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1 | /* |
1 | /* |
2 | * Copyright (c) 2007 Jan Hudecek |
2 | * Copyright (c) 2007 Jan Hudecek |
3 | * Copyright (c) 2006 Jakub Jermar |
3 | * Copyright (c) 2006 Jakub Jermar |
4 | * All rights reserved. |
4 | * All rights reserved. |
5 | * |
5 | * |
6 | * Redistribution and use in source and binary forms, with or without |
6 | * Redistribution and use in source and binary forms, with or without |
7 | * modification, are permitted provided that the following conditions |
7 | * modification, are permitted provided that the following conditions |
8 | * are met: |
8 | * are met: |
9 | * |
9 | * |
10 | * - Redistributions of source code must retain the above copyright |
10 | * - Redistributions of source code must retain the above copyright |
11 | * notice, this list of conditions and the following disclaimer. |
11 | * notice, this list of conditions and the following disclaimer. |
12 | * - Redistributions in binary form must reproduce the above copyright |
12 | * - Redistributions in binary form must reproduce the above copyright |
13 | * notice, this list of conditions and the following disclaimer in the |
13 | * notice, this list of conditions and the following disclaimer in the |
14 | * documentation and/or other materials provided with the distribution. |
14 | * documentation and/or other materials provided with the distribution. |
15 | * - The name of the author may not be used to endorse or promote products |
15 | * - The name of the author may not be used to endorse or promote products |
16 | * derived from this software without specific prior written permission. |
16 | * derived from this software without specific prior written permission. |
17 | * |
17 | * |
18 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
18 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
19 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
19 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
20 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
20 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
21 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
21 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
22 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
22 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
23 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
23 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
24 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
24 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
25 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
25 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
26 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
26 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
27 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
27 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
28 | */ |
28 | */ |
29 | /** @addtogroup sync |
29 | /** @addtogroup sync |
30 | * @{ |
30 | * @{ |
31 | */ |
31 | */ |
32 | /** @file |
32 | /** @file |
33 | */ |
33 | */ |
34 | 34 | ||
35 | #include <synch/rcu.h> |
35 | #include <synch/rcu.h> |
36 | #include <synch/waitq.h> |
36 | #include <synch/waitq.h> |
37 | #include <arch.h> |
37 | #include <arch.h> |
38 | #include <config.h> |
38 | #include <config.h> |
39 | #include <arch/types.h> |
39 | #include <arch/types.h> |
40 | #include <proc/tasklet.h> |
40 | #include <proc/tasklet.h> |
41 | #include <synch/spinlock.h> |
41 | #include <synch/spinlock.h> |
42 | #include <time/delay.h> |
42 | #include <time/delay.h> |
43 | #include <panic.h> |
43 | #include <panic.h> |
44 | #include <print.h> |
44 | #include <print.h> |
45 | 45 | ||
46 | 46 | ||
47 | 47 | ||
48 | 48 | ||
49 | typedef struct { |
49 | typedef struct { |
50 | #ifdef CONFIG_SMP |
50 | #ifdef CONFIG_SMP |
51 | bool* cpu_mask; |
51 | bool* cpu_mask; |
52 | #endif |
52 | #endif |
53 | rcu_callback_list_t* next_batch, *current_batch, *done_batch; |
53 | rcu_callback_list_t* next_batch, *current_batch, *done_batch; |
