kernel = Fix tsleep(), remove MAILBOX signals, change signalset locks for LWPs
[dragonfly.git] / sys / kern / lwkt_ipiq.c
CommitLineData
3b6b7bd1 1/*
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2 * Copyright (c) 2003,2004 The DragonFly Project. All rights reserved.
3 *
4 * This code is derived from software contributed to The DragonFly Project
5 * by Matthew Dillon <dillon@backplane.com>
6 *
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7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
8c10bfcf 10 *
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11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
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14 * notice, this list of conditions and the following disclaimer in
15 * the documentation and/or other materials provided with the
16 * distribution.
17 * 3. Neither the name of The DragonFly Project nor the names of its
18 * contributors may be used to endorse or promote products derived
19 * from this software without specific, prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
25 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
26 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
28 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
29 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
30 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
31 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
3b6b7bd1 32 * SUCH DAMAGE.
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33 */
34
35/*
36 * This module implements IPI message queueing and the MI portion of IPI
37 * message processing.
38 */
39
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40#include "opt_ddb.h"
41
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42#include <sys/param.h>
43#include <sys/systm.h>
44#include <sys/kernel.h>
45#include <sys/proc.h>
46#include <sys/rtprio.h>
47#include <sys/queue.h>
48#include <sys/thread2.h>
49#include <sys/sysctl.h>
ac72c7f4 50#include <sys/ktr.h>
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51#include <sys/kthread.h>
52#include <machine/cpu.h>
53#include <sys/lock.h>
54#include <sys/caps.h>
55
56#include <vm/vm.h>
57#include <vm/vm_param.h>
58#include <vm/vm_kern.h>
59#include <vm/vm_object.h>
60#include <vm/vm_page.h>
61#include <vm/vm_map.h>
62#include <vm/vm_pager.h>
63#include <vm/vm_extern.h>
64#include <vm/vm_zone.h>
65
66#include <machine/stdarg.h>
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67#include <machine/smp.h>
68#include <machine/atomic.h>
69
3b6b7bd1 70#ifdef SMP
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71static __int64_t ipiq_count; /* total calls to lwkt_send_ipiq*() */
72static __int64_t ipiq_fifofull; /* number of fifo full conditions detected */
73static __int64_t ipiq_avoided; /* interlock with target avoids cpu ipi */
74static __int64_t ipiq_passive; /* passive IPI messages */
75static __int64_t ipiq_cscount; /* number of cpu synchronizations */
d5b2d319 76static int ipiq_debug; /* set to 1 for debug */
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77#ifdef PANIC_DEBUG
78static int panic_ipiq_cpu = -1;
79static int panic_ipiq_count = 100;
80#endif
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81#endif
82
3b6b7bd1 83#ifdef SMP
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84SYSCTL_QUAD(_lwkt, OID_AUTO, ipiq_count, CTLFLAG_RW, &ipiq_count, 0,
85 "Number of IPI's sent");
86SYSCTL_QUAD(_lwkt, OID_AUTO, ipiq_fifofull, CTLFLAG_RW, &ipiq_fifofull, 0,
87 "Number of fifo full conditions detected");
88SYSCTL_QUAD(_lwkt, OID_AUTO, ipiq_avoided, CTLFLAG_RW, &ipiq_avoided, 0,
89 "Number of IPI's avoided by interlock with target cpu");
90SYSCTL_QUAD(_lwkt, OID_AUTO, ipiq_passive, CTLFLAG_RW, &ipiq_passive, 0,
91 "Number of passive IPI messages sent");
92SYSCTL_QUAD(_lwkt, OID_AUTO, ipiq_cscount, CTLFLAG_RW, &ipiq_cscount, 0,
93 "Number of cpu synchronizations");
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94SYSCTL_INT(_lwkt, OID_AUTO, ipiq_debug, CTLFLAG_RW, &ipiq_debug, 0,
95 "");
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96#ifdef PANIC_DEBUG
97SYSCTL_INT(_lwkt, OID_AUTO, panic_ipiq_cpu, CTLFLAG_RW, &panic_ipiq_cpu, 0, "");
98SYSCTL_INT(_lwkt, OID_AUTO, panic_ipiq_count, CTLFLAG_RW, &panic_ipiq_count, 0, "");
99#endif
3b6b7bd1 100
a7adb95a 101#define IPIQ_STRING "func=%p arg1=%p arg2=%d scpu=%d dcpu=%d"
5118bbc4 102#define IPIQ_ARG_SIZE (sizeof(void *) * 2 + sizeof(int) * 3)
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103
104#if !defined(KTR_IPIQ)
105#define KTR_IPIQ KTR_ALL
3b6b7bd1 106#endif
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107KTR_INFO_MASTER(ipiq);
108KTR_INFO(KTR_IPIQ, ipiq, send_norm, 0, IPIQ_STRING, IPIQ_ARG_SIZE);
109KTR_INFO(KTR_IPIQ, ipiq, send_pasv, 1, IPIQ_STRING, IPIQ_ARG_SIZE);
110KTR_INFO(KTR_IPIQ, ipiq, send_nbio, 2, IPIQ_STRING, IPIQ_ARG_SIZE);
111KTR_INFO(KTR_IPIQ, ipiq, send_fail, 3, IPIQ_STRING, IPIQ_ARG_SIZE);
112KTR_INFO(KTR_IPIQ, ipiq, receive, 4, IPIQ_STRING, IPIQ_ARG_SIZE);
d7ed9e5e 113KTR_INFO(KTR_IPIQ, ipiq, sync_start, 5, "cpumask=%08x", sizeof(cpumask_t));
d5b2d319 114KTR_INFO(KTR_IPIQ, ipiq, sync_end, 6, "cpumask=%08x", sizeof(cpumask_t));
