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freebsd-skq/sys/netinet/tcp_hpts.c
mmacy 14de8a2820 epoch(9): allow preemptible epochs to compose 
- Add tracker argument to preemptible epochs
- Inline epoch read path in kernel and tied modules
- Change in_epoch to take an epoch as argument
- Simplify tfb_tcp_do_segment to not take a ti_locked argument,
  there's no longer any benefit to dropping the pcbinfo lock
  and trying to do so just adds an error prone branchfest to
  these functions
- Remove cases of same function recursion on the epoch as
  recursing is no longer free.
- Remove the the TAILQ_ENTRY and epoch_section from struct
  thread as the tracker field is now stack or heap allocated
  as appropriate.

Tested by: pho and Limelight Networks
Reviewed by: kbowling at llnw dot com
Sponsored by: Limelight Networks
Differential Revision: https://reviews.freebsd.org/D16066
2018-07-04 02:47:16 +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_ipsec.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 for, 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 tcp_hpts system will call tcp_output in one of two forms,
* it will first check to see if the stack as defined a
* tfb_tcp_output_wtime() function, if so that is the routine it
* will call, if that function is not defined then it will call the
* tfb_tcp_output() function. The only difference between these
* two calls is that the former passes the time in to the function
* so the function does not have to access the time (which tcp_hpts
* already has). What these functions do is of course totally up
* to the individual tcp stack.
*
* 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.
*
* So in order to use the input redirection function the
* stack changes its tcp_do_segment() routine to instead
* of process the data call the function:
*
* tcp_queue_pkt_to_input()
*
* You will note that the arguments to this function look
* a lot like tcp_do_segments's arguments. This function
* will assure that the tcp_hpts system will
* call the functions tfb_tcp_hpts_do_segment() from the
* correct CPU. Note that multiple calls can get pushed
* into the tcp_hpts system this will be indicated by
* the next to last argument to tfb_tcp_hpts_do_segment()
* (nxt_pkt). If nxt_pkt is a 1 then another packet is
* coming. If nxt_pkt is a 0 then this is the last call
* that the tcp_hpts system has available for the tcp stack.
*
* The other point of the input system is to be able to safely
* drop a tcp connection without worrying about the recursive
* locking that may be occuring 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 <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>
#ifdef tcpdebug
#include <netinet/tcp_debug.h>
#endif /* tcpdebug */
#ifdef tcp_offload
#include <netinet/tcp_offload.h>
#endif
#ifdef ipsec
#include <netipsec/ipsec.h>
#include <netipsec/ipsec6.h>
#endif /* ipsec */
#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 = 0;
#endif
TUNABLE_INT("net.inet.tcp.bind_hptss", &tcp_bind_threads);
static uint32_t tcp_hpts_logging_size = DEFAULT_HPTS_LOG;
TUNABLE_INT("net.inet.tcp.hpts_logging_sz", &tcp_hpts_logging_size);
static struct tcp_hptsi tcp_pace;
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, struct timeval *ctick);
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 logging_on = 0;
static int32_t hpts_sleep_max = (NUM_OF_HPTSI_SLOTS - 2);
static int32_t tcp_hpts_precision = 120;
