2 * Copyright (c) 2003,2004 The DragonFly Project. All rights reserved.
4 * This code is derived from software contributed to The DragonFly Project
5 * by Matthew Dillon <dillon@backplane.com>
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
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
14 * notice, this list of conditions and the following disclaimer in
15 * the documentation and/or other materials provided with the
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.
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
36 * This module implements IPI message queueing and the MI portion of IPI
42 #include <sys/param.h>
43 #include <sys/systm.h>
44 #include <sys/kernel.h>
46 #include <sys/rtprio.h>
47 #include <sys/queue.h>
48 #include <sys/thread2.h>
49 #include <sys/sysctl.h>
51 #include <sys/kthread.h>
52 #include <machine/cpu.h>
56 #include <vm/vm_param.h>
57 #include <vm/vm_kern.h>
58 #include <vm/vm_object.h>
59 #include <vm/vm_page.h>
60 #include <vm/vm_map.h>
61 #include <vm/vm_pager.h>
62 #include <vm/vm_extern.h>
63 #include <vm/vm_zone.h>
65 #include <machine/stdarg.h>
66 #include <machine/smp.h>
67 #include <machine/atomic.h>
70 __int64_t ipiq_count; /* total calls to lwkt_send_ipiq*() */
71 __int64_t ipiq_fifofull; /* number of fifo full conditions detected */
72 __int64_t ipiq_avoided; /* interlock with target avoids cpu ipi */
73 __int64_t ipiq_passive; /* passive IPI messages */
74 __int64_t ipiq_cscount; /* number of cpu synchronizations */
77 static struct ipiq_stats ipiq_stats_percpu[MAXCPU];
78 #define ipiq_stat(gd) ipiq_stats_percpu[(gd)->gd_cpuid]
80 static int ipiq_debug; /* set to 1 for debug */
82 static int panic_ipiq_cpu = -1;
83 static int panic_ipiq_count = 100;
86 SYSCTL_INT(_lwkt, OID_AUTO, ipiq_debug, CTLFLAG_RW, &ipiq_debug, 0,
89 SYSCTL_INT(_lwkt, OID_AUTO, panic_ipiq_cpu, CTLFLAG_RW, &panic_ipiq_cpu, 0, "");
90 SYSCTL_INT(_lwkt, OID_AUTO, panic_ipiq_count, CTLFLAG_RW, &panic_ipiq_count, 0, "");
93 #define IPIQ_STRING "func=%p arg1=%p arg2=%d scpu=%d dcpu=%d"
94 #define IPIQ_ARGS void *func, void *arg1, int arg2, int scpu, int dcpu
96 #if !defined(KTR_IPIQ)
97 #define KTR_IPIQ KTR_ALL
99 KTR_INFO_MASTER(ipiq);
100 KTR_INFO(KTR_IPIQ, ipiq, send_norm, 0, IPIQ_STRING, IPIQ_ARGS);
101 KTR_INFO(KTR_IPIQ, ipiq, send_pasv, 1, IPIQ_STRING, IPIQ_ARGS);
102 KTR_INFO(KTR_IPIQ, ipiq, send_nbio, 2, IPIQ_STRING, IPIQ_ARGS);
103 KTR_INFO(KTR_IPIQ, ipiq, send_fail, 3, IPIQ_STRING, IPIQ_ARGS);
104 KTR_INFO(KTR_IPIQ, ipiq, receive, 4, IPIQ_STRING, IPIQ_ARGS);
105 KTR_INFO(KTR_IPIQ, ipiq, sync_start, 5, "cpumask=%08lx", unsigned long mask);
106 KTR_INFO(KTR_IPIQ, ipiq, sync_end, 6, "cpumask=%08lx", unsigned long mask);
107 KTR_INFO(KTR_IPIQ, ipiq, cpu_send, 7, IPIQ_STRING, IPIQ_ARGS);
108 KTR_INFO(KTR_IPIQ, ipiq, send_end, 8, IPIQ_STRING, IPIQ_ARGS);
110 #define logipiq(name, func, arg1, arg2, sgd, dgd) \
111 KTR_LOG(ipiq_ ## name, func, arg1, arg2, sgd->gd_cpuid, dgd->gd_cpuid)
112 #define logipiq2(name, arg) \
113 KTR_LOG(ipiq_ ## name, arg)
115 static int lwkt_process_ipiq_core(globaldata_t sgd, lwkt_ipiq_t ip,
