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
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15 * the documentation and/or other materials provided with the
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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
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24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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34 * $DragonFly: src/sys/kern/lwkt_ipiq.c,v 1.27 2008/05/18 20:57:56 nth Exp $
38 * This module implements IPI message queueing and the MI portion of IPI
44 #include <sys/param.h>
45 #include <sys/systm.h>
46 #include <sys/kernel.h>
48 #include <sys/rtprio.h>
49 #include <sys/queue.h>
50 #include <sys/thread2.h>
51 #include <sys/sysctl.h>
53 #include <sys/kthread.h>
54 #include <machine/cpu.h>
59 #include <vm/vm_param.h>
60 #include <vm/vm_kern.h>
61 #include <vm/vm_object.h>
62 #include <vm/vm_page.h>
63 #include <vm/vm_map.h>
64 #include <vm/vm_pager.h>
65 #include <vm/vm_extern.h>
66 #include <vm/vm_zone.h>
68 #include <machine/stdarg.h>
69 #include <machine/smp.h>
70 #include <machine/atomic.h>
73 static __int64_t ipiq_count; /* total calls to lwkt_send_ipiq*() */
74 static __int64_t ipiq_fifofull; /* number of fifo full conditions detected */
75 static __int64_t ipiq_avoided; /* interlock with target avoids cpu ipi */
76 static __int64_t ipiq_passive; /* passive IPI messages */
77 static __int64_t ipiq_cscount; /* number of cpu synchronizations */
78 static int ipiq_optimized = 1; /* XXX temporary sysctl */
80 static int panic_ipiq_cpu = -1;
81 static int panic_ipiq_count = 100;
86 SYSCTL_QUAD(_lwkt, OID_AUTO, ipiq_count, CTLFLAG_RW, &ipiq_count, 0, "");
87 SYSCTL_QUAD(_lwkt, OID_AUTO, ipiq_fifofull, CTLFLAG_RW, &ipiq_fifofull, 0, "");
88 SYSCTL_QUAD(_lwkt, OID_AUTO, ipiq_avoided, CTLFLAG_RW, &ipiq_avoided, 0, "");
89 SYSCTL_QUAD(_lwkt, OID_AUTO, ipiq_passive, CTLFLAG_RW, &ipiq_passive, 0, "");
90 SYSCTL_QUAD(_lwkt, OID_AUTO, ipiq_cscount, CTLFLAG_RW, &ipiq_cscount, 0, "");
91 SYSCTL_INT(_lwkt, OID_AUTO, ipiq_optimized, CTLFLAG_RW, &ipiq_optimized, 0, "");
93 SYSCTL_INT(_lwkt, OID_AUTO, panic_ipiq_cpu, CTLFLAG_RW, &panic_ipiq_cpu, 0, "");
94 SYSCTL_INT(_lwkt, OID_AUTO, panic_ipiq_count, CTLFLAG_RW, &panic_ipiq_count, 0, "");
97 #define IPIQ_STRING "func=%p arg1=%p arg2=%d scpu=%d dcpu=%d"
98 #define IPIQ_ARG_SIZE (sizeof(void *) * 2 + sizeof(int) * 3)
100 #if !defined(KTR_IPIQ)
101 #define KTR_IPIQ KTR_ALL
103 KTR_INFO_MASTER(ipiq);
104 KTR_INFO(KTR_IPIQ, ipiq, send_norm, 0, IPIQ_STRING, IPIQ_ARG_SIZE);
105 KTR_INFO(KTR_IPIQ, ipiq, send_pasv, 1, IPIQ_STRING, IPIQ_ARG_SIZE);
106 KTR_INFO(KTR_IPIQ, ipiq, send_nbio, 2, IPIQ_STRING, IPIQ_ARG_SIZE);
107 KTR_INFO(KTR_IPIQ, ipiq, send_fail, 3, IPIQ_STRING, IPIQ_ARG_SIZE);
108 KTR_INFO(KTR_IPIQ, ipiq, receive, 4, IPIQ_STRING, IPIQ_ARG_SIZE);
109 KTR_INFO(KTR_IPIQ, ipiq, sync_start, 5, "cpumask=%08x", sizeof(cpumask_t));
110 KTR_INFO(KTR_IPIQ, ipiq, sync_add, 6, "cpumask=%08x", sizeof(cpumask_t));
111 KTR_INFO(KTR_IPIQ, ipiq, cpu_send, 7, IPIQ_STRING, IPIQ_ARG_SIZE);
112 KTR_INFO(KTR_IPIQ, ipiq, send_end, 8, IPIQ_STRING, IPIQ_ARG_SIZE);
114 #define logipiq(name, func, arg1, arg2, sgd, dgd) \
115 KTR_LOG(ipiq_ ## name, func, arg1, arg2, sgd->gd_cpuid, dgd->gd_cpuid)
116 #define logipiq2(name, arg) \
117 KTR_LOG(ipiq_ ## name, arg)
123 static int lwkt_process_ipiq_core(globaldata_t sgd, lwkt_ipiq_t ip,
124 struct intrframe *frame);
125 static void lwkt_cpusync_remote1(lwkt_cpusync_t poll);
126 static void lwkt_cpusync_remote2(lwkt_cpusync_t poll);
129 * Send a function execution request to another cpu. The request is queued
130 * on the cpu<->cpu ipiq matrix. Each cpu owns a unique ipiq FIFO for every
131 * possible target cpu. The FIFO can be written.