54 | } rcu_global_t; |
54 | } rcu_global_t; |
55 | 55 | ||
56 | /** An array of structures holding the callbacks and the progress of QS for each CPU*/ |
56 | /** An array of structures holding the callbacks and the progress of QS for each CPU*/ |
57 | rcu_global_t* rcu_global=NULL; |
57 | rcu_global_t* rcu_global=NULL; |
58 | /** reference to the RCU tasklet, for scheduling it */ |
58 | /** reference to the RCU tasklet, for scheduling it */ |
59 | tasklet_descriptor_t* rcu_tasklet_desc; |
59 | tasklet_descriptor_t* rcu_tasklet_desc; |
60 | 60 | ||
61 | 61 | ||
62 | /** |
62 | /** |
63 | * Initializes data structures needed for RCU |
63 | * Initializes data structures needed for RCU |
64 | */ |
64 | */ |
65 | void rcu_init(void) |
65 | void rcu_init(void) |
66 | { |
66 | { |
67 | #ifdef CONFIG_SMP |
67 | #ifdef CONFIG_SMP |
68 | int i,j; |
68 | int i,j; |
69 | #endif |
69 | #endif |
70 | 70 | ||
71 | rcu_global = malloc(sizeof(rcu_global_t)*(config.cpu_count),0); |
71 | rcu_global = malloc(sizeof(rcu_global_t)*(config.cpu_count),0); |
72 | rcu_tasklet_desc = tasklet_register(&rcu_tasklet, NULL); |
72 | rcu_tasklet_desc = tasklet_register(&rcu_tasklet, NULL); |
73 | 73 | ||
74 | #ifdef CONFIG_SMP |
74 | #ifdef CONFIG_SMP |
75 | /* |
75 | /* |
76 | * Note: I allocate the array for a case when every CPU connected will be active |
76 | * Note: I allocate the array for a case when every CPU connected will be active |
77 | * In a case when there will be some inactive CPUs, I will use just the first cells. |
77 | * In a case when there will be some inactive CPUs, I will use just the first cells. |
78 | */ |
78 | */ |
79 | for (i=0;i<config.cpu_count;i++) { |
79 | for (i=0;i<config.cpu_count;i++) { |
80 | rcu_global[i].done_batch = NULL; |
80 | rcu_global[i].done_batch = NULL; |
81 | rcu_global[i].current_batch = NULL; |
81 | rcu_global[i].current_batch = NULL; |
82 | rcu_global[i].next_batch = NULL; |
82 | rcu_global[i].next_batch = NULL; |
83 | rcu_global[i].cpu_mask = malloc(sizeof(bool)*config.cpu_count,0); |
83 | rcu_global[i].cpu_mask = malloc(sizeof(bool)*config.cpu_count,0); |
84 | for (j=0;j<config.cpu_count;j++) { |
84 | for (j=0;j<config.cpu_count;j++) { |
85 | rcu_global[i].cpu_mask[j]=false; |
85 | rcu_global[i].cpu_mask[j]=false; |
86 | } |
86 | } |
87 | } |
87 | } |
88 | #else |
88 | #else |
89 | rcu_global[CPU->id].done_batch = NULL; |
89 | rcu_global[CPU->id].done_batch = NULL; |
90 | rcu_global[CPU->id].current_batch = NULL; |
90 | rcu_global[CPU->id].current_batch = NULL; |
91 | rcu_global[CPU->id].next_batch = NULL; |
91 | rcu_global[CPU->id].next_batch = NULL; |
92 | #endif |
92 | #endif |
93 | } |
93 | } |
94 | 94 | ||
95 | 95 | ||
96 | /** |
96 | /** |
97 | * Blocks until the grace period elapses |
97 | * Blocks until the grace period elapses |
98 | */ |
98 | */ |
99 | void rcu_synchronize(void) |
99 | void rcu_synchronize(void) |
100 | { |
100 | { |
101 | #ifdef CONFIG_SMP |
101 | #ifdef CONFIG_SMP |
102 | waitq_t wq; |
102 | waitq_t wq; |
103 | waitq_initialize(&wq); |
103 | waitq_initialize(&wq); |
104 | rcu_sync_callback(&rcu_synchronize_callback_function, &wq); |
104 | rcu_sync_callback_normal_alloc(&rcu_synchronize_callback_function, &wq); |
105 | //sleep until the end of the grace period |
105 | //sleep until the end of the grace period |
106 | waitq_sleep(&wq); |
106 | waitq_sleep(&wq); |
107 | #endif |
107 | #endif |
108 | } |
108 | } |
109 | 109 | ||
110 | #ifdef CONFIG_SMP |
110 | #ifdef CONFIG_SMP |
111 | /** |
111 | /** |
112 | * Just a wakeup for waking up rcu_synchronize when the grace period has elapsed |
112 | * Just a wakeup for waking up rcu_synchronize when the grace period has elapsed |
113 | */ |
113 | */ |
114 | void rcu_synchronize_callback_function(void* waitq) |
114 | void rcu_synchronize_callback_function(void* waitq) |
115 | { |
115 | { |
116 | waitq_wakeup(((waitq_t*)waitq), WAKEUP_ALL); |
116 | waitq_wakeup(((waitq_t*)waitq), WAKEUP_ALL); |
117 | } |
117 | } |
118 | #endif |