116 struct intrframe *frame);
117 static void lwkt_cpusync_remote1(lwkt_cpusync_t cs);
118 static void lwkt_cpusync_remote2(lwkt_cpusync_t cs);
120 #define IPIQ_SYSCTL(name) \
122 sysctl_##name(SYSCTL_HANDLER_ARGS) \
127 for (cpu = 0; cpu < ncpus; ++cpu) \
128 val += ipiq_stats_percpu[cpu].name; \
130 error = sysctl_handle_quad(oidp, &val, 0, req); \
131 if (error || req->newptr == NULL) \
134 for (cpu = 0; cpu < ncpus; ++cpu) \
135 ipiq_stats_percpu[cpu].name = val; \
140 IPIQ_SYSCTL(ipiq_count);
141 IPIQ_SYSCTL(ipiq_fifofull);
142 IPIQ_SYSCTL(ipiq_avoided);
143 IPIQ_SYSCTL(ipiq_passive);
144 IPIQ_SYSCTL(ipiq_cscount);
146 SYSCTL_PROC(_lwkt, OID_AUTO, ipiq_count, (CTLTYPE_QUAD | CTLFLAG_RW),
147 0, 0, sysctl_ipiq_count, "Q", "Number of IPI's sent");
148 SYSCTL_PROC(_lwkt, OID_AUTO, ipiq_fifofull, (CTLTYPE_QUAD | CTLFLAG_RW),
149 0, 0, sysctl_ipiq_fifofull, "Q",
150 "Number of fifo full conditions detected");
151 SYSCTL_PROC(_lwkt, OID_AUTO, ipiq_avoided, (CTLTYPE_QUAD | CTLFLAG_RW),
152 0, 0, sysctl_ipiq_avoided, "Q",
153 "Number of IPI's avoided by interlock with target cpu");
154 SYSCTL_PROC(_lwkt, OID_AUTO, ipiq_passive, (CTLTYPE_QUAD | CTLFLAG_RW),
155 0, 0, sysctl_ipiq_passive, "Q",
156 "Number of passive IPI messages sent");
157 SYSCTL_PROC(_lwkt, OID_AUTO, ipiq_cscount, (CTLTYPE_QUAD | CTLFLAG_RW),
158 0, 0, sysctl_ipiq_cscount, "Q",
159 "Number of cpu synchronizations");
162 * Send a function execution request to another cpu. The request is queued
163 * on the cpu<->cpu ipiq matrix. Each cpu owns a unique ipiq FIFO for every
164 * possible target cpu. The FIFO can be written.
166 * If the FIFO fills up we have to enable interrupts to avoid an APIC
167 * deadlock and process pending IPIQs while waiting for it to empty.
168 * Otherwise we may soft-deadlock with another cpu whos FIFO is also full.
170 * We can safely bump gd_intr_nesting_level because our crit_exit() at the
171 * end will take care of any pending interrupts.
173 * The actual hardware IPI is avoided if the target cpu is already processing
174 * the queue from a prior IPI. It is possible to pipeline IPI messages
175 * very quickly between cpus due to the FIFO hysteresis.
177 * Need not be called from a critical section.
180 lwkt_send_ipiq3(globaldata_t target, ipifunc3_t func, void *arg1, int arg2)
184 struct globaldata *gd = mycpu;
186 logipiq(send_norm, func, arg1, arg2, gd, target);
189 func(arg1, arg2, NULL);
190 logipiq(send_end, func, arg1, arg2, gd, target);
194 ++gd->gd_intr_nesting_level;
196 if (gd->gd_intr_nesting_level > 20)
197 panic("lwkt_send_ipiq: TOO HEAVILY NESTED!");
199 KKASSERT(curthread->td_critcount);
200 ++ipiq_stat(gd).ipiq_count;
201 ip = &gd->gd_ipiq[target->gd_cpuid];
204 * Do not allow the FIFO to become full. Interrupts must be physically
205 * enabled while we liveloop to avoid deadlocking the APIC.
207 * The target ipiq may have gotten filled up due to passive IPIs and thus
208 * not be aware that its queue is too full, so be sure to issue an
209 * ipiq interrupt to the target cpu.