133 * If the FIFO fills up we have to enable interrupts to avoid an APIC
134 * deadlock and process pending IPIQs while waiting for it to empty.
135 * Otherwise we may soft-deadlock with another cpu whos FIFO is also full.
137 * We can safely bump gd_intr_nesting_level because our crit_exit() at the
138 * end will take care of any pending interrupts.
140 * The actual hardware IPI is avoided if the target cpu is already processing
141 * the queue from a prior IPI. It is possible to pipeline IPI messages
142 * very quickly between cpus due to the FIFO hysteresis.
144 * Need not be called from a critical section.
147 lwkt_send_ipiq3(globaldata_t target, ipifunc3_t func, void *arg1, int arg2)
151 struct globaldata *gd = mycpu;
153 logipiq(send_norm, func, arg1, arg2, gd, target);
156 func(arg1, arg2, NULL);
157 logipiq(send_end, func, arg1, arg2, gd, target);
161 ++gd->gd_intr_nesting_level;
163 if (gd->gd_intr_nesting_level > 20)
164 panic("lwkt_send_ipiq: TOO HEAVILY NESTED!");
166 KKASSERT(curthread->td_critcount);
168 ip = &gd->gd_ipiq[target->gd_cpuid];
171 * Do not allow the FIFO to become full. Interrupts must be physically
172 * enabled while we liveloop to avoid deadlocking the APIC.
174 if (ip->ip_windex - ip->ip_rindex > MAXCPUFIFO / 2) {
175 #if defined(__i386__)
176 unsigned int eflags = read_eflags();
177 #elif defined(__x86_64__)
178 unsigned long rflags = read_rflags();
181 if (atomic_poll_acquire_int(&ip->ip_npoll) || ipiq_optimized == 0) {
182 logipiq(cpu_send, func, arg1, arg2, gd, target);
183 cpu_send_ipiq(target->gd_cpuid);
187 while (ip->ip_windex - ip->ip_rindex > MAXCPUFIFO / 4) {
188 KKASSERT(ip->ip_windex - ip->ip_rindex != MAXCPUFIFO - 1);
191 #if defined(__i386__)
192 write_eflags(eflags);
193 #elif defined(__x86_64__)
194 write_rflags(rflags);
199 * Queue the new message
201 windex = ip->ip_windex & MAXCPUFIFO_MASK;
202 ip->ip_func[windex] = func;
203 ip->ip_arg1[windex] = arg1;
204 ip->ip_arg2[windex] = arg2;
207 --gd->gd_intr_nesting_level;
210 * signal the target cpu that there is work pending.
212 if (atomic_poll_acquire_int(&ip->ip_npoll)) {
213 logipiq(cpu_send, func, arg1, arg2, gd, target);
214 cpu_send_ipiq(target->gd_cpuid);
216 if (ipiq_optimized == 0) {
217 logipiq(cpu_send, func, arg1, arg2, gd, target);
218 cpu_send_ipiq(target->gd_cpuid);
225 logipiq(send_end, func, arg1, arg2, gd, target);
226 return(ip->ip_windex);
230 * Similar to lwkt_send_ipiq() but this function does not actually initiate
231 * the IPI to the target cpu unless the FIFO has become too full, so it is
234 * This function is used for non-critical IPI messages, such as memory
235 * deallocations. The queue will typically be flushed by the target cpu at
236 * the next clock interrupt.