866b61fb 115KTR_INFO(KTR_IPIQ, ipiq, cpu_send, 7, IPIQ_STRING, IPIQ_ARG_SIZE);
c92e86f1 116KTR_INFO(KTR_IPIQ, ipiq, send_end, 8, IPIQ_STRING, IPIQ_ARG_SIZE);
ac72c7f4 117
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118#define logipiq(name, func, arg1, arg2, sgd, dgd) \
119 KTR_LOG(ipiq_ ## name, func, arg1, arg2, sgd->gd_cpuid, dgd->gd_cpuid)
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120#define logipiq2(name, arg) \
121 KTR_LOG(ipiq_ ## name, arg)
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122
123#endif /* SMP */
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124
125#ifdef SMP
126
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127static int lwkt_process_ipiq_core(globaldata_t sgd, lwkt_ipiq_t ip,
128 struct intrframe *frame);
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129static void lwkt_cpusync_remote1(lwkt_cpusync_t cs);
130static void lwkt_cpusync_remote2(lwkt_cpusync_t cs);
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131
132/*
133 * Send a function execution request to another cpu. The request is queued
134 * on the cpu<->cpu ipiq matrix. Each cpu owns a unique ipiq FIFO for every
135 * possible target cpu. The FIFO can be written.
136 *
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137 * If the FIFO fills up we have to enable interrupts to avoid an APIC
138 * deadlock and process pending IPIQs while waiting for it to empty.
139 * Otherwise we may soft-deadlock with another cpu whos FIFO is also full.
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140 *
141 * We can safely bump gd_intr_nesting_level because our crit_exit() at the
142 * end will take care of any pending interrupts.
143 *
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144 * The actual hardware IPI is avoided if the target cpu is already processing
145 * the queue from a prior IPI. It is possible to pipeline IPI messages
146 * very quickly between cpus due to the FIFO hysteresis.
147 *
148 * Need not be called from a critical section.
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149 */
150int
b8a98473 151lwkt_send_ipiq3(globaldata_t target, ipifunc3_t func, void *arg1, int arg2)
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152{
153 lwkt_ipiq_t ip;
154 int windex;
155 struct globaldata *gd = mycpu;
156
a7adb95a 157 logipiq(send_norm, func, arg1, arg2, gd, target);
ac72c7f4 158
3b6b7bd1 159 if (target == gd) {
b8a98473 160 func(arg1, arg2, NULL);
c92e86f1 161 logipiq(send_end, func, arg1, arg2, gd, target);
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162 return(0);
163 }
164 crit_enter();
165 ++gd->gd_intr_nesting_level;
166#ifdef INVARIANTS
167 if (gd->gd_intr_nesting_level > 20)
168 panic("lwkt_send_ipiq: TOO HEAVILY NESTED!");
169#endif
f9235b6d 170 KKASSERT(curthread->td_critcount);
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171 ++ipiq_count;
172 ip = &gd->gd_ipiq[target->gd_cpuid];
173
174 /*
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175 * Do not allow the FIFO to become full. Interrupts must be physically
176 * enabled while we liveloop to avoid deadlocking the APIC.
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177 *
178 * The target ipiq may have gotten filled up due to passive IPIs and thus
179 * not be aware that its queue is too full, so be sure to issue an
180 * ipiq interrupt to the target cpu.
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181 */
182 if (ip->ip_windex - ip->ip_rindex > MAXCPUFIFO / 2) {
46d4e165 183#if defined(__i386__)
4c9f5a7f 184 unsigned int eflags = read_eflags();
b2b3ffcd 185#elif defined(__x86_64__)
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JG
186 unsigned long rflags = read_rflags();
187#endif
4c9f5a7f 188
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189 cpu_enable_intr();
190 ++ipiq_fifofull;
cfaeae2a 191 DEBUG_PUSH_INFO("send_ipiq3");
4c9f5a7f 192 while (ip->ip_windex - ip->ip_rindex > MAXCPUFIFO / 4) {
b12defdc 193 if (atomic_poll_acquire_int(&target->gd_npoll)) {
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194 logipiq(cpu_send, func, arg1, arg2, gd, target);
195 cpu_send_ipiq(target->gd_cpuid);
196 }
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197 KKASSERT(ip->ip_windex - ip->ip_rindex != MAXCPUFIFO - 1);
198 lwkt_process_ipiq();
da0b0e8b 199 cpu_pause();
4c9f5a7f 200 }
cfaeae2a 201 DEBUG_POP_INFO();
46d4e165 202#if defined(__i386__)
4c9f5a7f 203 write_eflags(eflags);
b2b3ffcd 204#elif defined(__x86_64__)
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205 write_rflags(rflags);
206#endif
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207 }
208
209 /*
210 * Queue the new message
3b6b7bd1 211 */
3b6b7bd1 212 windex = ip->ip_windex & MAXCPUFIFO_MASK;
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213 ip->ip_info[windex].func = func;
214 ip->ip_info[windex].arg1 = arg1;
215 ip->ip_info[windex].arg2 = arg2;
35238fa5 216 cpu_sfence();
3b6b7bd1 217 ++ip->ip_windex;
b12defdc 218 atomic_set_cpumask(&target->gd_ipimask, gd->gd_cpumask);
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219
220 /*
221 * signal the target cpu that there is work pending.