211 if (ip->ip_windex - ip->ip_rindex > MAXCPUFIFO / 2) {
212 #if defined(__i386__)
213 unsigned int eflags = read_eflags();
214 #elif defined(__x86_64__)
215 unsigned long rflags = read_rflags();
219 ++ipiq_stat(gd).ipiq_fifofull;
220 DEBUG_PUSH_INFO("send_ipiq3");
221 while (ip->ip_windex - ip->ip_rindex > MAXCPUFIFO / 4) {
222 if (atomic_poll_acquire_int(&target->gd_npoll)) {
223 logipiq(cpu_send, func, arg1, arg2, gd, target);
224 cpu_send_ipiq(target->gd_cpuid);
226 KKASSERT(ip->ip_windex - ip->ip_rindex != MAXCPUFIFO - 1);
231 #if defined(__i386__)
232 write_eflags(eflags);
233 #elif defined(__x86_64__)
234 write_rflags(rflags);
239 * Queue the new message
241 windex = ip->ip_windex & MAXCPUFIFO_MASK;
242 ip->ip_info[windex].func = func;
243 ip->ip_info[windex].arg1 = arg1;
244 ip->ip_info[windex].arg2 = arg2;
247 atomic_set_cpumask(&target->gd_ipimask, gd->gd_cpumask);
250 * signal the target cpu that there is work pending.
252 if (atomic_poll_acquire_int(&target->gd_npoll)) {
253 logipiq(cpu_send, func, arg1, arg2, gd, target);
254 cpu_send_ipiq(target->gd_cpuid);
256 ++ipiq_stat(gd).ipiq_avoided;
258 --gd->gd_intr_nesting_level;
260 logipiq(send_end, func, arg1, arg2, gd, target);
262 return(ip->ip_windex);
266 * Similar to lwkt_send_ipiq() but this function does not actually initiate
267 * the IPI to the target cpu unless the FIFO has become too full, so it is
270 * This function is used for non-critical IPI messages, such as memory
271 * deallocations. The queue will typically be flushed by the target cpu at
272 * the next clock interrupt.
274 * Need not be called from a critical section.
277 lwkt_send_ipiq3_passive(globaldata_t target, ipifunc3_t func,
278 void *arg1, int arg2)
282 struct globaldata *gd = mycpu;
284 KKASSERT(target != gd);
286 ++gd->gd_intr_nesting_level;
287 logipiq(send_pasv, func, arg1, arg2, gd, target);
289 if (gd->gd_intr_nesting_level > 20)
290 panic("lwkt_send_ipiq: TOO HEAVILY NESTED!");
292 KKASSERT(curthread->td_critcount);
293 ++ipiq_stat(gd).ipiq_count;
294 ++ipiq_stat(gd).ipiq_passive;
295 ip = &gd->gd_ipiq[target->gd_cpuid];
298 * Do not allow the FIFO to become full. Interrupts must be physically
299 * enabled while we liveloop to avoid deadlocking the APIC.
301 if (ip->ip_windex - ip->ip_rindex > MAXCPUFIFO / 2) {
302 #if defined(__i386__)
303 unsigned int eflags = read_eflags();
304 #elif defined(__x86_64__)
305 unsigned long rflags = read_rflags();
309 ++ipiq_stat(gd).ipiq_fifofull;
310 DEBUG_PUSH_INFO("send_ipiq3_passive");
311 while (ip->ip_windex - ip->ip_rindex > MAXCPUFIFO / 4) {
312 if (atomic_poll_acquire_int(&target->gd_npoll)) {
313 logipiq(cpu_send, func, arg1, arg2, gd, target);
314 cpu_send_ipiq(target->gd_cpuid);
316 KKASSERT(ip->ip_windex - ip->ip_rindex != MAXCPUFIFO - 1);
321 #if defined(__i386__)
322 write_eflags(eflags);
323 #elif defined(__x86_64__)
324 write_rflags(rflags);
329 * Queue the new message
331 windex = ip->ip_windex & MAXCPUFIFO_MASK;
332 ip->ip_info[windex].func = func;
333 ip->ip_info[windex].arg1 = arg1;
334 ip->ip_info[windex].arg2 = arg2;
337 atomic_set_cpumask(&target->gd_ipimask, gd->gd_cpumask);
338 --gd->gd_intr_nesting_level;
341 * Do not signal the target cpu, it will pick up the IPI when it next
342 * polls (typically on the next tick).
