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
34 * $DragonFly: src/sys/kern/lwkt_token.c,v 1.29 2006/12/27 06:51:47 dillon Exp $
39 #include <sys/param.h>
40 #include <sys/systm.h>
41 #include <sys/kernel.h>
43 #include <sys/rtprio.h>
44 #include <sys/queue.h>
45 #include <sys/sysctl.h>
47 #include <sys/kthread.h>
48 #include <machine/cpu.h>
51 #include <sys/spinlock.h>
53 #include <sys/thread2.h>
54 #include <sys/spinlock2.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>
66 #include <machine/stdarg.h>
67 #include <machine/smp.h>
71 #include <sys/stdint.h>
72 #include <libcaps/thread.h>
73 #include <sys/thread.h>
74 #include <sys/msgport.h>
75 #include <sys/errno.h>
76 #include <libcaps/globaldata.h>
77 #include <machine/cpufunc.h>
78 #include <sys/thread2.h>
79 #include <sys/msgport2.h>
83 #include <machine/lock.h>
84 #include <machine/cpu.h>
88 #ifndef LWKT_NUM_POOL_TOKENS
89 #define LWKT_NUM_POOL_TOKENS 1024 /* power of 2 */
91 #define LWKT_MASK_POOL_TOKENS (LWKT_NUM_POOL_TOKENS - 1)
94 static int token_debug = 0;
97 static lwkt_token pool_tokens[LWKT_NUM_POOL_TOKENS];
99 #define TOKEN_STRING "REF=%p TOK=%p TD=%p"
100 #define CONTENDED_STRING "REF=%p TOK=%p TD=%p (contention started)"
101 #define UNCONTENDED_STRING "REF=%p TOK=%p TD=%p (contention stopped)"
102 #if !defined(KTR_TOKENS)
103 #define KTR_TOKENS KTR_ALL
106 KTR_INFO_MASTER(tokens);
107 KTR_INFO(KTR_TOKENS, tokens, try, 0, TOKEN_STRING, sizeof(void *) * 3);
108 KTR_INFO(KTR_TOKENS, tokens, get, 1, TOKEN_STRING, sizeof(void *) * 3);
109 KTR_INFO(KTR_TOKENS, tokens, release, 2, TOKEN_STRING, sizeof(void *) * 3);
111 KTR_INFO(KTR_TOKENS, tokens, remote, 3, TOKEN_STRING, sizeof(void *) * 3);
112 KTR_INFO(KTR_TOKENS, tokens, reqremote, 4, TOKEN_STRING, sizeof(void *) * 3);
113 KTR_INFO(KTR_TOKENS, tokens, reqfail, 5, TOKEN_STRING, sizeof(void *) * 3);
114 KTR_INFO(KTR_TOKENS, tokens, drain, 6, TOKEN_STRING, sizeof(void *) * 3);
115 KTR_INFO(KTR_TOKENS, tokens, contention_start, 7, CONTENDED_STRING, sizeof(void *) * 3);
116 KTR_INFO(KTR_TOKENS, tokens, contention_stop, 7, UNCONTENDED_STRING, sizeof(void *) * 3);
119 #define logtoken(name, ref) \
120 KTR_LOG(tokens_ ## name, ref, ref->tr_tok, curthread)
125 SYSCTL_INT(_lwkt, OID_AUTO, token_debug, CTLFLAG_RW, &token_debug, 0, "");
133 * Obtain all the tokens required by the specified thread on the current
134 * cpu, return 0 on failure and non-zero on success.
136 * NOTE: This code does not work with UP 'degenerate' spinlocks. SMP only.
138 * The preemption code will not allow a target thread holding spinlocks to
139 * preempt the current thread so we do not have to implement this for UP.
142 lwkt_getalltokens(thread_t td)
148 for (refs = td->td_toks; refs; refs = refs->tr_next) {
149 KKASSERT(refs->tr_state == 0);
151 if (tok->t_owner != td) {
152 if (spin_trylock_wr(&tok->t_spinlock) == 0) {
154 * Release the partial list of tokens obtained and return
157 for (undo = td->td_toks; undo != refs; undo = undo->tr_next) {
160 if (--tok->t_count == 0) {
162 spin_unlock_wr(&tok->t_spinlock);
168 KKASSERT(tok->t_count == 0);
177 * Release all tokens owned by the specified thread on the current cpu.
180 lwkt_relalltokens(thread_t td)
185 for (scan = td->td_toks; scan; scan = scan->tr_next) {
186 if (scan->tr_state) {
189 KKASSERT(tok->t_owner == td && tok->t_count > 0);
190 if (--tok->t_count == 0) {
192 spin_unlock_wr(&tok->t_spinlock);
201 * Acquire a serializing token. This routine can block.
