starts
* the running postion. Now the problem is the
* reserved "not to yet" place does not exist
* and there may be inp's in there that need
* running. We can merge those into the
* first slot at the head.
*/
wrap_loop_cnt++;
hpts->p_nxt_slot = hpts_tick(hpts->p_prev_slot, 1);
hpts->p_runningtick = hpts_tick(hpts->p_prev_slot, 2);
/*
* Adjust p_cur_slot to be where we are starting from
* hopefully we will catch up (fat chance if something
* is broken this bad :( )
*/
hpts->p_cur_slot = hpts->p_prev_slot;
/*
* The next slot has guys to run too, and that would
* be where we would normally start, lets move them into
* the next slot (p_prev_slot + 2) so that we will
* run them, the extra 10usecs of late (by being
* put behind) does not really matter in this situation.
*/
#ifdef INVARIANTS
/*
* To prevent a panic we need to update the inpslot to the
* new location. This is safe since it takes both the
* INP lock and the pacer mutex to change the inp_hptsslot.
*/
TAILQ_FOREACH(inp, &hpts->p_hptss[hpts->p_nxt_slot], inp_hpts) {
inp->inp_hptsslot = hpts->p_runningtick;
}
#endif
TAILQ_CONCAT(&hpts->p_hptss[hpts->p_runningtick],
&hpts->p_hptss[hpts->p_nxt_slot], inp_hpts);
ticks_to_run = NUM_OF_HPTSI_SLOTS - 1;
counter_u64_add(wheel_wrap, 1);
} else {
/*
* Nxt slot is always one after p_runningtick though
* its not used usually unless we are doing wheel wrap.
*/
hpts->p_nxt_slot = hpts->p_prev_slot;
hpts->p_runningtick = hpts_tick(hpts->p_prev_slot, 1);
}
#ifdef INVARIANTS
if (TAILQ_EMPTY(&hpts->p_input) &&
(hpts->p_on_inqueue_cnt != 0)) {
panic("tp:%p in_hpts input empty but cnt:%d",
hpts, hpts->p_on_inqueue_cnt);
}
#endif
HPTS_MTX_ASSERT(hpts);
if (hpts->p_on_queue_cnt == 0) {
goto no_one;
}
HPTS_MTX_ASSERT(hpts);
for (i = 0; i < ticks_to_run; i++) {
/*
* Calculate our delay, if there are no extra ticks there
* was not any (i.e. if ticks_to_run == 1, no delay).
*/
hpts->p_delayed_by = (ticks_to_run - (i + 1)) * HPTS_TICKS_PER_USEC;
HPTS_MTX_ASSERT(hpts);
while ((inp = TAILQ_FIRST(&hpts->p_hptss[hpts->p_runningtick])) != NULL) {
/* For debugging */
hpts->p_inp = inp;
paced_cnt++;
#ifdef INVARIANTS
if (hpts->p_runningtick != inp->inp_hptsslot) {
panic("Hpts:%p inp:%p slot mis-aligned %u vs %u",
hpts, inp, hpts->p_runningtick, inp->inp_hptsslot);
}
#endif
/* Now pull it */
if (inp->inp_hpts_cpu_set == 0) {
set_cpu = 1;
} else {
set_cpu = 0;
}
hpts_sane_pace_remove(hpts, inp, &hpts->p_hptss[hpts->p_runningtick], 0);
if ((ninp = TAILQ_FIRST(&hpts->p_hptss[hpts->p_runningtick])) != NULL) {
/* We prefetch the next inp if possible */
kern_prefetch(ninp, &prefetch_ninp);
prefetch_ninp = 1;
}
if (inp->inp_hpts_request) {
/*
* This guy is deferred out further in time
* then our wheel had available on it.
* Push him back on the wheel or run it
* depending.
*/
uint32_t maxticks, last_tick, remaining_slots;
remaining_slots = ticks_to_run - (i + 1);
if (inp->inp_hpts_request > remaining_slots) {
/*
* How far out can we go?