238 * Need not be called from a critical section.
241 lwkt_send_ipiq3_passive(globaldata_t target, ipifunc3_t func,
242 void *arg1, int arg2)
246 struct globaldata *gd = mycpu;
248 KKASSERT(target != gd);
250 logipiq(send_pasv, func, arg1, arg2, gd, target);
251 ++gd->gd_intr_nesting_level;
253 if (gd->gd_intr_nesting_level > 20)
254 panic("lwkt_send_ipiq: TOO HEAVILY NESTED!");
256 KKASSERT(curthread->td_critcount);
259 ip = &gd->gd_ipiq[target->gd_cpuid];
262 * Do not allow the FIFO to become full. Interrupts must be physically
263 * enabled while we liveloop to avoid deadlocking the APIC.
265 if (ip->ip_windex - ip->ip_rindex > MAXCPUFIFO / 2) {
266 #if defined(__i386__)
267 unsigned int eflags = read_eflags();
268 #elif defined(__x86_64__)
269 unsigned long rflags = read_rflags();
272 if (atomic_poll_acquire_int(&ip->ip_npoll) || ipiq_optimized == 0) {
273 logipiq(cpu_send, func, arg1, arg2, gd, target);
274 cpu_send_ipiq(target->gd_cpuid);
278 while (ip->ip_windex - ip->ip_rindex > MAXCPUFIFO / 4) {
279 KKASSERT(ip->ip_windex - ip->ip_rindex != MAXCPUFIFO - 1);
282 #if defined(__i386__)
283 write_eflags(eflags);
284 #elif defined(__x86_64__)
285 write_rflags(rflags);
290 * Queue the new message
292 windex = ip->ip_windex & MAXCPUFIFO_MASK;
293 ip->ip_func[windex] = func;
294 ip->ip_arg1[windex] = arg1;
295 ip->ip_arg2[windex] = arg2;
298 --gd->gd_intr_nesting_level;
301 * Do not signal the target cpu, it will pick up the IPI when it next
302 * polls (typically on the next tick).
306 logipiq(send_end, func, arg1, arg2, gd, target);
307 return(ip->ip_windex);
311 * Send an IPI request without blocking, return 0 on success, ENOENT on
312 * failure. The actual queueing of the hardware IPI may still force us
313 * to spin and process incoming IPIs but that will eventually go away
314 * when we've gotten rid of the other general IPIs.
317 lwkt_send_ipiq3_nowait(globaldata_t target, ipifunc3_t func,
318 void *arg1, int arg2)
322 struct globaldata *gd = mycpu;
324 logipiq(send_nbio, func, arg1, arg2, gd, target);
325 KKASSERT(curthread->td_critcount);
327 func(arg1, arg2, NULL);
328 logipiq(send_end, func, arg1, arg2, gd, target);
332 ip = &gd->gd_ipiq[target->gd_cpuid];
334 if (ip->ip_windex - ip->ip_rindex >= MAXCPUFIFO * 2 / 3) {
335 logipiq(send_fail, func, arg1, arg2, gd, target);
338 windex = ip->ip_windex & MAXCPUFIFO_MASK;
339 ip->ip_func[windex] = func;
340 ip->ip_arg1[windex] = arg1;
341 ip->ip_arg2[windex] = arg2;
346 * This isn't a passive IPI, we still have to signal the target cpu.
348 if (atomic_poll_acquire_int(&ip->ip_npoll)) {
349 logipiq(cpu_send, func, arg1, arg2, gd, target);
350 cpu_send_ipiq(target->gd_cpuid);
352 if (ipiq_optimized == 0) {
353 logipiq(cpu_send, func, arg1, arg2, gd, target);
354 cpu_send_ipiq(target->gd_cpuid);
360 logipiq(send_end, func, arg1, arg2, gd, target);
365 * deprecated, used only by fast int forwarding.
368 lwkt_send_ipiq3_bycpu(int dcpu, ipifunc3_t func, void *arg1, int arg2)
370 return(lwkt_send_ipiq3(globaldata_find(dcpu), func, arg1, arg2));
374 * Send a message to several target cpus. Typically used for scheduling.
375 * The message will not be sent to stopped cpus.