SYSCTL_INT(_net_inet_tcp_hpts, OID_AUTO, precision, CTLFLAG_RW,
&tcp_hpts_precision, 120,
"Value for PRE() precision of callout");
SYSCTL_INT(_net_inet_tcp_hpts, OID_AUTO, logging, CTLFLAG_RW,
&logging_on, 0,
"Turn on logging if compiled in");
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");
static int32_t in_newts_every_tcb = 0;
SYSCTL_INT(_net_inet_tcp_hpts, OID_AUTO, in_tsperpcb, CTLFLAG_RW,
&in_newts_every_tcb, 0,
"Do we have a new cts every tcb we process for input");
static int32_t in_ts_percision = 0;
SYSCTL_INT(_net_inet_tcp_hpts, OID_AUTO, in_tspercision, CTLFLAG_RW,
&in_ts_percision, 0,
"Do we use percise timestamp for clients on input");
static int32_t out_newts_every_tcb = 0;
SYSCTL_INT(_net_inet_tcp_hpts, OID_AUTO, out_tsperpcb, CTLFLAG_RW,
&out_newts_every_tcb, 0,
"Do we have a new cts every tcb we process for output");
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, maxsleep, CTLFLAG_RW,
&hpts_sleep_max, 0,
"The maximum time the hpts will sleep <1 - 254>");
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_it(struct tcp_hpts_entry *hpts, struct inpcb *inp, int event, uint32_t slot,
uint32_t ticknow, int32_t line)
{
struct hpts_log *pl;
HPTS_MTX_ASSERT(hpts);
if (hpts->p_log == NULL)
return;
pl = &hpts->p_log[hpts->p_log_at];
hpts->p_log_at++;
if (hpts->p_log_at >= hpts->p_logsize) {
hpts->p_log_at = 0;
hpts->p_log_wrapped = 1;
}
pl->inp = inp;
if (inp) {
pl->t_paceslot = inp->inp_hptsslot;
pl->t_hptsreq = inp->inp_hpts_request;
pl->p_onhpts = inp->inp_in_hpts;
pl->p_oninput = inp->inp_in_input;
} else {
pl->t_paceslot = 0;
pl->t_hptsreq = 0;
pl->p_onhpts = 0;
pl->p_oninput = 0;
}
pl->is_notempty = 1;
pl->event = event;
pl->line = line;
pl->cts = tcp_get_usecs(NULL);
pl->p_curtick = hpts->p_curtick;
pl->p_prevtick = hpts->p_prevtick;
pl->p_on_queue_cnt = hpts->p_on_queue_cnt;
pl->ticknow = ticknow;
pl->slot_req = slot;
pl->p_nxt_slot = hpts->p_nxt_slot;
pl->p_cur_slot = hpts->p_cur_slot;
pl->p_hpts_sleep_time = hpts->p_hpts_sleep_time;
pl->p_flags = (hpts->p_cpu & 0x7f);
pl->p_flags <<= 7;
pl->p_flags |= (hpts->p_num & 0x7f);
pl->p_flags <<= 2;
if (hpts->p_hpts_active) {
pl->p_flags |= HPTS_HPTS_ACTIVE;
}
}
#define tcp_hpts_log_it(a, b, c, d, e) __tcp_hpts_log_it(a, b, c, d, e, __LINE__)
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);
}
if (TAILQ_EMPTY(head) &&
(hpts->p_on_queue_cnt != 0)) {
/* We should not be empty with a queue count */
panic("%s hpts:%p hpts bucket empty but cnt:%d",
__FUNCTION__, hpts, hpts->p_on_queue_cnt);
}
#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 int
sysctl_tcp_hpts_log(SYSCTL_HANDLER_ARGS)
{
struct tcp_hpts_entry *hpts;
size_t sz;
int32_t logging_was, i;
int32_t error = 0;
/*
* HACK: Turn off logging so no locks are required this really needs
* a memory barrier :)
*/
logging_was = logging_on;
logging_on = 0;
if (!req->oldptr) {
/* How much? */
sz = 0;
for (i = 0; i < tcp_pace.rp_num_hptss; i++) {
hpts = tcp_pace.rp_ent[i];
if (hpts->p_log == NULL)
continue;
sz += (sizeof(struct hpts_log) * hpts->p_logsize);
}
error = SYSCTL_OUT(req, 0, sz);
} else {
for (i = 0; i < tcp_pace.rp_num_hptss; i++) {
hpts = tcp_pace.rp_ent[i];
if (hpts->p_log == NULL)
continue;
if (hpts->p_log_wrapped)
sz = (sizeof(struct hpts_log) * hpts->p_logsize);
else
sz = (sizeof(struct hpts_log) * hpts->p_log_at);
error = SYSCTL_OUT(req, hpts->p_log, sz);
}
}
logging_on = logging_was;
return error;
}
SYSCTL_PROC(_net_inet_tcp_hpts, OID_AUTO, log, CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE,