*/
maxticks = max_ticks_available(hpts, hpts->p_cur_slot, &last_tick);
if (maxticks >= inp->inp_hpts_request) {
/* we can place it finally to be processed */
inp->inp_hptsslot = hpts_tick(hpts->p_runningtick, inp->inp_hpts_request);
inp->inp_hpts_request = 0;
} else {
/* Work off some more time */
inp->inp_hptsslot = last_tick;
inp->inp_hpts_request-= maxticks;
}
hpts_sane_pace_insert(hpts, inp, &hpts->p_hptss[inp->inp_hptsslot], __LINE__, 1);
hpts->p_inp = NULL;
continue;
}
inp->inp_hpts_request = 0;
/* Fall through we will so do it now */
}
/*
* We clear the hpts flag here after dealing with
* remaining slots. This way anyone looking with the
* TCB lock will see its on the hpts until just
* before we unlock.
*/
inp->inp_in_hpts = 0;
mtx_unlock(&hpts->p_mtx);
INP_WLOCK(inp);
if (in_pcbrele_wlocked(inp)) {
mtx_lock(&hpts->p_mtx);
hpts->p_inp = NULL;
continue;
}
if ((inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) ||
(inp->inp_flags2 & INP_FREED)) {
out_now:
#ifdef INVARIANTS
if (mtx_owned(&hpts->p_mtx)) {
panic("Hpts:%p owns mtx prior-to lock line:%d",
hpts, __LINE__);
}
#endif
INP_WUNLOCK(inp);
mtx_lock(&hpts->p_mtx);
hpts->p_inp = NULL;
continue;
}
tp = intotcpcb(inp);
if ((tp == NULL) || (tp->t_inpcb == NULL)) {
goto out_now;
}
if (set_cpu) {
/*
* Setup so the next time we will move to
* the right CPU. This should be a rare
* event. It will sometimes happens when we
* are the client side (usually not the
* server). Somehow tcp_output() gets called
* before the tcp_do_segment() sets the
* intial state. This means the r_cpu and
* r_hpts_cpu is 0. We get on the hpts, and
* then tcp_input() gets called setting up
* the r_cpu to the correct value. The hpts
* goes off and sees the mis-match. We
* simply correct it here and the CPU will
* switch to the new hpts nextime the tcb
* gets added to the the hpts (not this one)
* :-)
*/
tcp_set_hpts(inp);
}
#ifdef VIMAGE
CURVNET_SET(inp->inp_vnet);
#endif
/* Lets do any logging that we might want to */
if (hpts_does_tp_logging && (tp->t_logstate != TCP_LOG_STATE_OFF)) {
tcp_hpts_log(hpts, tp, &tv, ticks_to_run, i);
}
/*
* There is a hole here, we get the refcnt on the
* inp so it will still be preserved but to make
* sure we can get the INP we need to hold the p_mtx
* above while we pull out the tp/inp, as long as
* fini gets the lock first we are assured of having
* a sane INP we can lock and test.
*/
#ifdef INVARIANTS
if (mtx_owned(&hpts->p_mtx)) {
panic("Hpts:%p owns mtx before tcp-output:%d",
hpts, __LINE__);
}
#endif
if (tp->t_fb_ptr != NULL) {
kern_prefetch(tp->t_fb_ptr, &did_prefetch);
did_prefetch = 1;
}
if ((inp->inp_flags2 & INP_SUPPORTS_MBUFQ) && tp->t_in_pkt) {
error = (*tp->t_fb->tfb_do_queued_segments)(inp->inp_socket, tp, 0);
if (error) {
/* The input killed the connection */
goto skip_pacing;
}
}
inp->inp_hpts_calls = 1;
error = tp->t_fb->tfb_tcp_output(tp);
inp->inp_hpts_calls = 0;
if (ninp && ninp->inp_ppcb) {
/*
* If we have a nxt inp, see if we can
* prefetch its ppcb. Note this may seem
* "risky" since we have no locks (other
* than the previous inp) and there no
* assurance that ninp was not pulled while
* we were processing inp and freed. If this
* occured it could mean that either:
*
* a) Its NULL (which is fine we won't go
* here) <or> b) Its valid (which is cool we
* will prefetch it) <or> c) The inp got
* freed back to the slab which was
* reallocated. Then the piece of memory was
* re-used and something else (not an
* address) is in inp_ppcb. If that occurs
* we don't crash, but take a TLB shootdown
* performance hit (same as if it was NULL
* and we tried to pre-fetch it).