378 lwkt_send_ipiq3_mask(u_int32_t mask, ipifunc3_t func, void *arg1, int arg2)
383 mask &= ~stopped_cpus;
386 lwkt_send_ipiq3(globaldata_find(cpuid), func, arg1, arg2);
387 mask &= ~(1 << cpuid);
394 * Wait for the remote cpu to finish processing a function.
396 * YYY we have to enable interrupts and process the IPIQ while waiting
397 * for it to empty or we may deadlock with another cpu. Create a CPU_*()
398 * function to do this! YYY we really should 'block' here.
400 * MUST be called from a critical section. This routine may be called
401 * from an interrupt (for example, if an interrupt wakes a foreign thread
405 lwkt_wait_ipiq(globaldata_t target, int seq)
408 int maxc = 100000000;
410 if (target != mycpu) {
411 ip = &mycpu->gd_ipiq[target->gd_cpuid];
412 if ((int)(ip->ip_xindex - seq) < 0) {
413 #if defined(__i386__)
414 unsigned int eflags = read_eflags();
415 #elif defined(__x86_64__)
416 unsigned long rflags = read_rflags();
419 while ((int)(ip->ip_xindex - seq) < 0) {
424 kprintf("LWKT_WAIT_IPIQ WARNING! %d wait %d (%d)\n", mycpu->gd_cpuid, target->gd_cpuid, ip->ip_xindex - seq);
426 panic("LWKT_WAIT_IPIQ");
428 * xindex may be modified by another cpu, use a load fence
429 * to ensure that the loop does not use a speculative value
430 * (which may improve performance).
434 #if defined(__i386__)
435 write_eflags(eflags);
436 #elif defined(__x86_64__)
437 write_rflags(rflags);
444 lwkt_seq_ipiq(globaldata_t target)
448 ip = &mycpu->gd_ipiq[target->gd_cpuid];
449 return(ip->ip_windex);
453 * Called from IPI interrupt (like a fast interrupt), which has placed
454 * us in a critical section. The MP lock may or may not be held.
455 * May also be called from doreti or splz, or be reentrantly called
456 * indirectly through the ip_func[] we run.
458 * There are two versions, one where no interrupt frame is available (when
459 * called from the send code and from splz, and one where an interrupt
460 * frame is available.
463 lwkt_process_ipiq(void)
465 globaldata_t gd = mycpu;
471 for (n = 0; n < ncpus; ++n) {
472 if (n != gd->gd_cpuid) {
473 sgd = globaldata_find(n);
476 while (lwkt_process_ipiq_core(sgd, &ip[gd->gd_cpuid], NULL))
481 if (gd->gd_cpusyncq.ip_rindex != gd->gd_cpusyncq.ip_windex) {
482 if (lwkt_process_ipiq_core(gd, &gd->gd_cpusyncq, NULL)) {
483 if (gd->gd_curthread->td_cscount == 0)
491 lwkt_process_ipiq_frame(struct intrframe *frame)
493 globaldata_t gd = mycpu;
499 for (n = 0; n < ncpus; ++n) {
500 if (n != gd->gd_cpuid) {
501 sgd = globaldata_find(n);
504 while (lwkt_process_ipiq_core(sgd, &ip[gd->gd_cpuid], frame))
509 if (gd->gd_cpusyncq.ip_rindex != gd->gd_cpusyncq.ip_windex) {
510 if (lwkt_process_ipiq_core(gd, &gd->gd_cpusyncq, frame)) {
511 if (gd->gd_curthread->td_cscount == 0)
519 lwkt_process_ipiq_core(globaldata_t sgd, lwkt_ipiq_t ip,
520 struct intrframe *frame)
522 globaldata_t mygd = mycpu;
525 ipifunc3_t copy_func;
530 * Obtain the current write index, which is modified by a remote cpu.
531 * Issue a load fence to prevent speculative reads of e.g. data written
532 * by the other cpu prior to it updating the index.
534 KKASSERT(curthread->td_critcount);
537 ++mygd->gd_intr_nesting_level;
540 * NOTE: xindex is only updated after we are sure the function has
541 * finished execution. Beware lwkt_process_ipiq() reentrancy!
542 * The function may send an IPI which may block/drain.
544 * NOTE: Due to additional IPI operations that the callback function
545 * may make, it is possible for both rindex and windex to advance and
546 * thus for rindex to advance passed our cached windex.