345 logipiq(send_end, func, arg1, arg2, gd, target);
347 return(ip->ip_windex);
351 * Send an IPI request without blocking, return 0 on success, ENOENT on
352 * failure. The actual queueing of the hardware IPI may still force us
353 * to spin and process incoming IPIs but that will eventually go away
354 * when we've gotten rid of the other general IPIs.
357 lwkt_send_ipiq3_nowait(globaldata_t target, ipifunc3_t func,
358 void *arg1, int arg2)
362 struct globaldata *gd = mycpu;
364 logipiq(send_nbio, func, arg1, arg2, gd, target);
365 KKASSERT(curthread->td_critcount);
367 func(arg1, arg2, NULL);
368 logipiq(send_end, func, arg1, arg2, gd, target);
372 ++gd->gd_intr_nesting_level;
373 ++ipiq_stat(gd).ipiq_count;
374 ip = &gd->gd_ipiq[target->gd_cpuid];
376 if (ip->ip_windex - ip->ip_rindex >= MAXCPUFIFO * 2 / 3) {
377 logipiq(send_fail, func, arg1, arg2, gd, target);
378 --gd->gd_intr_nesting_level;
382 windex = ip->ip_windex & MAXCPUFIFO_MASK;
383 ip->ip_info[windex].func = func;
384 ip->ip_info[windex].arg1 = arg1;
385 ip->ip_info[windex].arg2 = arg2;
388 atomic_set_cpumask(&target->gd_ipimask, gd->gd_cpumask);
391 * This isn't a passive IPI, we still have to signal the target cpu.
393 if (atomic_poll_acquire_int(&target->gd_npoll)) {
394 logipiq(cpu_send, func, arg1, arg2, gd, target);
395 cpu_send_ipiq(target->gd_cpuid);
397 ++ipiq_stat(gd).ipiq_avoided;
399 --gd->gd_intr_nesting_level;
402 logipiq(send_end, func, arg1, arg2, gd, target);
407 * deprecated, used only by fast int forwarding.
410 lwkt_send_ipiq3_bycpu(int dcpu, ipifunc3_t func, void *arg1, int arg2)
412 return(lwkt_send_ipiq3(globaldata_find(dcpu), func, arg1, arg2));
416 * Send a message to several target cpus. Typically used for scheduling.
417 * The message will not be sent to stopped cpus.
420 lwkt_send_ipiq3_mask(cpumask_t mask, ipifunc3_t func, void *arg1, int arg2)
425 mask &= ~stopped_cpus;
427 cpuid = BSFCPUMASK(mask);
428 lwkt_send_ipiq3(globaldata_find(cpuid), func, arg1, arg2);
429 mask &= ~CPUMASK(cpuid);
436 * Wait for the remote cpu to finish processing a function.
438 * YYY we have to enable interrupts and process the IPIQ while waiting
439 * for it to empty or we may deadlock with another cpu. Create a CPU_*()
440 * function to do this! YYY we really should 'block' here.
442 * MUST be called from a critical section. This routine may be called
443 * from an interrupt (for example, if an interrupt wakes a foreign thread
447 lwkt_wait_ipiq(globaldata_t target, int seq)
451 if (target != mycpu) {
452 ip = &mycpu->gd_ipiq[target->gd_cpuid];
453 if ((int)(ip->ip_xindex - seq) < 0) {
454 #if defined(__i386__)
455 unsigned int eflags = read_eflags();
456 #elif defined(__x86_64__)
457 unsigned long rflags = read_rflags();
459 int64_t time_tgt = tsc_get_target(1000000000LL);
464 DEBUG_PUSH_INFO("wait_ipiq");
465 while ((int)(ip->ip_xindex - seq) < 0) {
471 * IPIQs must be handled within 10 seconds and this code
472 * will warn after one second.