0, 0, sysctl_tcp_hpts_log, "A", "tcp hptsi log");
static void
tcp_wakehpts(struct tcp_hpts_entry *hpts)
{
HPTS_MTX_ASSERT(hpts);
swi_sched(hpts->ie_cookie, 0);
if (hpts->p_hpts_active == 2) {
/* Rare sleeping on a ENOBUF */
wakeup_one(hpts);
}
}
static void
tcp_wakeinput(struct tcp_hpts_entry *hpts)
{
HPTS_MTX_ASSERT(hpts);
swi_sched(hpts->ie_cookie, 0);
if (hpts->p_hpts_active == 2) {
/* Rare sleeping on a ENOBUF */
wakeup_one(hpts);
}
}
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 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(struct tcp_hpts_entry *hpts, int32_t plus)
{
return ((hpts->p_prevtick + plus) % NUM_OF_HPTSI_SLOTS);
}
static int
tcp_queue_to_hpts_immediate_locked(struct inpcb *inp, struct tcp_hpts_entry *hpts, int32_t line, int32_t noref)
{
int32_t need_wake = 0;
uint32_t ticknow = 0;
HPTS_MTX_ASSERT(hpts);
if (inp->inp_in_hpts == 0) {
/* Ok we need to set it on the hpts in the current slot */
if (hpts->p_hpts_active == 0) {
/* A sleeping hpts we want in next slot to run */
if (logging_on) {
tcp_hpts_log_it(hpts, inp, HPTSLOG_INSERT_SLEEPER, 0,
hpts_tick(hpts, 1));
}
inp->inp_hptsslot = hpts_tick(hpts, 1);
inp->inp_hpts_request = 0;
if (logging_on) {
tcp_hpts_log_it(hpts, inp, HPTSLOG_SLEEP_BEFORE, 1, ticknow);
}
need_wake = 1;
} else if ((void *)inp == hpts->p_inp) {
/*
* We can't allow you to go into the same slot we
* are in. We must put you out.
*/
inp->inp_hptsslot = hpts->p_nxt_slot;
} else
inp->inp_hptsslot = hpts->p_cur_slot;
hpts_sane_pace_insert(hpts, inp, &hpts->p_hptss[inp->inp_hptsslot], line, noref);
inp->inp_hpts_request = 0;
if (logging_on) {
tcp_hpts_log_it(hpts, inp, HPTSLOG_IMMEDIATE, 0, 0);
}
if (need_wake) {
/*
* Activate the hpts if it is sleeping and its
* timeout is not 1.
*/
if (logging_on) {
tcp_hpts_log_it(hpts, inp, HPTSLOG_WAKEUP_HPTS, 0, ticknow);
}
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);
}
static void
tcp_hpts_insert_locked(struct tcp_hpts_entry *hpts, struct inpcb *inp, uint32_t slot, uint32_t cts, int32_t line,
struct hpts_diag *diag, int32_t noref)
{
int32_t need_new_to = 0;
int32_t need_wakeup = 0;
uint32_t largest_slot;
uint32_t ticknow = 0;
uint32_t slot_calc;
HPTS_MTX_ASSERT(hpts);
if (diag) {
memset(diag, 0, sizeof(struct hpts_diag));
diag->p_hpts_active = hpts->p_hpts_active;
diag->p_nxt_slot = hpts->p_nxt_slot;
diag->p_cur_slot = hpts->p_cur_slot;
diag->slot_req = slot;
}
if ((inp->inp_in_hpts == 0) || noref) {
inp->inp_hpts_request = slot;
if (slot == 0) {
/* Immediate */
tcp_queue_to_hpts_immediate_locked(inp, hpts, line, noref);
return;
}
if (hpts->p_hpts_active) {
/*
* Its slot - 1 since nxt_slot is the next tick that
* will go off since the hpts is awake
*/
if (logging_on) {
tcp_hpts_log_it(hpts, inp, HPTSLOG_INSERT_NORMAL, slot, 0);
}
/*
* We want to make sure that we don't place a inp in
* the range of p_cur_slot <-> p_nxt_slot. If we
* take from p_nxt_slot to the end, plus p_cur_slot
* and then take away 2, we will know how many is
* the max slots we can use.
*/
if (hpts->p_nxt_slot > hpts->p_cur_slot) {
/*
* Non-wrap case nxt_slot <-> cur_slot we
* don't want to land in. So the diff gives
* us what is taken away from the number of
* slots.
*/
largest_slot = NUM_OF_HPTSI_SLOTS - (hpts->p_nxt_slot - hpts->p_cur_slot);
} else if (hpts->p_nxt_slot == hpts->p_cur_slot) {
largest_slot = NUM_OF_HPTSI_SLOTS - 2;
} else {
/*
* Wrap case so the diff gives us the number
* of slots that we can land in.