222 */
b12defdc 223 if (atomic_poll_acquire_int(&target->gd_npoll)) {
866b61fb 224 logipiq(cpu_send, func, arg1, arg2, gd, target);
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225 cpu_send_ipiq(target->gd_cpuid);
226 } else {
da0b0e8b 227 ++ipiq_avoided;
4c9f5a7f 228 }
da0b0e8b 229 --gd->gd_intr_nesting_level;
4c9f5a7f 230 crit_exit();
c92e86f1 231 logipiq(send_end, func, arg1, arg2, gd, target);
da0b0e8b 232
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233 return(ip->ip_windex);
234}
235
236/*
237 * Similar to lwkt_send_ipiq() but this function does not actually initiate
238 * the IPI to the target cpu unless the FIFO has become too full, so it is
239 * very fast.
240 *
241 * This function is used for non-critical IPI messages, such as memory
242 * deallocations. The queue will typically be flushed by the target cpu at
243 * the next clock interrupt.
244 *
245 * Need not be called from a critical section.
246 */
247int
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248lwkt_send_ipiq3_passive(globaldata_t target, ipifunc3_t func,
249 void *arg1, int arg2)
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250{
251 lwkt_ipiq_t ip;
252 int windex;
253 struct globaldata *gd = mycpu;
254
255 KKASSERT(target != gd);
256 crit_enter();
257 ++gd->gd_intr_nesting_level;
da0b0e8b 258 logipiq(send_pasv, func, arg1, arg2, gd, target);
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259#ifdef INVARIANTS
260 if (gd->gd_intr_nesting_level > 20)
261 panic("lwkt_send_ipiq: TOO HEAVILY NESTED!");
262#endif
f9235b6d 263 KKASSERT(curthread->td_critcount);
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264 ++ipiq_count;
265 ++ipiq_passive;
266 ip = &gd->gd_ipiq[target->gd_cpuid];
267
268 /*
269 * Do not allow the FIFO to become full. Interrupts must be physically
270 * enabled while we liveloop to avoid deadlocking the APIC.
271 */
3b6b7bd1 272 if (ip->ip_windex - ip->ip_rindex > MAXCPUFIFO / 2) {
46d4e165 273#if defined(__i386__)
3b6b7bd1 274 unsigned int eflags = read_eflags();
b2b3ffcd 275#elif defined(__x86_64__)
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JG
276 unsigned long rflags = read_rflags();
277#endif
4c9f5a7f 278
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279 cpu_enable_intr();
280 ++ipiq_fifofull;
cfaeae2a 281 DEBUG_PUSH_INFO("send_ipiq3_passive");
3b6b7bd1 282 while (ip->ip_windex - ip->ip_rindex > MAXCPUFIFO / 4) {
b12defdc 283 if (atomic_poll_acquire_int(&target->gd_npoll)) {
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284 logipiq(cpu_send, func, arg1, arg2, gd, target);
285 cpu_send_ipiq(target->gd_cpuid);
286 }
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287 KKASSERT(ip->ip_windex - ip->ip_rindex != MAXCPUFIFO - 1);
288 lwkt_process_ipiq();
da0b0e8b 289 cpu_pause();
3b6b7bd1 290 }
cfaeae2a 291 DEBUG_POP_INFO();
46d4e165 292#if defined(__i386__)
3b6b7bd1 293 write_eflags(eflags);
b2b3ffcd 294#elif defined(__x86_64__)
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295 write_rflags(rflags);
296#endif
3b6b7bd1 297 }
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298
299 /*
300 * Queue the new message
301 */
302 windex = ip->ip_windex & MAXCPUFIFO_MASK;
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303 ip->ip_info[windex].func = func;
304 ip->ip_info[windex].arg1 = arg1;
305 ip->ip_info[windex].arg2 = arg2;
35238fa5 306 cpu_sfence();
4c9f5a7f 307 ++ip->ip_windex;
b12defdc 308 atomic_set_cpumask(&target->gd_ipimask, gd->gd_cpumask);
3b6b7bd1 309 --gd->gd_intr_nesting_level;
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310
311 /*
312 * Do not signal the target cpu, it will pick up the IPI when it next
313 * polls (typically on the next tick).
314 */
3b6b7bd1 315 crit_exit();
c92e86f1 316 logipiq(send_end, func, arg1, arg2, gd, target);
da0b0e8b 317
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318 return(ip->ip_windex);
319}
320
41a01a4d 321/*
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322 * Send an IPI request without blocking, return 0 on success, ENOENT on
323 * failure. The actual queueing of the hardware IPI may still force us
324 * to spin and process incoming IPIs but that will eventually go away
325 * when we've gotten rid of the other general IPIs.