474 if ((benice & 255) == 0 && tsc_test_target(time_tgt) > 0) {
475 kprintf("LWKT_WAIT_IPIQ WARNING! %d wait %d (%d)\n",
476 mycpu->gd_cpuid, target->gd_cpuid,
477 ip->ip_xindex - seq);
478 if (--time_loops == 0)
479 panic("LWKT_WAIT_IPIQ");
480 time_tgt = tsc_get_target(1000000000LL);
485 * xindex may be modified by another cpu, use a load fence
486 * to ensure that the loop does not use a speculative value
487 * (which may improve performance).
492 #if defined(__i386__)
493 write_eflags(eflags);
494 #elif defined(__x86_64__)
495 write_rflags(rflags);
502 lwkt_seq_ipiq(globaldata_t target)
506 ip = &mycpu->gd_ipiq[target->gd_cpuid];
507 return(ip->ip_windex);
511 * Called from IPI interrupt (like a fast interrupt), which has placed
512 * us in a critical section. The MP lock may or may not be held.
513 * May also be called from doreti or splz, or be reentrantly called
514 * indirectly through the ip_info[].func we run.
516 * There are two versions, one where no interrupt frame is available (when
517 * called from the send code and from splz, and one where an interrupt
518 * frame is available.
520 * When the current cpu is mastering a cpusync we do NOT internally loop
521 * on the cpusyncq poll. We also do not re-flag a pending ipi due to
522 * the cpusyncq poll because this can cause doreti/splz to loop internally.
523 * The cpusync master's own loop must be allowed to run to avoid a deadlock.
526 lwkt_process_ipiq(void)
528 globaldata_t gd = mycpu;
534 ++gd->gd_processing_ipiq;
537 mask = gd->gd_ipimask;
538 atomic_clear_cpumask(&gd->gd_ipimask, mask);
540 n = BSFCPUMASK(mask);
541 if (n != gd->gd_cpuid) {
542 sgd = globaldata_find(n);
545 while (lwkt_process_ipiq_core(sgd, &ip[gd->gd_cpuid], NULL))
553 * Process pending cpusyncs. If the current thread has a cpusync
554 * active cpusync we only run the list once and do not re-flag
555 * as the thread itself is processing its interlock.
557 if (lwkt_process_ipiq_core(gd, &gd->gd_cpusyncq, NULL)) {
558 if (gd->gd_curthread->td_cscount == 0)
560 /* need_ipiq(); do not reflag */
564 * Interlock to allow more IPI interrupts. Recheck ipimask after
565 * releasing gd_npoll.
569 atomic_poll_release_int(&gd->gd_npoll);
573 --gd->gd_processing_ipiq;
577 lwkt_process_ipiq_frame(struct intrframe *frame)
579 globaldata_t gd = mycpu;
587 mask = gd->gd_ipimask;
588 atomic_clear_cpumask(&gd->gd_ipimask, mask);
590 n = BSFCPUMASK(mask);
591 if (n != gd->gd_cpuid) {
592 sgd = globaldata_find(n);
595 while (lwkt_process_ipiq_core(sgd, &ip[gd->gd_cpuid], frame))
601 if (gd->gd_cpusyncq.ip_rindex != gd->gd_cpusyncq.ip_windex) {
602 if (lwkt_process_ipiq_core(gd, &gd->gd_cpusyncq, frame)) {
603 if (gd->gd_curthread->td_cscount == 0)
605 /* need_ipiq(); do not reflag */
610 * Interlock to allow more IPI interrupts. Recheck ipimask after
611 * releasing gd_npoll.
615 atomic_poll_release_int(&gd->gd_npoll);
622 static int iqticks[SMP_MAXCPU];
623 static int iqcount[SMP_MAXCPU];
626 static int iqterm[SMP_MAXCPU];
630 lwkt_process_ipiq_core(globaldata_t sgd, lwkt_ipiq_t ip,
631 struct intrframe *frame)
633 globaldata_t mygd = mycpu;
636 ipifunc3_t copy_func;
641 if (iqticks[mygd->gd_cpuid] != ticks) {
642 iqticks[mygd->gd_cpuid] = ticks;
643 iqcount[mygd->gd_cpuid] = 0;
645 if (++iqcount[mygd->gd_cpuid] > 3000000) {
646 kprintf("cpu %d ipiq maxed cscount %d spin %d\n",
648 mygd->gd_curthread->td_cscount,
650 iqcount[mygd->gd_cpuid] = 0;
652 if (++iqterm[mygd->gd_cpuid] > 10)
653 panic("cpu %d ipiq maxed", mygd->gd_cpuid);
656 for (i = 0; i < ncpus; ++i) {
657 if (globaldata_find(i)->gd_infomsg)
658 kprintf(" %s", globaldata_find(i)->gd_infomsg);
665 * Clear the originating core from our ipimask, we will process all
668 * Obtain the current write index, which is modified by a remote cpu.