*/
largest_slot = hpts->p_cur_slot - hpts->p_nxt_slot;
}
/*
* We take away two so we never have a problem (20
* usec's) out of 1024000 usecs
*/
largest_slot -= 2;
if (inp->inp_hpts_request > largest_slot) {
/*
* Restrict max jump of slots and remember
* leftover
*/
slot = largest_slot;
inp->inp_hpts_request -= largest_slot;
} else {
/* This one will run when we hit it */
inp->inp_hpts_request = 0;
}
if (hpts->p_nxt_slot == hpts->p_cur_slot)
slot_calc = (hpts->p_nxt_slot + slot) % NUM_OF_HPTSI_SLOTS;
else
slot_calc = (hpts->p_nxt_slot + slot - 1) % NUM_OF_HPTSI_SLOTS;
if (slot_calc == hpts->p_cur_slot) {
#ifdef INVARIANTS
/* TSNH */
panic("Hpts:%p impossible slot calculation slot_calc:%u slot:%u largest:%u\n",
hpts, slot_calc, slot, largest_slot);
#endif
if (slot_calc)
slot_calc--;
else
slot_calc = NUM_OF_HPTSI_SLOTS - 1;
}
inp->inp_hptsslot = slot_calc;
if (diag) {
diag->inp_hptsslot = inp->inp_hptsslot;
}
} else {
/*
* The hpts is sleeping, 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;
uint32_t slot_now;
struct timeval tv;
ticknow = tcp_gethptstick(&tv);
slot_now = ticknow % NUM_OF_HPTSI_SLOTS;
/*
* The user wants to be inserted at (slot_now +
* slot) % NUM_OF_HPTSI_SLOTS, so lets set that up.
*/
largest_slot = NUM_OF_HPTSI_SLOTS - 2;
if (inp->inp_hpts_request > largest_slot) {
/* Adjust the residual in inp_hpts_request */
slot = largest_slot;
inp->inp_hpts_request -= largest_slot;
} else {
/* No residual it all fits */
inp->inp_hpts_request = 0;
}
inp->inp_hptsslot = (slot_now + slot) % NUM_OF_HPTSI_SLOTS;
if (diag) {
diag->slot_now = slot_now;
diag->inp_hptsslot = inp->inp_hptsslot;
diag->p_on_min_sleep = hpts->p_on_min_sleep;
}
if (logging_on) {
tcp_hpts_log_it(hpts, inp, HPTSLOG_INSERT_SLEEPER, slot, ticknow);
}
/* Now do we need to restart the hpts's timer? */
if (TSTMP_GT(ticknow, hpts->p_curtick))
have_slept = ticknow - hpts->p_curtick;
else
have_slept = 0;
if (have_slept < hpts->p_hpts_sleep_time) {
/* This should be what happens */
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;
diag->hpts_sleep_time = hpts->p_hpts_sleep_time;
}
if ((hpts->p_on_min_sleep == 0) && (yet_to_sleep > slot)) {
/*
* We need to reschedule the hptss time-out.
*/
hpts->p_hpts_sleep_time = slot;
need_new_to = slot * HPTS_TICKS_PER_USEC;
}
}
hpts_sane_pace_insert(hpts, inp, &hpts->p_hptss[inp->inp_hptsslot], line, noref);
if (logging_on) {
tcp_hpts_log_it(hpts, inp, HPTSLOG_INSERTED, slot, ticknow);
}
/*
* 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) {
if (logging_on) {
tcp_hpts_log_it(hpts, inp, HPTSLOG_RESCHEDULE, 1, 0);
}
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, cts;
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);
if (in_ts_percision)
microuptime(&tv);
else
getmicrouptime(&tv);
cts = tcp_tv_to_usectick(&tv);
tcp_hpts_insert_locked(hpts, inp, slot, cts, line, diag, 0);
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.