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326 */
327int
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328lwkt_send_ipiq3_nowait(globaldata_t target, ipifunc3_t func,
329 void *arg1, int arg2)
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330{
331 lwkt_ipiq_t ip;
332 int windex;
333 struct globaldata *gd = mycpu;
334
a7adb95a 335 logipiq(send_nbio, func, arg1, arg2, gd, target);
f9235b6d 336 KKASSERT(curthread->td_critcount);
41a01a4d 337 if (target == gd) {
b8a98473 338 func(arg1, arg2, NULL);
c92e86f1 339 logipiq(send_end, func, arg1, arg2, gd, target);
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340 return(0);
341 }
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342 crit_enter();
343 ++gd->gd_intr_nesting_level;
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344 ++ipiq_count;
345 ip = &gd->gd_ipiq[target->gd_cpuid];
346
ac72c7f4 347 if (ip->ip_windex - ip->ip_rindex >= MAXCPUFIFO * 2 / 3) {
a7adb95a 348 logipiq(send_fail, func, arg1, arg2, gd, target);
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349 --gd->gd_intr_nesting_level;
350 crit_exit();
41a01a4d 351 return(ENOENT);
ac72c7f4 352 }
41a01a4d 353 windex = ip->ip_windex & MAXCPUFIFO_MASK;
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354 ip->ip_info[windex].func = func;
355 ip->ip_info[windex].arg1 = arg1;
356 ip->ip_info[windex].arg2 = arg2;
35238fa5 357 cpu_sfence();
41a01a4d 358 ++ip->ip_windex;
b12defdc 359 atomic_set_cpumask(&target->gd_ipimask, gd->gd_cpumask);
4c9f5a7f 360
41a01a4d 361 /*
4c9f5a7f 362 * This isn't a passive IPI, we still have to signal the target cpu.
41a01a4d 363 */
b12defdc 364 if (atomic_poll_acquire_int(&target->gd_npoll)) {
866b61fb 365 logipiq(cpu_send, func, arg1, arg2, gd, target);
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366 cpu_send_ipiq(target->gd_cpuid);
367 } else {
da0b0e8b 368 ++ipiq_avoided;
4c9f5a7f 369 }
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370 --gd->gd_intr_nesting_level;
371 crit_exit();
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372
373 logipiq(send_end, func, arg1, arg2, gd, target);
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374 return(0);
375}
376
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377/*
378 * deprecated, used only by fast int forwarding.
379 */
380int
b8a98473 381lwkt_send_ipiq3_bycpu(int dcpu, ipifunc3_t func, void *arg1, int arg2)
3b6b7bd1 382{
b8a98473 383 return(lwkt_send_ipiq3(globaldata_find(dcpu), func, arg1, arg2));
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384}
385
386/*
387 * Send a message to several target cpus. Typically used for scheduling.
388 * The message will not be sent to stopped cpus.
389 */
390int
da23a592 391lwkt_send_ipiq3_mask(cpumask_t mask, ipifunc3_t func, void *arg1, int arg2)
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392{
393 int cpuid;
394 int count = 0;
395
396 mask &= ~stopped_cpus;
397 while (mask) {
da23a592 398 cpuid = BSFCPUMASK(mask);
b8a98473 399 lwkt_send_ipiq3(globaldata_find(cpuid), func, arg1, arg2);
da23a592 400 mask &= ~CPUMASK(cpuid);
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401 ++count;
402 }
403 return(count);
404}
405
406/*
407 * Wait for the remote cpu to finish processing a function.
408 *
409 * YYY we have to enable interrupts and process the IPIQ while waiting
410 * for it to empty or we may deadlock with another cpu. Create a CPU_*()
411 * function to do this! YYY we really should 'block' here.
412 *
413 * MUST be called from a critical section. This routine may be called
414 * from an interrupt (for example, if an interrupt wakes a foreign thread
415 * up).
416 */
417void
418lwkt_wait_ipiq(globaldata_t target, int seq)
419{
420 lwkt_ipiq_t ip;
421 int maxc = 100000000;
422
423 if (target != mycpu) {
424 ip = &mycpu->gd_ipiq[target->gd_cpuid];
425 if ((int)(ip->ip_xindex - seq) < 0) {
46d4e165 426#if defined(__i386__)
3b6b7bd1 427 unsigned int eflags = read_eflags();
b2b3ffcd 428#elif defined(__x86_64__)
46d4e165
JG
429 unsigned long rflags = read_rflags();
430#endif
3b6b7bd1 431 cpu_enable_intr();
cfaeae2a 432 DEBUG_PUSH_INFO("wait_ipiq");
3b6b7bd1 433 while ((int)(ip->ip_xindex - seq) < 0) {
41a01a4d 434 crit_enter();
3b6b7bd1 435 lwkt_process_ipiq();
41a01a4d 436 crit_exit();
3b6b7bd1 437 if (--maxc == 0)
6ea70f76 438 kprintf("LWKT_WAIT_IPIQ WARNING! %d wait %d (%d)\n", mycpu->gd_cpuid, target->gd_cpuid, ip->ip_xindex - seq);
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439 if (maxc < -1000000)
440 panic("LWKT_WAIT_IPIQ");
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441 /*
442 * xindex may be modified by another cpu, use a load fence
443 * to ensure that the loop does not use a speculative value
444 * (which may improve performance).