669 * Issue a load fence to prevent speculative reads of e.g. data written
670 * by the other cpu prior to it updating the index.
672 KKASSERT(curthread->td_critcount);
675 ++mygd->gd_intr_nesting_level;
678 * NOTE: xindex is only updated after we are sure the function has
679 * finished execution. Beware lwkt_process_ipiq() reentrancy!
680 * The function may send an IPI which may block/drain.
682 * NOTE: Due to additional IPI operations that the callback function
683 * may make, it is possible for both rindex and windex to advance and
684 * thus for rindex to advance passed our cached windex.
686 * NOTE: A load fence is required to prevent speculative loads prior
687 * to the loading of ip_rindex. Even though stores might be
688 * ordered, loads are probably not. A memory fence is required
689 * to prevent reordering of the loads after the ip_rindex update.
691 * NOTE: Single pass only. Returns non-zero if the queue is not empty
694 while (wi - (ri = ip->ip_rindex) > 0) {
695 ri &= MAXCPUFIFO_MASK;
697 copy_func = ip->ip_info[ri].func;
698 copy_arg1 = ip->ip_info[ri].arg1;
699 copy_arg2 = ip->ip_info[ri].arg2;
702 KKASSERT((ip->ip_rindex & MAXCPUFIFO_MASK) ==
703 ((ri + 1) & MAXCPUFIFO_MASK));
704 logipiq(receive, copy_func, copy_arg1, copy_arg2, sgd, mycpu);
706 if (ipiq_debug && (ip->ip_rindex & 0xFFFFFF) == 0) {
707 kprintf("cpu %d ipifunc %p %p %d (frame %p)\n",
709 copy_func, copy_arg1, copy_arg2,
710 #if defined(__i386__)
711 (frame ? (void *)frame->if_eip : NULL));
712 #elif defined(__x86_64__)
713 (frame ? (void *)frame->if_rip : NULL));
719 copy_func(copy_arg1, copy_arg2, frame);
721 ip->ip_xindex = ip->ip_rindex;
725 * Simulate panics during the processing of an IPI
727 if (mycpu->gd_cpuid == panic_ipiq_cpu && panic_ipiq_count) {
728 if (--panic_ipiq_count == 0) {
730 Debugger("PANIC_DEBUG");
732 panic("PANIC_DEBUG");
738 --mygd->gd_intr_nesting_level;
741 * Return non-zero if there is still more in the queue.
744 return (ip->ip_rindex != ip->ip_windex);
748 lwkt_sync_ipiq(void *arg)
750 volatile cpumask_t *cpumask = arg;
752 atomic_clear_cpumask(cpumask, mycpu->gd_cpumask);
758 lwkt_synchronize_ipiqs(const char *wmesg)
760 volatile cpumask_t other_cpumask;
762 other_cpumask = mycpu->gd_other_cpus & smp_active_mask;
763 lwkt_send_ipiq_mask(other_cpumask, lwkt_sync_ipiq,
764 __DEVOLATILE(void *, &other_cpumask));
766 while (other_cpumask != 0) {
767 tsleep_interlock(&other_cpumask, 0);
768 if (other_cpumask != 0)
769 tsleep(&other_cpumask, PINTERLOCKED, wmesg, 0);
774 * CPU Synchronization Support
776 * lwkt_cpusync_interlock() - Place specified cpus in a quiescent state.
777 * The current cpu is placed in a hard critical
780 * lwkt_cpusync_deinterlock() - Execute cs_func on specified cpus, including
781 * current cpu if specified, then return.
784 lwkt_cpusync_simple(cpumask_t mask, cpusync_func_t func, void *arg)
786 struct lwkt_cpusync cs;
788 lwkt_cpusync_init(&cs, mask, func, arg);
789 lwkt_cpusync_interlock(&cs);
790 lwkt_cpusync_deinterlock(&cs);
795 lwkt_cpusync_interlock(lwkt_cpusync_t cs)
798 const char *smsg = "SMPSYNL";
800 globaldata_t gd = mycpu;
804 * mask acknowledge (cs_mack): 0->mask for stage 1
806 * mack does not include the current cpu.