548 * NOTE: A memory fence is required to prevent speculative loads prior
549 * to the loading of ip_rindex. Even though stores might be
550 * ordered, loads are probably not.
552 while (wi - (ri = ip->ip_rindex) > 0) {
553 ri &= MAXCPUFIFO_MASK;
555 copy_func = ip->ip_func[ri];
556 copy_arg1 = ip->ip_arg1[ri];
557 copy_arg2 = ip->ip_arg2[ri];
559 KKASSERT((ip->ip_rindex & MAXCPUFIFO_MASK) ==
560 ((ri + 1) & MAXCPUFIFO_MASK));
561 logipiq(receive, copy_func, copy_arg1, copy_arg2, sgd, mycpu);
562 copy_func(copy_arg1, copy_arg2, frame);
564 ip->ip_xindex = ip->ip_rindex;
568 * Simulate panics during the processing of an IPI
570 if (mycpu->gd_cpuid == panic_ipiq_cpu && panic_ipiq_count) {
571 if (--panic_ipiq_count == 0) {
573 Debugger("PANIC_DEBUG");
575 panic("PANIC_DEBUG");
581 --mygd->gd_intr_nesting_level;
584 * Return non-zero if there are more IPI messages pending on this
585 * ipiq. ip_npoll is left set as long as possible to reduce the
586 * number of IPIs queued by the originating cpu, but must be cleared
587 * *BEFORE* checking windex.
589 atomic_poll_release_int(&ip->ip_npoll);
590 return(wi != ip->ip_windex);
594 lwkt_sync_ipiq(void *arg)
596 cpumask_t *cpumask = arg;
598 atomic_clear_int(cpumask, mycpu->gd_cpumask);
604 lwkt_synchronize_ipiqs(const char *wmesg)
606 cpumask_t other_cpumask;
608 other_cpumask = mycpu->gd_other_cpus & smp_active_mask;
609 lwkt_send_ipiq_mask(other_cpumask, lwkt_sync_ipiq, &other_cpumask);
611 while (other_cpumask != 0) {
612 tsleep_interlock(&other_cpumask, 0);
613 if (other_cpumask != 0)
614 tsleep(&other_cpumask, PINTERLOCKED, wmesg, 0);
621 * CPU Synchronization Support
623 * lwkt_cpusync_simple()
625 * The function is executed synchronously before return on remote cpus.
626 * A lwkt_cpusync_t pointer is passed as an argument. The data can
627 * be accessed via arg->cs_data.
629 * XXX should I just pass the data as an argument to be consistent?
633 lwkt_cpusync_simple(cpumask_t mask, cpusync_func_t func, void *data)
635 struct lwkt_cpusync cmd;
637 cmd.cs_run_func = NULL;
638 cmd.cs_fin1_func = func;
639 cmd.cs_fin2_func = NULL;
641 lwkt_cpusync_start(mask & mycpu->gd_other_cpus, &cmd);
642 if (mask & (1 << mycpu->gd_cpuid))
644 lwkt_cpusync_finish(&cmd);
648 * lwkt_cpusync_fastdata()
650 * The function is executed in tandem with return on remote cpus.
651 * The data is directly passed as an argument. Do not pass pointers to
652 * temporary storage as the storage might have
653 * gone poof by the time the target cpu executes
656 * At the moment lwkt_cpusync is declared on the stack and we must wait
657 * for all remote cpus to ack in lwkt_cpusync_finish(), but as a future
658 * optimization we should be able to put a counter in the globaldata
659 * structure (if it is not otherwise being used) and just poke it and
660 * return without waiting. XXX
663 lwkt_cpusync_fastdata(cpumask_t mask, cpusync_func2_t func, void *data)
665 struct lwkt_cpusync cmd;
667 cmd.cs_run_func = NULL;
668 cmd.cs_fin1_func = NULL;
669 cmd.cs_fin2_func = func;
671 lwkt_cpusync_start(mask & mycpu->gd_other_cpus, &cmd);
672 if (mask & (1 << mycpu->gd_cpuid))
674 lwkt_cpusync_finish(&cmd);
678 * lwkt_cpusync_start()
680 * Start synchronization with a set of target cpus, return once they are
681 * known to be in a synchronization loop. The target cpus will execute
682 * poll->cs_run_func() IN TANDEM WITH THE RETURN.