445 */
446 cpu_lfence();
3b6b7bd1 447 }
cfaeae2a 448 DEBUG_POP_INFO();
46d4e165 449#if defined(__i386__)
3b6b7bd1 450 write_eflags(eflags);
b2b3ffcd 451#elif defined(__x86_64__)
46d4e165
JG
452 write_rflags(rflags);
453#endif
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454 }
455 }
456}
457
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458int
459lwkt_seq_ipiq(globaldata_t target)
460{
461 lwkt_ipiq_t ip;
462
463 ip = &mycpu->gd_ipiq[target->gd_cpuid];
464 return(ip->ip_windex);
465}
466
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467/*
468 * Called from IPI interrupt (like a fast interrupt), which has placed
469 * us in a critical section. The MP lock may or may not be held.
470 * May also be called from doreti or splz, or be reentrantly called
b12defdc 471 * indirectly through the ip_info[].func we run.
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472 *
473 * There are two versions, one where no interrupt frame is available (when
474 * called from the send code and from splz, and one where an interrupt
475 * frame is available.
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476 *
477 * When the current cpu is mastering a cpusync we do NOT internally loop
478 * on the cpusyncq poll. We also do not re-flag a pending ipi due to
479 * the cpusyncq poll because this can cause doreti/splz to loop internally.
480 * The cpusync master's own loop must be allowed to run to avoid a deadlock.
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481 */
482void
483lwkt_process_ipiq(void)
484{
485 globaldata_t gd = mycpu;
ac72c7f4 486 globaldata_t sgd;
3b6b7bd1 487 lwkt_ipiq_t ip;
b12defdc 488 cpumask_t mask;
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489 int n;
490
da0b0e8b 491 ++gd->gd_processing_ipiq;
3b6b7bd1 492again:
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MD
493 cpu_lfence();
494 mask = gd->gd_ipimask;
495 atomic_clear_cpumask(&gd->gd_ipimask, mask);
496 while (mask) {
497 n = BSFCPUMASK(mask);
3b6b7bd1 498 if (n != gd->gd_cpuid) {
ac72c7f4
MD
499 sgd = globaldata_find(n);
500 ip = sgd->gd_ipiq;
3b6b7bd1 501 if (ip != NULL) {
b8a98473 502 while (lwkt_process_ipiq_core(sgd, &ip[gd->gd_cpuid], NULL))
3b6b7bd1
MD
503 ;
504 }
505 }
b12defdc 506 mask &= ~CPUMASK(n);
3b6b7bd1 507 }
da0b0e8b
MD
508 if (lwkt_process_ipiq_core(gd, &gd->gd_cpusyncq, NULL)) {
509 if (gd->gd_curthread->td_cscount == 0)
510 goto again;
511 /* need_ipiq(); do not reflag */
3b6b7bd1 512 }
b12defdc
MD
513
514 /*
515 * Interlock to allow more IPI interrupts. Recheck ipimask after
516 * releasing gd_npoll.
517 */
518 if (gd->gd_ipimask)
519 goto again;
520 atomic_poll_release_int(&gd->gd_npoll);
521 cpu_mfence();
522 if (gd->gd_ipimask)
523 goto again;
da0b0e8b 524 --gd->gd_processing_ipiq;
3b6b7bd1
MD
525}
526
3b6b7bd1 527void
c7eb0589 528lwkt_process_ipiq_frame(struct intrframe *frame)
3b6b7bd1
MD
529{
530 globaldata_t gd = mycpu;
ac72c7f4 531 globaldata_t sgd;
3b6b7bd1 532 lwkt_ipiq_t ip;
b12defdc 533 cpumask_t mask;
3b6b7bd1
MD
534 int n;
535
536again:
b12defdc
MD
537 cpu_lfence();
538 mask = gd->gd_ipimask;
539 atomic_clear_cpumask(&gd->gd_ipimask, mask);
540 while (mask) {
541 n = BSFCPUMASK(mask);
3b6b7bd1 542 if (n != gd->gd_cpuid) {
ac72c7f4
MD
543 sgd = globaldata_find(n);
544 ip = sgd->gd_ipiq;
3b6b7bd1 545 if (ip != NULL) {
c7eb0589 546 while (lwkt_process_ipiq_core(sgd, &ip[gd->gd_cpuid], frame))
3b6b7bd1
MD
547 ;
548 }
549 }
b12defdc 550 mask &= ~CPUMASK(n);
3b6b7bd1
MD
551 }
552 if (gd->gd_cpusyncq.ip_rindex != gd->gd_cpusyncq.ip_windex) {
c7eb0589 553 if (lwkt_process_ipiq_core(gd, &gd->gd_cpusyncq, frame)) {
0f7a3396
MD
554 if (gd->gd_curthread->td_cscount == 0)
555 goto again;
da0b0e8b 556 /* need_ipiq(); do not reflag */
0f7a3396 557 }
3b6b7bd1 558 }
b12defdc
MD
559
560 /*
561 * Interlock to allow more IPI interrupts. Recheck ipimask after
562 * releasing gd_npoll.