*/
if (logging_on) {
tcp_hpts_log_it(hpts, inp, HPTSLOG_WAKEUP_INPUT, 0, 0);
}
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);
}
void
tcp_queue_pkt_to_input(struct tcpcb *tp, struct mbuf *m, struct tcphdr *th,
int32_t tlen, int32_t drop_hdrlen, uint8_t iptos)
{
/* Setup packet for input first */
INP_WLOCK_ASSERT(tp->t_inpcb);
m->m_pkthdr.pace_thoff = (uint16_t) ((caddr_t)th - mtod(m, caddr_t));
m->m_pkthdr.pace_tlen = (uint16_t) tlen;
m->m_pkthdr.pace_drphdrlen = drop_hdrlen;
m->m_pkthdr.pace_tos = iptos;
m->m_pkthdr.pace_lock = (curthread->td_epochnest != 0);
if (tp->t_in_pkt == NULL) {
tp->t_in_pkt = m;
tp->t_tail_pkt = m;
} else {
tp->t_tail_pkt->m_nextpkt = m;
tp->t_tail_pkt = m;
}
}
int32_t
__tcp_queue_to_input(struct tcpcb *tp, struct mbuf *m, struct tcphdr *th,
int32_t tlen, int32_t drop_hdrlen, uint8_t iptos, int32_t line){
struct tcp_hpts_entry *hpts;
int32_t ret;
tcp_queue_pkt_to_input(tp, m, th, tlen, drop_hdrlen, iptos);
hpts = tcp_input_lock(tp->t_inpcb);
ret = __tcp_queue_to_input_locked(tp->t_inpcb, 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){
uint16_t cpuid;
/*
* 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) {
cpuid = inp->inp_flowid % mp_ncpus;
return (cpuid);
}
cpuid = hpts_random_cpu(inp);
return (cpuid);
#endif
}
/*
* 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 hptss 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 mbuf *m, *n;
struct tcpcb *tp;
struct inpcb *inp;
uint16_t drop_reason;
int16_t set_cpu;
uint32_t did_prefetch = 0;
int32_t ti_locked = TI_UNLOCKED;
struct epoch_tracker et;
HPTS_MTX_ASSERT(hpts);
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);
CURVNET_SET(inp->inp_vnet);
if (drop_reason) {
INP_INFO_RLOCK_ET(&V_tcbinfo, et);
ti_locked = TI_RLOCKED;
} else {
ti_locked = TI_UNLOCKED;
}
INP_WLOCK(inp);
if ((inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) ||
(inp->inp_flags2 & INP_FREED)) {
out:
hpts->p_inp = NULL;
if (ti_locked == TI_RLOCKED) {
INP_INFO_RUNLOCK_ET(&V_tcbinfo, et);
}
if (in_pcbrele_wlocked(inp) == 0) {
INP_WUNLOCK(inp);
}
ti_locked = TI_UNLOCKED;
CURVNET_RESTORE();
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 */
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;
}
tp = tcp_drop(tp, drop_reason);
INP_INFO_RUNLOCK_ET(&V_tcbinfo, et);
if (tp == NULL) {
INP_WLOCK(inp);
}
if (in_pcbrele_wlocked(inp) == 0)
INP_WUNLOCK(inp);
CURVNET_RESTORE();
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);
}
m = tp->t_in_pkt;
n = NULL;
if (m != NULL &&
(m->m_pkthdr.pace_lock == TI_RLOCKED ||
tp->t_state != TCPS_ESTABLISHED)) {
ti_locked = TI_RLOCKED;
INP_INFO_RLOCK_ET(&V_tcbinfo, et);
m = tp->t_in_pkt;
}
if (in_newts_every_tcb) {
if (in_ts_percision)
microuptime(tv);
else
getmicrouptime(tv);
}
if (tp->t_fb_ptr != NULL) {
kern_prefetch(tp->t_fb_ptr, &did_prefetch);
did_prefetch = 1;
}
/* Any input work to do, if so do it first */
if ((m != NULL) && (m == tp->t_in_pkt)) {
struct tcphdr *th;
int32_t tlen, drop_hdrlen, nxt_pkt;
uint8_t iptos;
n = m->m_nextpkt;
tp->t_in_pkt = tp->t_tail_pkt = NULL;
while (m) {
th = (struct tcphdr *)(mtod(m, caddr_t)+m->m_pkthdr.pace_thoff);
tlen = m->m_pkthdr.pace_tlen;
drop_hdrlen = m->m_pkthdr.pace_drphdrlen;
iptos = m->m_pkthdr.pace_tos;
m->m_nextpkt = NULL;
if (n)
nxt_pkt = 1;
else
nxt_pkt = 0;
inp->inp_input_calls = 1;
if (tp->t_fb->tfb_tcp_hpts_do_segment) {
/* Use the hpts specific do_segment */
(*tp->t_fb->tfb_tcp_hpts_do_segment) (m, th, inp->inp_socket,
tp, drop_hdrlen,
tlen, iptos, nxt_pkt, tv);
} else {
/* Use the default do_segment */
(*tp->t_fb->tfb_tcp_do_segment) (m, th, inp->inp_socket,
tp, drop_hdrlen,
tlen, iptos);
}
if (ti_locked == TI_RLOCKED)
INP_INFO_RUNLOCK_ET(&V_tcbinfo, et);
/*
* Do segment returns unlocked we need the
* lock again but we also need some kasserts
* here.