*
* Considering that the likelyhood of <c> is
* quite rare we will take a risk on doing
* this. If performance drops after testing
* we can always take this out. NB: the
* kern_prefetch on amd64 actually has
* protection against a bad address now via
* the DMAP_() tests. This will prevent the
* TLB hit, and instead if <c> occurs just
* cause us to load cache with a useless
* address (to us).
*/
kern_prefetch(ninp->inp_ppcb, &prefetch_tp);
prefetch_tp = 1;
}
INP_WUNLOCK(inp);
skip_pacing:
#ifdef VIMAGE
CURVNET_RESTORE();
#endif
INP_UNLOCK_ASSERT(inp);
#ifdef INVARIANTS
if (mtx_owned(&hpts->p_mtx)) {
panic("Hpts:%p owns mtx prior-to lock line:%d",
hpts, __LINE__);
}
#endif
mtx_lock(&hpts->p_mtx);
hpts->p_inp = NULL;
}
HPTS_MTX_ASSERT(hpts);
hpts->p_inp = NULL;
hpts->p_runningtick++;
if (hpts->p_runningtick >= NUM_OF_HPTSI_SLOTS) {
hpts->p_runningtick = 0;
}
}
no_one:
HPTS_MTX_ASSERT(hpts);
hpts->p_delayed_by = 0;
/*
* Check to see if we took an excess amount of time and need to run
* more ticks (if we did not hit eno-bufs).
*/
#ifdef INVARIANTS
if (TAILQ_EMPTY(&hpts->p_input) &&
(hpts->p_on_inqueue_cnt != 0)) {
panic("tp:%p in_hpts input empty but cnt:%d",
hpts, hpts->p_on_inqueue_cnt);
}
#endif
hpts->p_prev_slot = hpts->p_cur_slot;
hpts->p_lasttick = hpts->p_curtick;
if (loop_cnt > max_pacer_loops) {
/*
* Something is serious slow we have
* looped through processing the wheel
* and by the time we cleared the
* needs to run max_pacer_loops time
* we still needed to run. That means
* the system is hopelessly behind and
* can never catch up :(
*
* We will just lie to this thread
* and let it thing p_curtick is
* correct. When it next awakens
* it will find itself further behind.
*/
counter_u64_add(hpts_hopelessly_behind, 1);
goto no_run;
}
hpts->p_curtick = tcp_gethptstick(&tv);
hpts->p_cur_slot = tick_to_wheel(hpts->p_curtick);
if ((wrap_loop_cnt < 2) &&
(hpts->p_lasttick != hpts->p_curtick)) {
counter_u64_add(hpts_loops, 1);
loop_cnt++;
goto again;
}
no_run:
/*
* Set flag to tell that we are done for
* any slot input that happens during
* input.
*/
hpts->p_wheel_complete = 1;
/*
* Run any input that may be there not covered
* in running data.
*/
if (!TAILQ_EMPTY(&hpts->p_input)) {
tcp_input_data(hpts, &tv);
/*
* Now did we spend too long running
* input and need to run more ticks?