203 * On SMP systems we track ownership and a per-owner counter. Tokens are
204 * released when a thread switches out and reacquired when a thread
205 * switches back in. On UP systems we track a global counter for debugging
206 * but otherwise the only issue we have is if a preempting thread wants a
207 * token that is being held by the preempted thread.
211 _lwkt_gettokref(lwkt_tokref_t ref)
219 KKASSERT(mycpu->gd_intr_nesting_level == 0);
224 * Link the tokref to the thread's list
226 ref->tr_next = td->td_toks;
232 * Gain ownership of the token's spinlock, SMP version.
234 if (tok->t_owner != td) {
235 if (spin_trylock_wr(&tok->t_spinlock) == 0) {
239 KKASSERT(tok->t_owner == NULL && tok->t_count == 0);
245 * Gain ownership of the token, UP version. All we have to do
246 * is check the token if we are preempting someone owning the
247 * same token. If we are, we yield the cpu back to the originator
248 * and we will get rescheduled as non-preemptive.
250 while ((td = td->td_preempted) != NULL) {
251 for (scan = td->td_toks; scan; scan = scan->tr_next) {
252 if (scan->tr_tok == tok) {
258 /* NOTE: 'td' invalid after loop */
259 ++tok->t_globalcount;
266 _lwkt_trytokref(lwkt_tokref_t ref)
274 KKASSERT(mycpu->gd_intr_nesting_level == 0);
279 * Link the tokref to the thread's list
281 ref->tr_next = td->td_toks;
287 * Gain ownership of the token's spinlock, SMP version.
289 if (tok->t_owner != td) {
290 if (spin_trylock_wr(&tok->t_spinlock) == 0) {
291 td->td_toks = ref->tr_next;
294 KKASSERT(tok->t_owner == NULL && tok->t_count == 0);
300 * Gain ownership of the token, UP version. All we have to do
301 * is check the token if we are preempting someone owning the
302 * same token. If we are, we yield the cpu back to the originator
303 * and we will get rescheduled as non-preemptive.
305 while ((td = td->td_preempted) != NULL) {
306 for (scan = td->td_toks; scan; scan = scan->tr_next) {
307 if (scan->tr_tok == tok) {
308 td->td_toks = ref->tr_next;
313 /* NOTE: 'td' invalid after loop */
314 ++tok->t_globalcount;
321 lwkt_gettoken(lwkt_tokref_t ref, lwkt_token_t tok)
323 lwkt_tokref_init(ref, tok);
325 _lwkt_gettokref(ref);
329 lwkt_gettokref(lwkt_tokref_t ref)
332 _lwkt_gettokref(ref);
336 lwkt_trytoken(lwkt_tokref_t ref, lwkt_token_t tok)
338 lwkt_tokref_init(ref, tok);
340 return(_lwkt_trytokref(ref));
344 lwkt_trytokref(lwkt_tokref_t ref)
347 return(_lwkt_trytokref(ref));
351 * Release a serializing token
354 lwkt_reltoken(lwkt_tokref *ref)
356 struct lwkt_tokref **scanp;
364 KKASSERT(ref->tr_state == 1 && tok->t_owner == td && tok->t_count > 0);
366 KKASSERT(ref->tr_state == 1 && tok->t_globalcount > 0);
369 for (scanp = &td->td_toks; *scanp != ref; scanp = &((*scanp)->tr_next))
371 *scanp = ref->tr_next;
375 if (--tok->t_count == 0) {
377 spin_unlock_wr(&tok->t_spinlock);
380 --tok->t_globalcount;
382 logtoken(release, ref);
386 * Pool tokens are used to provide a type-stable serializing token
387 * pointer that does not race against disappearing data structures.
389 * This routine is called in early boot just after we setup the BSP's
390 * globaldata structure.
393 lwkt_token_pool_init(void)
397 for (i = 0; i < LWKT_NUM_POOL_TOKENS; ++i)
398 lwkt_token_init(&pool_tokens[i]);
402 lwkt_token_pool_get(void *ptraddr)
406 i = ((int)(intptr_t)ptraddr >> 2) ^ ((int)(intptr_t)ptraddr >> 12);
407 return(&pool_tokens[i & LWKT_MASK_POOL_TOKENS]);
411 * Initialize the owner and release-to cpu to the current cpu
412 * and reset the generation count.
415 lwkt_token_init(lwkt_token_t tok)
418 spin_init(&tok->t_spinlock);
422 tok->t_globalcount = 0;
427 lwkt_token_uninit(lwkt_token_t tok)