563 */
564 if (gd->gd_ipimask)
565 goto again;
566 atomic_poll_release_int(&gd->gd_npoll);
567 cpu_mfence();
568 if (gd->gd_ipimask)
569 goto again;
3b6b7bd1 570}
3b6b7bd1 571
cfaeae2a
MD
572#if 0
573static int iqticks[SMP_MAXCPU];
574static int iqcount[SMP_MAXCPU];
575#endif
576#if 0
577static int iqterm[SMP_MAXCPU];
578#endif
579
3b6b7bd1 580static int
b8a98473
MD
581lwkt_process_ipiq_core(globaldata_t sgd, lwkt_ipiq_t ip,
582 struct intrframe *frame)
3b6b7bd1 583{
2de4f77e 584 globaldata_t mygd = mycpu;
3b6b7bd1 585 int ri;
35238fa5 586 int wi;
b8a98473
MD
587 ipifunc3_t copy_func;
588 void *copy_arg1;
589 int copy_arg2;
35238fa5 590
cfaeae2a
MD
591#if 0
592 if (iqticks[mygd->gd_cpuid] != ticks) {
593 iqticks[mygd->gd_cpuid] = ticks;
594 iqcount[mygd->gd_cpuid] = 0;
595 }
596 if (++iqcount[mygd->gd_cpuid] > 3000000) {
597 kprintf("cpu %d ipiq maxed cscount %d spin %d\n",
598 mygd->gd_cpuid,
599 mygd->gd_curthread->td_cscount,
600 mygd->gd_spinlocks_wr);
601 iqcount[mygd->gd_cpuid] = 0;
602#if 0
603 if (++iqterm[mygd->gd_cpuid] > 10)
604 panic("cpu %d ipiq maxed", mygd->gd_cpuid);
605#endif
606 int i;
607 for (i = 0; i < ncpus; ++i) {
608 if (globaldata_find(i)->gd_infomsg)
609 kprintf(" %s", globaldata_find(i)->gd_infomsg);
610 }
611 kprintf("\n");
612 }
613#endif
614
35238fa5 615 /*
b12defdc
MD
616 * Clear the originating core from our ipimask, we will process all
617 * incoming messages.
618 *
35238fa5
MD
619 * Obtain the current write index, which is modified by a remote cpu.
620 * Issue a load fence to prevent speculative reads of e.g. data written
621 * by the other cpu prior to it updating the index.
622 */
f9235b6d 623 KKASSERT(curthread->td_critcount);
35238fa5
MD
624 wi = ip->ip_windex;
625 cpu_lfence();
2de4f77e 626 ++mygd->gd_intr_nesting_level;
35238fa5 627
3b6b7bd1 628 /*
562273ea
MD
629 * NOTE: xindex is only updated after we are sure the function has
630 * finished execution. Beware lwkt_process_ipiq() reentrancy!
631 * The function may send an IPI which may block/drain.
d64a7617 632 *
562273ea
MD
633 * NOTE: Due to additional IPI operations that the callback function
634 * may make, it is possible for both rindex and windex to advance and
635 * thus for rindex to advance passed our cached windex.
636 *
d5b2d319 637 * NOTE: A load fence is required to prevent speculative loads prior
562273ea 638 * to the loading of ip_rindex. Even though stores might be
d5b2d319
MD
639 * ordered, loads are probably not. A memory fence is required
640 * to prevent reordering of the loads after the ip_rindex update.
3b6b7bd1 641 */
d64a7617 642 while (wi - (ri = ip->ip_rindex) > 0) {
3b6b7bd1 643 ri &= MAXCPUFIFO_MASK;
d5b2d319 644 cpu_lfence();
b12defdc
MD
645 copy_func = ip->ip_info[ri].func;
646 copy_arg1 = ip->ip_info[ri].arg1;
647 copy_arg2 = ip->ip_info[ri].arg2;
d5b2d319 648 cpu_mfence();
728f6208 649 ++ip->ip_rindex;
562273ea
MD
650 KKASSERT((ip->ip_rindex & MAXCPUFIFO_MASK) ==
651 ((ri + 1) & MAXCPUFIFO_MASK));
a7adb95a 652 logipiq(receive, copy_func, copy_arg1, copy_arg2, sgd, mycpu);
d5b2d319
MD
653#ifdef INVARIANTS
654 if (ipiq_debug && (ip->ip_rindex & 0xFFFFFF) == 0) {
655 kprintf("cpu %d ipifunc %p %p %d (frame %p)\n",
656 mycpu->gd_cpuid,
657 copy_func, copy_arg1, copy_arg2,
658#if defined(__i386__)
659 (frame ? (void *)frame->if_eip : NULL));
660#elif defined(__amd64__)
661 (frame ? (void *)frame->if_rip : NULL));
662#else
663 NULL);
664#endif
665 }
666#endif
b8a98473 667 copy_func(copy_arg1, copy_arg2, frame);
35238fa5 668 cpu_sfence();
3b6b7bd1 669 ip->ip_xindex = ip->ip_rindex;
e8f15168
MD
670
671#ifdef PANIC_DEBUG
672 /*
673 * Simulate panics during the processing of an IPI
674 */
675 if (mycpu->gd_cpuid == panic_ipiq_cpu && panic_ipiq_count) {
676 if (--panic_ipiq_count == 0) {
677#ifdef DDB
678 Debugger("PANIC_DEBUG");
679#else
680 panic("PANIC_DEBUG");
681#endif
682 }
683 }
684#endif
3b6b7bd1 685 }
2de4f77e 686 --mygd->gd_intr_nesting_level;
4c9f5a7f
MD
687
688 /*
b12defdc 689 * Return non-zero if there is still more in the queue.