*/
INP_INFO_UNLOCK_ASSERT(&V_tcbinfo);
INP_UNLOCK_ASSERT(inp);
m = n;
if (m)
n = m->m_nextpkt;
if (m != NULL &&
m->m_pkthdr.pace_lock == TI_RLOCKED) {
INP_INFO_RLOCK_ET(&V_tcbinfo, et);
ti_locked = TI_RLOCKED;
} else
ti_locked = TI_UNLOCKED;
INP_WLOCK(inp);
/*
* Since we have an opening here we must
* re-check if the tcb went away while we
* were getting the lock(s).
*/
if ((inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) ||
(inp->inp_flags2 & INP_FREED)) {
while (m) {
m_freem(m);
m = n;
if (m)
n = m->m_nextpkt;
}
goto out;
}
/*
* Now that we hold the INP lock, check if
* we need to upgrade our lock.
*/
if (ti_locked == TI_UNLOCKED &&
(tp->t_state != TCPS_ESTABLISHED)) {
ti_locked = TI_RLOCKED;
INP_INFO_RLOCK_ET(&V_tcbinfo, et);
}
} /** end while(m) */
} /** end if ((m != NULL) && (m == tp->t_in_pkt)) */
if (in_pcbrele_wlocked(inp) == 0)
INP_WUNLOCK(inp);
if (ti_locked == TI_RLOCKED)
INP_INFO_RUNLOCK_ET(&V_tcbinfo, et);
INP_INFO_UNLOCK_ASSERT(&V_tcbinfo);
INP_UNLOCK_ASSERT(inp);
ti_locked = TI_UNLOCKED;
mtx_lock(&hpts->p_mtx);
hpts->p_inp = NULL;
CURVNET_RESTORE();
}
}
static int
tcp_hpts_est_run(struct tcp_hpts_entry *hpts)
{
int32_t ticks_to_run;
if (hpts->p_prevtick && (SEQ_GT(hpts->p_curtick, hpts->p_prevtick))) {
ticks_to_run = hpts->p_curtick - hpts->p_prevtick;
if (ticks_to_run >= (NUM_OF_HPTSI_SLOTS - 1)) {
ticks_to_run = NUM_OF_HPTSI_SLOTS - 2;
}
} else {
if (hpts->p_prevtick == hpts->p_curtick) {
/* This happens when we get woken up right away */
return (-1);
}
ticks_to_run = 1;
}
/* Set in where we will be when we catch up */
hpts->p_nxt_slot = (hpts->p_cur_slot + ticks_to_run) % NUM_OF_HPTSI_SLOTS;
if (hpts->p_nxt_slot == hpts->p_cur_slot) {
panic("Impossible math -- hpts:%p p_nxt_slot:%d p_cur_slot:%d ticks_to_run:%d",
hpts, hpts->p_nxt_slot, hpts->p_cur_slot, ticks_to_run);
}
return (ticks_to_run);
}
static void
tcp_hptsi(struct tcp_hpts_entry *hpts, struct timeval *ctick)
{
struct tcpcb *tp;
struct inpcb *inp = NULL, *ninp;
struct timeval tv;
int32_t ticks_to_run, i, error, tick_now, interum_tick;
int32_t paced_cnt = 0;
int32_t did_prefetch = 0;
int32_t prefetch_ninp = 0;
int32_t prefetch_tp = 0;
uint32_t cts;
int16_t set_cpu;
HPTS_MTX_ASSERT(hpts);
hpts->p_curtick = tcp_tv_to_hptstick(ctick);
cts = tcp_tv_to_usectick(ctick);
memcpy(&tv, ctick, sizeof(struct timeval));
hpts->p_cur_slot = hpts_tick(hpts, 1);
/* Figure out if we had missed ticks */
again:
HPTS_MTX_ASSERT(hpts);
ticks_to_run = tcp_hpts_est_run(hpts);
if (!TAILQ_EMPTY(&hpts->p_input)) {
tcp_input_data(hpts, &tv);
}
#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);
/* Reset the ticks to run and time if we need too */
interum_tick = tcp_gethptstick(&tv);
if (interum_tick != hpts->p_curtick) {
/* Save off the new time we execute to */
*ctick = tv;
hpts->p_curtick = interum_tick;
cts = tcp_tv_to_usectick(&tv);
hpts->p_cur_slot = hpts_tick(hpts, 1);
ticks_to_run = tcp_hpts_est_run(hpts);
}
if (ticks_to_run == -1) {
goto no_run;
}
if (logging_on) {
tcp_hpts_log_it(hpts, inp, HPTSLOG_SETTORUN, ticks_to_run, 0);