808 mask = cs->cs_mask & gd->gd_other_cpus & smp_active_mask;
810 crit_enter_id("cpusync");
812 DEBUG_PUSH_INFO("cpusync_interlock");
813 ++ipiq_stat(gd).ipiq_cscount;
814 ++gd->gd_curthread->td_cscount;
815 lwkt_send_ipiq_mask(mask, (ipifunc1_t)lwkt_cpusync_remote1, cs);
816 logipiq2(sync_start, (long)mask);
818 if (gd->gd_curthread->td_wmesg == NULL)
819 gd->gd_curthread->td_wmesg = smsg;
821 while (cs->cs_mack != mask) {
826 if (gd->gd_curthread->td_wmesg == smsg)
827 gd->gd_curthread->td_wmesg = NULL;
834 * Interlocked cpus have executed remote1 and are polling in remote2.
835 * To deinterlock we clear cs_mack and wait for the cpus to execute
836 * the func and set their bit in cs_mack again.
840 lwkt_cpusync_deinterlock(lwkt_cpusync_t cs)
842 globaldata_t gd = mycpu;
844 const char *smsg = "SMPSYNU";
849 * mask acknowledge (cs_mack): mack->0->mack for stage 2
851 * Clearing cpu bits for polling cpus in cs_mack will cause them to
852 * execute stage 2, which executes the cs_func(cs_data) and then sets
853 * their bit in cs_mack again.
855 * mack does not include the current cpu.
861 if (cs->cs_func && (cs->cs_mask & gd->gd_cpumask))
862 cs->cs_func(cs->cs_data);
864 DEBUG_PUSH_INFO("cpusync_deinterlock");
866 if (gd->gd_curthread->td_wmesg == NULL)
867 gd->gd_curthread->td_wmesg = smsg;
869 while (cs->cs_mack != mask) {
874 if (gd->gd_curthread->td_wmesg == smsg)
875 gd->gd_curthread->td_wmesg = NULL;
879 * cpusyncq ipis may be left queued without the RQF flag set due to
880 * a non-zero td_cscount, so be sure to process any laggards after
881 * decrementing td_cscount.
883 --gd->gd_curthread->td_cscount;
885 logipiq2(sync_end, (long)mask);
887 crit_exit_id("cpusync");
891 * helper IPI remote messaging function.
893 * Called on remote cpu when a new cpu synchronization request has been
894 * sent to us. Execute the run function and adjust cs_count, then requeue
895 * the request so we spin on it.
898 lwkt_cpusync_remote1(lwkt_cpusync_t cs)
900 globaldata_t gd = mycpu;
902 atomic_set_cpumask(&cs->cs_mack, gd->gd_cpumask);
903 lwkt_cpusync_remote2(cs);
907 * helper IPI remote messaging function.
909 * Poll for the originator telling us to finish. If it hasn't, requeue
910 * our request so we spin on it.
913 lwkt_cpusync_remote2(lwkt_cpusync_t cs)
915 globaldata_t gd = mycpu;
917 if ((cs->cs_mack & gd->gd_cpumask) == 0) {
919 cs->cs_func(cs->cs_data);
920 atomic_set_cpumask(&cs->cs_mack, gd->gd_cpumask);
921 /* cs can be ripped out at this point */
926 ip = &gd->gd_cpusyncq;
927 wi = ip->ip_windex & MAXCPUFIFO_MASK;
928 ip->ip_info[wi].func = (ipifunc3_t)(ipifunc1_t)lwkt_cpusync_remote2;
929 ip->ip_info[wi].arg1 = cs;
930 ip->ip_info[wi].arg2 = 0;
932 KKASSERT(ip->ip_windex - ip->ip_rindex < MAXCPUFIFO);
934 if (ipiq_debug && (ip->ip_windex & 0xFFFFFF) == 0) {
935 kprintf("cpu %d cm=%016jx %016jx f=%p\n",
937 (intmax_t)cs->cs_mask, (intmax_t)cs->cs_mack,