118 | #endif |
119 | 119 | ||
120 | 120 | ||
121 | /** |
121 | /** |
122 | * appends this callback func to the queue of waiting callbacks, the rest |
122 | * appends this callback func to the queue of waiting callbacks, the rest |
123 | * is handled in rcu_run_callbacks and in the tasklet. This is a lock free variant, |
123 | * is handled in rcu_run_callbacks and in the tasklet. This is a lock free variant, |
124 | * which must be supplied with a preallocated rcu_callback_list_t structure |
124 | * which must be supplied with a preallocated rcu_callback_list_t structure |
125 | */ |
125 | */ |
126 | void rcu_sync_callback_custom_alloc(void (*func)(void* data), void* data, rcu_callback_list_t* rd) |
126 | void rcu_sync_callback(void (*func)(void* data), void* data, rcu_callback_list_t* rd) |
127 | { |
127 | { |
128 | #ifndef CONFIG_SMP |
128 | #ifndef CONFIG_SMP |
129 | func(data); |
129 | func(data); |
130 | #else |
130 | #else |
131 | 131 | ||
132 | ipl_t ipl; |
132 | ipl_t ipl; |
133 | rd->func = func; |
133 | rd->func = func; |
134 | rd->data = data; |
134 | rd->data = data; |
135 | 135 | ||
136 | ipl = interrupts_disable(); |
136 | ipl = interrupts_disable(); |
137 | //append to the list of callbacks waiting for their batch to begin |
137 | //append to the list of callbacks waiting for their batch to begin |
138 | rd->next = rcu_global[CPU->id].next_batch; |
138 | rd->next = rcu_global[CPU->id].next_batch; |
139 | rcu_global[CPU->id].next_batch = rd; |
139 | rcu_global[CPU->id].next_batch = rd; |
140 | interrupts_restore(ipl); |
140 | interrupts_restore(ipl); |
141 | 141 | ||
142 | rcu_passQS(); |
142 | rcu_passQS(); |
143 | #endif |
143 | #endif |
144 | } |
144 | } |
145 | 145 | ||
146 | /** |
146 | /** |
147 | * RCU tasklet, tests passing through QSs, moves from current to done |
147 | * RCU tasklet, tests passing through QSs, moves from current to done |
148 | */ |
148 | */ |
149 | void rcu_tasklet(void* data) |
149 | void rcu_tasklet(void* data) |
150 | { |
150 | { |
151 | rcu_callback_list_t* rd; |
151 | rcu_callback_list_t* rd; |
152 | bool passed_all_QS; |
152 | bool passed_all_QS; |
153 | #ifdef CONFIG_SMP |
153 | #ifdef CONFIG_SMP |
154 | int i; |
154 | int i; |
155 | #endif |
155 | #endif |
156 | ipl_t ipl; |
156 | ipl_t ipl; |
157 | 157 | ||
158 | ipl = interrupts_disable(); |
158 | ipl = interrupts_disable(); |
159 | 159 | ||
160 | rcu_passQS(); |
160 | rcu_passQS(); |
161 | passed_all_QS = true; |
161 | passed_all_QS = true; |
162 | #ifdef CONFIG_SMP |
162 | #ifdef CONFIG_SMP |
163 | //check whether all CPUs have passed through QS |
163 | //check whether all CPUs have passed through QS |
164 | for (i = 0; i < config.cpu_active; i++) |
164 | for (i = 0; i < config.cpu_active; i++) |
165 | passed_all_QS &= rcu_global[CPU->id].cpu_mask[i]; |
165 | passed_all_QS &= rcu_global[CPU->id].cpu_mask[i]; |
166 | #endif |
166 | #endif |
167 | if (passed_all_QS) { |
167 | if (passed_all_QS) { |
168 | //all CPUs have passed through QS -> grace period is over, we can schedule the call to RCU callback |
168 | //all CPUs have passed through QS -> grace period is over, we can schedule the call to RCU callback |
169 | if (rcu_global[CPU->id].done_batch) { |
169 | if (rcu_global[CPU->id].done_batch) { |
170 | rd = rcu_global[CPU->id].done_batch; |
170 | rd = rcu_global[CPU->id].done_batch; |
171 | while (rd->next) rd = rd->next; |
171 | while (rd->next) rd = rd->next; |
172 | //append the current list to done list |
172 | //append the current list to done list |
173 | rd->next = rcu_global[CPU->id].current_batch; |
173 | rd->next = rcu_global[CPU->id].current_batch; |
174 | } else |
174 | } else |
175 | rcu_global[CPU->id].done_batch = rcu_global[CPU->id].current_batch; |
175 | rcu_global[CPU->id].done_batch = rcu_global[CPU->id].current_batch; |
176 | rcu_global[CPU->id].current_batch = NULL; |
176 | rcu_global[CPU->id].current_batch = NULL; |
177 | } |
177 | } |
178 | interrupts_restore(ipl); |
178 | interrupts_restore(ipl); |