4c9f5a7f 690 */
da0b0e8b
MD
691 cpu_lfence();
692 return (ip->ip_rindex != ip->ip_windex);
3b6b7bd1
MD
693}
694
6c92c1f2
SZ
695static void
696lwkt_sync_ipiq(void *arg)
697{
5a1a2253 698 volatile cpumask_t *cpumask = arg;
6c92c1f2 699
da23a592 700 atomic_clear_cpumask(cpumask, mycpu->gd_cpumask);
6c92c1f2
SZ
701 if (*cpumask == 0)
702 wakeup(cpumask);
703}
704
705void
706lwkt_synchronize_ipiqs(const char *wmesg)
707{
5a1a2253 708 volatile cpumask_t other_cpumask;
6c92c1f2
SZ
709
710 other_cpumask = mycpu->gd_other_cpus & smp_active_mask;
5a1a2253
SZ
711 lwkt_send_ipiq_mask(other_cpumask, lwkt_sync_ipiq,
712 __DEVOLATILE(void *, &other_cpumask));
6c92c1f2 713
6c92c1f2 714 while (other_cpumask != 0) {
ae8e83e6 715 tsleep_interlock(&other_cpumask, 0);
6c92c1f2 716 if (other_cpumask != 0)
d9345d3a 717 tsleep(&other_cpumask, PINTERLOCKED, wmesg, 0);
6c92c1f2 718 }
6c92c1f2
SZ
719}
720
0f7a3396
MD
721#endif
722
3b6b7bd1
MD
723/*
724 * CPU Synchronization Support
5c71a36a 725 *
d5b2d319
MD
726 * lwkt_cpusync_interlock() - Place specified cpus in a quiescent state.
727 * The current cpu is placed in a hard critical
728 * section.
5c71a36a 729 *
d5b2d319
MD
730 * lwkt_cpusync_deinterlock() - Execute cs_func on specified cpus, including
731 * current cpu if specified, then return.
3b6b7bd1 732 */
3b6b7bd1 733void
d5b2d319 734lwkt_cpusync_simple(cpumask_t mask, cpusync_func_t func, void *arg)
5c71a36a 735{
d5b2d319 736 struct lwkt_cpusync cs;
5c71a36a 737
d5b2d319
MD
738 lwkt_cpusync_init(&cs, mask, func, arg);
739 lwkt_cpusync_interlock(&cs);
740 lwkt_cpusync_deinterlock(&cs);
3b6b7bd1
MD
741}
742
d5b2d319 743
5c71a36a 744void
d5b2d319 745lwkt_cpusync_interlock(lwkt_cpusync_t cs)
3b6b7bd1 746{
d5b2d319 747#ifdef SMP
b12defdc
MD
748#if 0
749 const char *smsg = "SMPSYNL";
750#endif
0f7a3396 751 globaldata_t gd = mycpu;
d5b2d319 752 cpumask_t mask;
0f7a3396 753
d5b2d319
MD
754 /*
755 * mask acknowledge (cs_mack): 0->mask for stage 1
756 *
757 * mack does not include the current cpu.
758 */
759 mask = cs->cs_mask & gd->gd_other_cpus & smp_active_mask;
760 cs->cs_mack = 0;
761 crit_enter_id("cpusync");
762 if (mask) {
cfaeae2a 763 DEBUG_PUSH_INFO("cpusync_interlock");
0f7a3396
MD
764 ++ipiq_cscount;
765 ++gd->gd_curthread->td_cscount;
d5b2d319
MD
766 lwkt_send_ipiq_mask(mask, (ipifunc1_t)lwkt_cpusync_remote1, cs);
767 logipiq2(sync_start, mask);
b12defdc
MD
768#if 0
769 if (gd->gd_curthread->td_wmesg == NULL)
770 gd->gd_curthread->td_wmesg = smsg;
771#endif
d5b2d319 772 while (cs->cs_mack != mask) {
0f7a3396 773 lwkt_process_ipiq();
d5b2d319 774 cpu_pause();
0f7a3396 775 }
b12defdc
MD
776#if 0
777 if (gd->gd_curthread->td_wmesg == smsg)
778 gd->gd_curthread->td_wmesg = NULL;
779#endif
cfaeae2a 780 DEBUG_POP_INFO();
3b6b7bd1 781 }
d5b2d319
MD
782#else
783 cs->cs_mack = 0;
0f7a3396 784#endif
3b6b7bd1
MD
785}
786
787/*
d5b2d319
MD
788 * Interlocked cpus have executed remote1 and are polling in remote2.