684 * XXX future: add lwkt_cpusync_start_quick() and require a call to
685 * lwkt_cpusync_add() or lwkt_cpusync_wait(), allowing the caller to
686 * potentially absorb the IPI latency doing something useful.
689 lwkt_cpusync_start(cpumask_t mask, lwkt_cpusync_t poll)
691 globaldata_t gd = mycpu;
694 poll->cs_mask = mask;
696 logipiq2(sync_start, mask & gd->gd_other_cpus);
697 poll->cs_maxcount = lwkt_send_ipiq_mask(
698 mask & gd->gd_other_cpus & smp_active_mask,
699 (ipifunc1_t)lwkt_cpusync_remote1, poll);
701 if (mask & gd->gd_cpumask) {
702 if (poll->cs_run_func)
703 poll->cs_run_func(poll);
706 if (poll->cs_maxcount) {
708 ++gd->gd_curthread->td_cscount;
709 while (poll->cs_count != poll->cs_maxcount) {
719 lwkt_cpusync_add(cpumask_t mask, lwkt_cpusync_t poll)
721 globaldata_t gd = mycpu;
726 mask &= ~poll->cs_mask;
727 poll->cs_mask |= mask;
729 logipiq2(sync_add, mask & gd->gd_other_cpus);
730 count = lwkt_send_ipiq_mask(
731 mask & gd->gd_other_cpus & smp_active_mask,
732 (ipifunc1_t)lwkt_cpusync_remote1, poll);
734 if (mask & gd->gd_cpumask) {
735 if (poll->cs_run_func)
736 poll->cs_run_func(poll);
739 poll->cs_maxcount += count;
740 if (poll->cs_maxcount) {
741 if (poll->cs_maxcount == count)
742 ++gd->gd_curthread->td_cscount;
743 while (poll->cs_count != poll->cs_maxcount) {
753 * Finish synchronization with a set of target cpus. The target cpus will
754 * execute cs_fin1_func(poll) prior to this function returning, and will
755 * execute cs_fin2_func(data) IN TANDEM WITH THIS FUNCTION'S RETURN.
757 * If cs_maxcount is non-zero then we are mastering a cpusync with one or
758 * more remote cpus and must account for it in our thread structure.
761 lwkt_cpusync_finish(lwkt_cpusync_t poll)
763 globaldata_t gd = mycpu;
766 if (poll->cs_mask & gd->gd_cpumask) {
767 if (poll->cs_fin1_func)
768 poll->cs_fin1_func(poll);
769 if (poll->cs_fin2_func)
770 poll->cs_fin2_func(poll->cs_data);
773 if (poll->cs_maxcount) {
774 while (poll->cs_count != -(poll->cs_maxcount + 1)) {
779 --gd->gd_curthread->td_cscount;
787 * helper IPI remote messaging function.
789 * Called on remote cpu when a new cpu synchronization request has been
790 * sent to us. Execute the run function and adjust cs_count, then requeue
791 * the request so we spin on it.
794 lwkt_cpusync_remote1(lwkt_cpusync_t poll)
796 atomic_add_int(&poll->cs_count, 1);
797 if (poll->cs_run_func)
798 poll->cs_run_func(poll);
799 lwkt_cpusync_remote2(poll);
803 * helper IPI remote messaging function.
805 * Poll for the originator telling us to finish. If it hasn't, requeue
806 * our request so we spin on it. When the originator requests that we
807 * finish we execute cs_fin1_func(poll) synchronously and cs_fin2_func(data)
808 * in tandem with the release.
811 lwkt_cpusync_remote2(lwkt_cpusync_t poll)
813 if (poll->cs_count < 0) {
814 cpusync_func2_t savef;
817 if (poll->cs_fin1_func)
818 poll->cs_fin1_func(poll);
819 if (poll->cs_fin2_func) {
820 savef = poll->cs_fin2_func;
821 saved = poll->cs_data;
822 atomic_add_int(&poll->cs_count, -1);
825 atomic_add_int(&poll->cs_count, -1);
828 globaldata_t gd = mycpu;
832 ip = &gd->gd_cpusyncq;
833 wi = ip->ip_windex & MAXCPUFIFO_MASK;
834 ip->ip_func[wi] = (ipifunc3_t)(ipifunc1_t)lwkt_cpusync_remote2;
835 ip->ip_arg1[wi] = poll;