}
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
*/
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_cur_slot])) != NULL) {
/* For debugging */
if (logging_on) {
tcp_hpts_log_it(hpts, inp, HPTSLOG_HPTSI, ticks_to_run, i);
}
hpts->p_inp = inp;
paced_cnt++;
if (hpts->p_cur_slot != inp->inp_hptsslot) {
panic("Hpts:%p inp:%p slot mis-aligned %u vs %u",
hpts, inp, hpts->p_cur_slot, inp->inp_hptsslot);
}
/* 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_cur_slot], 0);
if ((ninp = TAILQ_FIRST(&hpts->p_hptss[hpts->p_cur_slot])) != 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 on it. Push him back
* on the wheel.
*/
int32_t remaining_slots;
remaining_slots = ticks_to_run - (i + 1);
if (inp->inp_hpts_request > remaining_slots) {
/*
* Keep INVARIANTS happy by clearing
* the flag
*/
tcp_hpts_insert_locked(hpts, inp, inp->inp_hpts_request, cts, __LINE__, NULL, 1);
hpts->p_inp = NULL;
continue;
}
inp->inp_hpts_request = 0;
}
/*
* 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);
if (logging_on)
tcp_hpts_log_it(hpts, hpts->p_inp, HPTSLOG_INP_DONE, 0, 1);
hpts->p_inp = NULL;
continue;
}
if (inp->inp_flags & (INP_TIMEWAIT | INP_DROPPED)) {
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);
if (logging_on)
tcp_hpts_log_it(hpts, hpts->p_inp, HPTSLOG_INP_DONE, 0, 3);
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);
}
if (out_newts_every_tcb) {
struct timeval sv;
if (out_ts_percision)
microuptime(&sv);
else
getmicrouptime(&sv);
cts = tcp_tv_to_usectick(&sv);
}
CURVNET_SET(inp->inp_vnet);
/*
* 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;
}
inp->inp_hpts_calls = 1;
if (tp->t_fb->tfb_tcp_output_wtime != NULL) {
error = (*tp->t_fb->tfb_tcp_output_wtime) (tp, &tv);
} else {
error = tp->t_fb->tfb_tcp_output(tp);
}
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);
INP_UNLOCK_ASSERT(inp);
CURVNET_RESTORE();
#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 (logging_on)
tcp_hpts_log_it(hpts, hpts->p_inp, HPTSLOG_INP_DONE, 0, 4);
hpts->p_inp = NULL;
}
HPTS_MTX_ASSERT(hpts);
hpts->p_inp = NULL;
hpts->p_cur_slot++;
if (hpts->p_cur_slot >= NUM_OF_HPTSI_SLOTS) {
hpts->p_cur_slot = 0;
}
}
no_one:
HPTS_MTX_ASSERT(hpts);
hpts->p_prevtick = hpts->p_curtick;
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).
*/
/* Re-run any input that may be there */
(void)tcp_gethptstick(&tv);
if (!TAILQ_EMPTY(&hpts->p_input)) {
tcp_input_data(hpts, &tv);
}
#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
tick_now = tcp_gethptstick(&tv);
if (SEQ_GT(tick_now, hpts->p_prevtick)) {
struct timeval res;
/* Did we really spend a full tick or more in here? */
timersub(&tv, ctick, &res);
if (res.tv_sec || (res.tv_usec >= HPTS_TICKS_PER_USEC)) {
counter_u64_add(hpts_loops, 1);
if (logging_on) {
tcp_hpts_log_it(hpts, inp, HPTSLOG_TOLONG, (uint32_t) res.tv_usec, tick_now);
}
*ctick = res;
hpts->p_curtick = tick_now;
goto again;
}
}
no_run:
{
uint32_t t = 0, i, fnd = 0;
if (hpts->p_on_queue_cnt) {
/*
* Find next slot that is occupied and use that to
* be the sleep time.