789 * To deinterlock we clear cs_mack and wait for the cpus to execute
790 * the func and set their bit in cs_mack again.
0f7a3396 791 *
3b6b7bd1
MD
792 */
793void
d5b2d319 794lwkt_cpusync_deinterlock(lwkt_cpusync_t cs)
3b6b7bd1 795{
0f7a3396 796 globaldata_t gd = mycpu;
0f7a3396 797#ifdef SMP
b12defdc
MD
798#if 0
799 const char *smsg = "SMPSYNU";
800#endif
d5b2d319
MD
801 cpumask_t mask;
802
803 /*
804 * mask acknowledge (cs_mack): mack->0->mack for stage 2
805 *
806 * Clearing cpu bits for polling cpus in cs_mack will cause them to
807 * execute stage 2, which executes the cs_func(cs_data) and then sets
808 * their bit in cs_mack again.
809 *
810 * mack does not include the current cpu.
811 */
812 mask = cs->cs_mack;
813 cpu_ccfence();
814 cs->cs_mack = 0;
815 if (cs->cs_func && (cs->cs_mask & gd->gd_cpumask))
816 cs->cs_func(cs->cs_data);
817 if (mask) {
cfaeae2a 818 DEBUG_PUSH_INFO("cpusync_deinterlock");
b12defdc
MD
819#if 0
820 if (gd->gd_curthread->td_wmesg == NULL)
821 gd->gd_curthread->td_wmesg = smsg;
822#endif
d5b2d319 823 while (cs->cs_mack != mask) {
0f7a3396 824 lwkt_process_ipiq();
d5b2d319 825 cpu_pause();
0f7a3396 826 }
b12defdc
MD
827#if 0
828 if (gd->gd_curthread->td_wmesg == smsg)
829 gd->gd_curthread->td_wmesg = NULL;
830#endif
cfaeae2a
MD
831 DEBUG_POP_INFO();
832 /*
833 * cpusyncq ipis may be left queued without the RQF flag set due to
834 * a non-zero td_cscount, so be sure to process any laggards after
835 * decrementing td_cscount.
836 */
0f7a3396 837 --gd->gd_curthread->td_cscount;
d5b2d319
MD
838 lwkt_process_ipiq();
839 logipiq2(sync_end, mask);
3b6b7bd1 840 }
d5b2d319
MD
841 crit_exit_id("cpusync");
842#else
843 if (cs->cs_func && (cs->cs_mask & gd->gd_cpumask))
844 cs->cs_func(cs->cs_data);
0f7a3396 845#endif
3b6b7bd1
MD
846}
847
0f7a3396
MD
848#ifdef SMP
849
3b6b7bd1
MD
850/*
851 * helper IPI remote messaging function.
852 *
853 * Called on remote cpu when a new cpu synchronization request has been
854 * sent to us. Execute the run function and adjust cs_count, then requeue
855 * the request so we spin on it.
856 */
857static void
d5b2d319 858lwkt_cpusync_remote1(lwkt_cpusync_t cs)
3b6b7bd1 859{
d5b2d319
MD
860 globaldata_t gd = mycpu;
861
862 atomic_set_cpumask(&cs->cs_mack, gd->gd_cpumask);
863 lwkt_cpusync_remote2(cs);
3b6b7bd1
MD
864}
865
866/*
867 * helper IPI remote messaging function.
868 *
869 * Poll for the originator telling us to finish. If it hasn't, requeue
d5b2d319 870 * our request so we spin on it.
3b6b7bd1
MD
871 */
872static void
d5b2d319 873lwkt_cpusync_remote2(lwkt_cpusync_t cs)
3b6b7bd1 874{
d5b2d319
MD
875 globaldata_t gd = mycpu;
876
877 if ((cs->cs_mack & gd->gd_cpumask) == 0) {
878 if (cs->cs_func)
879 cs->cs_func(cs->cs_data);
880 atomic_set_cpumask(&cs->cs_mack, gd->gd_cpumask);
3b6b7bd1 881 } else {
3b6b7bd1
MD
882 lwkt_ipiq_t ip;
883 int wi;
884
885 ip = &gd->gd_cpusyncq;
886 wi = ip->ip_windex & MAXCPUFIFO_MASK;
b12defdc
MD
887 ip->ip_info[wi].func = (ipifunc3_t)(ipifunc1_t)lwkt_cpusync_remote2;
888 ip->ip_info[wi].arg1 = cs;
889 ip->ip_info[wi].arg2 = 0;
35238fa5 890 cpu_sfence();
3b6b7bd1 891 ++ip->ip_windex;
37494a7a 892 if (ipiq_debug && (ip->ip_windex & 0xFFFFFF) == 0) {
cfaeae2a
MD
893 kprintf("cpu %d cm=%016jx %016jx f=%p\n",
894 gd->gd_cpuid,
895 (intmax_t)cs->cs_mask, (intmax_t)cs->cs_mack,
896 cs->cs_func);
37494a7a 897 }
3b6b7bd1
MD
898 }
899}
900
3b6b7bd1 901#endif