179 | } |
179 | } |
180 | 180 | ||
181 | 181 | ||
182 | /** |
182 | /** |
183 | * This function indicates that the current CPU has gone through the quiescent state |
183 | * This function indicates that the current CPU has gone through the quiescent state |
184 | */ |
184 | */ |
185 | void rcu_passQS(void) |
185 | void rcu_passQS(void) |
186 | { |
186 | { |
187 | #ifdef CONFIG_SMP |
187 | #ifdef CONFIG_SMP |
188 | int i; |
188 | int i; |
189 | for (i=0;i<config.cpu_active;i++) |
189 | for (i=0;i<config.cpu_active;i++) |
190 | //on all CPUs indicate that this CPU has gone through QS |
190 | //on all CPUs indicate that this CPU has gone through QS |
191 | rcu_global[i].cpu_mask[CPU->id]=true; |
191 | rcu_global[i].cpu_mask[CPU->id]=true; |
192 | #endif |
192 | #endif |
193 | } |
193 | } |
194 | 194 | ||
195 | 195 | ||
196 | /** |
196 | /** |
197 | * Moves RCUs from next to current, schedules RCU tasklet, calls the callbacks, frees the rcu_callback_list_t |
197 | * Moves RCUs from next to current, schedules RCU tasklet, calls the callbacks, frees the rcu_callback_list_t |
198 | */ |
198 | */ |
199 | void rcu_run_callbacks(void) |
199 | void rcu_run_callbacks(void) |
200 | { |
200 | { |
201 | rcu_callback_list_t* rd, *rd2; |
201 | rcu_callback_list_t* rd, *rd2; |
202 | int i; |
202 | int i; |
203 | ipl_t ipl; |
203 | ipl_t ipl; |
204 | 204 | ||
205 | ipl = interrupts_disable(); |
205 | ipl = interrupts_disable(); |
206 | if (rcu_global[CPU->id].next_batch) { |
206 | if (rcu_global[CPU->id].next_batch) { |
207 | //we cannot append to the current list because callbacks from next batch |
207 | //we cannot append to the current list because callbacks from next batch |
208 | //haven't passed the QSs |
208 | //haven't passed the QSs |
209 | if (rcu_global[CPU->id].current_batch == NULL) { |
209 | if (rcu_global[CPU->id].current_batch == NULL) { |
210 | rcu_global[CPU->id].current_batch = rcu_global[CPU->id].next_batch; |
210 | rcu_global[CPU->id].current_batch = rcu_global[CPU->id].next_batch; |
211 | rcu_global[CPU->id].next_batch = NULL; |
211 | rcu_global[CPU->id].next_batch = NULL; |
212 | #ifdef CONFIG_SMP |
212 | #ifdef CONFIG_SMP |
213 | //initialize our CPU mask |
213 | //initialize our CPU mask |
214 | for (i=0;i<config.cpu_active;i++) |
214 | for (i=0;i<config.cpu_active;i++) |
215 | rcu_global[CPU->id].cpu_mask[i]=false; |
215 | rcu_global[CPU->id].cpu_mask[i]=false; |
216 | #endif |
216 | #endif |
217 | //schedule tasklet for all CPUs |
217 | //schedule tasklet for all CPUs |
218 | for (i=0;i<config.cpu_active;i++) { |
218 | for (i=0;i<config.cpu_active;i++) { |
219 | tasklet_schedule_SMP(rcu_tasklet_desc, i); |
219 | tasklet_schedule_SMP(rcu_tasklet_desc, i); |
220 | } |
220 | } |
221 | } |
221 | } |
222 | } |
222 | } |
223 | //this CPU has passed QS |
223 | //this CPU has passed QS |
224 | rcu_passQS(); |
224 | rcu_passQS(); |
225 | if (rcu_global[CPU->id].done_batch) { |
225 | if (rcu_global[CPU->id].done_batch) { |
226 | rd = rcu_global[CPU->id].done_batch; |
226 | rd = rcu_global[CPU->id].done_batch; |
227 | rcu_global[CPU->id].done_batch = NULL; |
227 | rcu_global[CPU->id].done_batch = NULL; |
228 | interrupts_restore(ipl); |
228 | interrupts_restore(ipl); |
229 | while (rd) { |
229 | while (rd) { |
230 | //call the callback |
230 | //call the callback |
231 | rd->func(rd->data); |
231 | rd->func(rd->data); |
232 | rd2 = rd->next; |
232 | rd2 = rd->next; |
233 | //free the structure |
233 | //free the structure |
234 | free(rd); |
234 | free(rd); |
235 | rd = rd2; |
235 | rd = rd2; |
236 | } |
236 | } |
237 | } |
237 | } |
238 | else |
238 | else |
239 | interrupts_restore(ipl); |
239 | interrupts_restore(ipl); |
240 | } |
240 | } |
241 | 241 | ||
242 | 242 | ||
- | 243 | /** |
|
- | 244 | * Generic callback for RCU, frees @paramref pointer |
|
- | 245 | * @param pointer |
|
- | 246 | */ |
|
- | 247 | void rcu_callback_free(void* pointer) |
|
- | 248 | { |
|
- | 249 | free(pointer); |
|
- | 250 | } |
|
- | 251 | ||
243 | 252 |