*/
KASSERT(hpts->p_prev_slot == hpts->p_cur_slot,
("H:%p p_prev_slot:%u not equal to p_cur_slot:%u", hpts,
hpts->p_prev_slot, hpts->p_cur_slot));
KASSERT(hpts->p_lasttick == hpts->p_curtick,
("H:%p p_lasttick:%u not equal to p_curtick:%u", hpts,
hpts->p_lasttick, hpts->p_curtick));
hpts->p_curtick = tcp_gethptstick(&tv);
if (hpts->p_lasttick != hpts->p_curtick) {
counter_u64_add(hpts_loops, 1);
hpts->p_cur_slot = tick_to_wheel(hpts->p_curtick);
goto again;
}
}
{
uint32_t t = 0, i, fnd = 0;
if ((hpts->p_on_queue_cnt) && (wrap_loop_cnt < 2)) {
/*
* Find next slot that is occupied and use that to
* be the sleep time.
*/
for (i = 0, t = hpts_tick(hpts->p_cur_slot, 1); i < NUM_OF_HPTSI_SLOTS; i++) {
if (TAILQ_EMPTY(&hpts->p_hptss[t]) == 0) {
fnd = 1;
break;
}
t = (t + 1) % NUM_OF_HPTSI_SLOTS;
}
if (fnd) {
hpts->p_hpts_sleep_time = min((i + 1), hpts_sleep_max);
} else {
#ifdef INVARIANTS
panic("Hpts:%p cnt:%d but none found", hpts, hpts->p_on_queue_cnt);
#endif
counter_u64_add(back_tosleep, 1);
hpts->p_on_queue_cnt = 0;
goto non_found;
}
} else if (wrap_loop_cnt >= 2) {
/* Special case handling */
hpts->p_hpts_sleep_time = tcp_min_hptsi_time;
} else {
/* No one on the wheel sleep for all but 400 slots or sleep max */
non_found:
hpts->p_hpts_sleep_time = hpts_sleep_max;
}
}
}
void
__tcp_set_hpts(struct inpcb *inp, int32_t line)
{
struct tcp_hpts_entry *hpts;
INP_WLOCK_ASSERT(inp);
hpts = tcp_hpts_lock(inp);
if ((inp->inp_in_hpts == 0) &&
(inp->inp_hpts_cpu_set == 0)) {
inp->inp_hpts_cpu = hpts_cpuid(inp);
inp->inp_hpts_cpu_set = 1;
}
mtx_unlock(&hpts->p_mtx);
hpts = tcp_input_lock(inp);
if ((inp->inp_input_cpu_set == 0) &&
(inp->inp_in_input == 0)) {
inp->inp_input_cpu = hpts_cpuid(inp);
inp->inp_input_cpu_set = 1;
}
mtx_unlock(&hpts->p_mtx);
}
uint16_t
tcp_hpts_delayedby(struct inpcb *inp){
return (tcp_pace.rp_ent[inp->inp_hpts_cpu]->p_delayed_by);
}
static void
tcp_hpts_thread(void *ctx)
{
struct tcp_hpts_entry *hpts;
struct epoch_tracker et;
struct timeval tv;
sbintime_t sb;
hpts = (struct tcp_hpts_entry *)ctx;
mtx_lock(&hpts->p_mtx);
if (hpts->p_direct_wake) {
/* Signaled by input */
callout_stop(&hpts->co);
} else {
/* Timed out */
if (callout_pending(&hpts->co) ||
!callout_active(&hpts->co)) {
mtx_unlock(&hpts->p_mtx);
return;
}
callout_deactivate(&hpts->co);
}
hpts->p_hpts_wake_scheduled = 0;
hpts->p_hpts_active = 1;
NET_EPOCH_ENTER(et);
tcp_hptsi(hpts);
NET_EPOCH_EXIT(et);
HPTS_MTX_ASSERT(hpts);
tv.tv_sec = 0;
tv.tv_usec = hpts->p_hpts_sleep_time * HPTS_TICKS_PER_USEC;