*/
for (i = 1, t = hpts->p_nxt_slot; 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 = i;
} else {
counter_u64_add(back_tosleep, 1);
#ifdef INVARIANTS
panic("Hpts:%p cnt:%d but non found", hpts, hpts->p_on_queue_cnt);
#endif
hpts->p_on_queue_cnt = 0;
goto non_found;
}
t++;
} else {
/* No one on the wheel sleep for all but 2 slots */
non_found:
if (hpts_sleep_max == 0)
hpts_sleep_max = 1;
hpts->p_hpts_sleep_time = min((NUM_OF_HPTSI_SLOTS - 2), hpts_sleep_max);
t = 0;
}
if (logging_on) {
tcp_hpts_log_it(hpts, inp, HPTSLOG_SLEEPSET, t, (hpts->p_hpts_sleep_time * HPTS_TICKS_PER_USEC));
}
}
}
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 timeval tv;
sbintime_t sb;
hpts = (struct tcp_hpts_entry *)ctx;
mtx_lock(&hpts->p_mtx);
if (hpts->p_direct_wake) {
/* Signaled by input */
if (logging_on)
tcp_hpts_log_it(hpts, NULL, HPTSLOG_AWAKE, 1, 1);
callout_stop(&hpts->co);
} else {
/* Timed out */
if (callout_pending(&hpts->co) ||
!callout_active(&hpts->co)) {
if (logging_on)
tcp_hpts_log_it(hpts, NULL, HPTSLOG_AWAKE, 2, 2);
mtx_unlock(&hpts->p_mtx);
return;
}
callout_deactivate(&hpts->co);
if (logging_on)
tcp_hpts_log_it(hpts, NULL, HPTSLOG_AWAKE, 3, 3);
}
hpts->p_hpts_active = 1;
(void)tcp_gethptstick(&tv);
tcp_hptsi(hpts, &tv);
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)) {
tv.tv_usec = tcp_min_hptsi_time;
hpts->p_on_min_sleep = 1;
} else {
/* Clear the min sleep flag */
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;
char unit[16];
uint32_t ncpus = mp_ncpus ? mp_ncpus : MAXCPU;
tcp_pace.rp_proc = NULL;
tcp_pace.rp_num_hptss = ncpus;
hpts_loops = counter_u64_alloc(M_WAITOK);
back_tosleep = 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_UINT(&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 slot is if active");
SYSCTL_ADD_UINT(&hpts->hpts_ctx,
SYSCTL_CHILDREN(hpts->hpts_root),
OID_AUTO, "curtick", CTLFLAG_RD,
&hpts->p_curtick, 0,
"What the current tick on if active");
SYSCTL_ADD_UINT(&hpts->hpts_ctx,
SYSCTL_CHILDREN(hpts->hpts_root),
OID_AUTO, "logsize", CTLFLAG_RD,
&hpts->p_logsize, 0,
"Hpts logging buffer size");
hpts->p_hpts_sleep_time = NUM_OF_HPTSI_SLOTS - 2;
hpts->p_num = i;
hpts->p_prevtick = hpts->p_curtick = tcp_gethptstick(&tv);
hpts->p_prevtick -= 1;
hpts->p_prevtick %= NUM_OF_HPTSI_SLOTS;
hpts->p_cpu = 0xffff;
hpts->p_nxt_slot = 1;
hpts->p_logsize = tcp_hpts_logging_size;
if (hpts->p_logsize) {
sz = (sizeof(struct hpts_log) * hpts->p_logsize);
hpts->p_log = malloc(sz, M_TCPHPTS, M_WAITOK | M_ZERO);
}
callout_init(&hpts->co, 1);
}
/*
* 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) {
if (intr_event_bind(hpts->ie, i) == 0)
bound++;
}
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));
}
}
printf("TCP Hpts created %d swi interrupt thread and bound %d\n",
created, bound);
return;
}
SYSINIT(tcphptsi, SI_SUB_KTHREAD_IDLE, SI_ORDER_ANY, tcp_init_hptsi, NULL);
MODULE_VERSION(tcphpts, 1);
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