if (tcp_min_hptsi_time && (tv.tv_usec < tcp_min_hptsi_time)) {
hpts->overidden_sleep = tv.tv_usec;
tv.tv_usec = tcp_min_hptsi_time;
hpts->p_on_min_sleep = 1;
} else {
/* Clear the min sleep flag */
hpts->overidden_sleep = 0;
hpts->p_on_min_sleep = 0;
}
hpts->p_hpts_active = 0;
sb = tvtosbt(tv);
if (tcp_hpts_callout_skip_swi == 0) {
callout_reset_sbt_on(&hpts->co, sb, 0,
hpts_timeout_swi, hpts, hpts->p_cpu,
(C_DIRECT_EXEC | C_PREL(tcp_hpts_precision)));
} else {
callout_reset_sbt_on(&hpts->co, sb, 0,
hpts_timeout_dir, hpts,
hpts->p_cpu,
C_PREL(tcp_hpts_precision));
}
hpts->p_direct_wake = 0;
mtx_unlock(&hpts->p_mtx);
}
#undef timersub
static void
tcp_init_hptsi(void *st)
{
int32_t i, j, error, bound = 0, created = 0;
size_t sz, asz;
struct timeval tv;
sbintime_t sb;
struct tcp_hpts_entry *hpts;
struct pcpu *pc;
cpuset_t cs;
char unit[16];
uint32_t ncpus = mp_ncpus ? mp_ncpus : MAXCPU;
int count, domain;
tcp_pace.rp_proc = NULL;
tcp_pace.rp_num_hptss = ncpus;
hpts_hopelessly_behind = counter_u64_alloc(M_WAITOK);
hpts_loops = counter_u64_alloc(M_WAITOK);
back_tosleep = counter_u64_alloc(M_WAITOK);
combined_wheel_wrap = counter_u64_alloc(M_WAITOK);
wheel_wrap = counter_u64_alloc(M_WAITOK);
sz = (tcp_pace.rp_num_hptss * sizeof(struct tcp_hpts_entry *));
tcp_pace.rp_ent = malloc(sz, M_TCPHPTS, M_WAITOK | M_ZERO);
asz = sizeof(struct hptsh) * NUM_OF_HPTSI_SLOTS;
for (i = 0; i < tcp_pace.rp_num_hptss; i++) {
tcp_pace.rp_ent[i] = malloc(sizeof(struct tcp_hpts_entry),
M_TCPHPTS, M_WAITOK | M_ZERO);
tcp_pace.rp_ent[i]->p_hptss = malloc(asz,
M_TCPHPTS, M_WAITOK);
hpts = tcp_pace.rp_ent[i];
/*
* Init all the hpts structures that are not specifically
* zero'd by the allocations. Also lets attach them to the
* appropriate sysctl block as well.
*/
mtx_init(&hpts->p_mtx, "tcp_hpts_lck",
"hpts", MTX_DEF | MTX_DUPOK);
TAILQ_INIT(&hpts->p_input);
for (j = 0; j < NUM_OF_HPTSI_SLOTS; j++) {
TAILQ_INIT(&hpts->p_hptss[j]);
}
sysctl_ctx_init(&hpts->hpts_ctx);
sprintf(unit, "%d", i);
hpts->hpts_root = SYSCTL_ADD_NODE(&hpts->hpts_ctx,
SYSCTL_STATIC_CHILDREN(_net_inet_tcp_hpts),
OID_AUTO,
unit,
CTLFLAG_RW, 0,
"");
SYSCTL_ADD_INT(&hpts->hpts_ctx,
SYSCTL_CHILDREN(hpts->hpts_root),
OID_AUTO, "in_qcnt", CTLFLAG_RD,
&hpts->p_on_inqueue_cnt, 0,
"Count TCB's awaiting input processing");
SYSCTL_ADD_INT(&hpts->hpts_ctx,
SYSCTL_CHILDREN(hpts->hpts_root),
OID_AUTO, "out_qcnt", CTLFLAG_RD,
&hpts->p_on_queue_cnt, 0,
"Count TCB's awaiting output processing");
SYSCTL_ADD_U16(&hpts->hpts_ctx,
SYSCTL_CHILDREN(hpts->hpts_root),
OID_AUTO, "active", CTLFLAG_RD,
&hpts->p_hpts_active, 0,
"Is the hpts active");
SYSCTL_ADD_UINT(&hpts->hpts_ctx,
SYSCTL_CHILDREN(hpts->hpts_root),
OID_AUTO, "curslot", CTLFLAG_RD,
&hpts->p_cur_slot, 0,
"What the current running pacers goal");
SYSCTL_ADD_UINT(&hpts->hpts_ctx,
SYSCTL_CHILDREN(hpts->hpts_root),
OID_AUTO, "runtick", CTLFLAG_RD,
&hpts->p_runningtick, 0,
"What the running pacers current slot is");
SYSCTL_ADD_UINT(&hpts->hpts_ctx,
SYSCTL_CHILDREN(hpts->hpts_root),
OID_AUTO, "curtick", CTLFLAG_RD,
&hpts->p_curtick, 0,
"What the running pacers last tick mapped to the wheel was");
hpts->p_hpts_sleep_time = hpts_sleep_max;
hpts->p_num = i;
hpts->p_curtick = tcp_gethptstick(&tv);
hpts->p_prev_slot = hpts->p_cur_slot = tick_to_wheel(hpts->p_curtick);
hpts->p_cpu = 0xffff;
hpts->p_nxt_slot = hpts_tick(hpts->p_cur_slot, 1);
callout_init(&hpts->co, 1);
}
/* Don't try to bind to NUMA domains if we don't have any */
if (vm_ndomains == 1 && tcp_bind_threads == 2)
tcp_bind_threads = 0;
/*
* Now lets start ithreads to handle the hptss.
*/
CPU_FOREACH(i) {
hpts = tcp_pace.rp_ent[i];
hpts->p_cpu = i;
error = swi_add(&hpts->ie, "hpts",
tcp_hpts_thread, (void *)hpts,
SWI_NET, INTR_MPSAFE, &hpts->ie_cookie);
if (error) {
panic("Can't add hpts:%p i:%d err:%d",
hpts, i, error);
}
created++;
if (tcp_bind_threads == 1) {
if (intr_event_bind(hpts->ie, i) == 0)
bound++;
} else if (tcp_bind_threads == 2) {
pc = pcpu_find(i);
domain = pc->pc_domain;
CPU_COPY(&cpuset_domain[domain], &cs);
if (intr_event_bind_ithread_cpuset(hpts->ie, &cs)
== 0) {
bound++;
count = hpts_domains[domain].count;
hpts_domains[domain].cpu[count] = i;
hpts_domains[domain].count++;
}
}
tv.tv_sec = 0;
tv.tv_usec = hpts->p_hpts_sleep_time * HPTS_TICKS_PER_USEC;
sb = tvtosbt(tv);
if (tcp_hpts_callout_skip_swi == 0) {
callout_reset_sbt_on(&hpts->co, sb, 0,
hpts_timeout_swi, hpts, hpts->p_cpu,
(C_DIRECT_EXEC | C_PREL(tcp_hpts_precision)));
} else {
callout_reset_sbt_on(&hpts->co, sb, 0,
hpts_timeout_dir, hpts,
hpts->p_cpu,
C_PREL(tcp_hpts_precision));
}
}
/*
* If we somehow have an empty domain, fall back to choosing
* among all htps threads.
*/
for (i = 0; i < vm_ndomains; i++) {
if (hpts_domains[i].count == 0) {
tcp_bind_threads = 0;
break;
}
}
printf("TCP Hpts created %d swi interrupt threads and bound %d to %s\n",
created, bound,
tcp_bind_threads == 2 ? "NUMA domains" : "cpus");
}
SYSINIT(tcphptsi, SI_SUB_KTHREAD_IDLE, SI_ORDER_ANY, tcp_init_hptsi, NULL);
MODULE_VERSION(tcphpts, 1);
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