Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 1 | /* |
| 2 | * Generic helpers for smp ipi calls |
| 3 | * |
| 4 | * (C) Jens Axboe <jens.axboe@oracle.com> 2008 |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 5 | */ |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 6 | #include <linux/rcupdate.h> |
Linus Torvalds | 59190f4 | 2008-07-15 14:02:33 -0700 | [diff] [blame] | 7 | #include <linux/rculist.h> |
Ingo Molnar | 641cd4c | 2009-03-13 10:47:34 +0100 | [diff] [blame] | 8 | #include <linux/kernel.h> |
Ingo Molnar | 0b13fda | 2009-02-25 16:52:11 +0100 | [diff] [blame] | 9 | #include <linux/module.h> |
| 10 | #include <linux/percpu.h> |
| 11 | #include <linux/init.h> |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 12 | #include <linux/smp.h> |
Peter Zijlstra | 8969a5e | 2009-02-25 13:59:47 +0100 | [diff] [blame] | 13 | #include <linux/cpu.h> |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 14 | |
| 15 | static DEFINE_PER_CPU(struct call_single_queue, call_single_queue); |
Peter Zijlstra | 8969a5e | 2009-02-25 13:59:47 +0100 | [diff] [blame] | 16 | |
| 17 | static struct { |
| 18 | struct list_head queue; |
| 19 | spinlock_t lock; |
Ingo Molnar | 0b13fda | 2009-02-25 16:52:11 +0100 | [diff] [blame] | 20 | } call_function __cacheline_aligned_in_smp = |
| 21 | { |
| 22 | .queue = LIST_HEAD_INIT(call_function.queue), |
| 23 | .lock = __SPIN_LOCK_UNLOCKED(call_function.lock), |
| 24 | }; |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 25 | |
| 26 | enum { |
Peter Zijlstra | 6e27563 | 2009-02-25 13:59:48 +0100 | [diff] [blame] | 27 | CSD_FLAG_LOCK = 0x01, |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 28 | }; |
| 29 | |
| 30 | struct call_function_data { |
Ingo Molnar | 0b13fda | 2009-02-25 16:52:11 +0100 | [diff] [blame] | 31 | struct call_single_data csd; |
| 32 | spinlock_t lock; |
| 33 | unsigned int refs; |
| 34 | cpumask_var_t cpumask; |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 35 | }; |
| 36 | |
| 37 | struct call_single_queue { |
Ingo Molnar | 0b13fda | 2009-02-25 16:52:11 +0100 | [diff] [blame] | 38 | struct list_head list; |
| 39 | spinlock_t lock; |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 40 | }; |
| 41 | |
Peter Zijlstra | 8969a5e | 2009-02-25 13:59:47 +0100 | [diff] [blame] | 42 | static DEFINE_PER_CPU(struct call_function_data, cfd_data) = { |
Ingo Molnar | 0b13fda | 2009-02-25 16:52:11 +0100 | [diff] [blame] | 43 | .lock = __SPIN_LOCK_UNLOCKED(cfd_data.lock), |
Peter Zijlstra | 8969a5e | 2009-02-25 13:59:47 +0100 | [diff] [blame] | 44 | }; |
| 45 | |
| 46 | static int |
| 47 | hotplug_cfd(struct notifier_block *nfb, unsigned long action, void *hcpu) |
| 48 | { |
| 49 | long cpu = (long)hcpu; |
| 50 | struct call_function_data *cfd = &per_cpu(cfd_data, cpu); |
| 51 | |
| 52 | switch (action) { |
| 53 | case CPU_UP_PREPARE: |
| 54 | case CPU_UP_PREPARE_FROZEN: |
Yinghai Lu | eaa9584 | 2009-06-06 14:51:36 -0700 | [diff] [blame] | 55 | if (!zalloc_cpumask_var_node(&cfd->cpumask, GFP_KERNEL, |
Peter Zijlstra | 8969a5e | 2009-02-25 13:59:47 +0100 | [diff] [blame] | 56 | cpu_to_node(cpu))) |
| 57 | return NOTIFY_BAD; |
| 58 | break; |
| 59 | |
Xiao Guangrong | 69dd647 | 2009-08-06 15:07:29 -0700 | [diff] [blame] | 60 | #ifdef CONFIG_HOTPLUG_CPU |
Peter Zijlstra | 8969a5e | 2009-02-25 13:59:47 +0100 | [diff] [blame] | 61 | case CPU_UP_CANCELED: |
| 62 | case CPU_UP_CANCELED_FROZEN: |
| 63 | |
| 64 | case CPU_DEAD: |
| 65 | case CPU_DEAD_FROZEN: |
| 66 | free_cpumask_var(cfd->cpumask); |
| 67 | break; |
| 68 | #endif |
| 69 | }; |
| 70 | |
| 71 | return NOTIFY_OK; |
| 72 | } |
| 73 | |
| 74 | static struct notifier_block __cpuinitdata hotplug_cfd_notifier = { |
Ingo Molnar | 0b13fda | 2009-02-25 16:52:11 +0100 | [diff] [blame] | 75 | .notifier_call = hotplug_cfd, |
Peter Zijlstra | 8969a5e | 2009-02-25 13:59:47 +0100 | [diff] [blame] | 76 | }; |
| 77 | |
Eduard - Gabriel Munteanu | 7babe8d | 2008-07-25 19:45:11 -0700 | [diff] [blame] | 78 | static int __cpuinit init_call_single_data(void) |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 79 | { |
Peter Zijlstra | 8969a5e | 2009-02-25 13:59:47 +0100 | [diff] [blame] | 80 | void *cpu = (void *)(long)smp_processor_id(); |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 81 | int i; |
| 82 | |
| 83 | for_each_possible_cpu(i) { |
| 84 | struct call_single_queue *q = &per_cpu(call_single_queue, i); |
| 85 | |
| 86 | spin_lock_init(&q->lock); |
| 87 | INIT_LIST_HEAD(&q->list); |
| 88 | } |
Peter Zijlstra | 8969a5e | 2009-02-25 13:59:47 +0100 | [diff] [blame] | 89 | |
| 90 | hotplug_cfd(&hotplug_cfd_notifier, CPU_UP_PREPARE, cpu); |
| 91 | register_cpu_notifier(&hotplug_cfd_notifier); |
| 92 | |
Eduard - Gabriel Munteanu | 7babe8d | 2008-07-25 19:45:11 -0700 | [diff] [blame] | 93 | return 0; |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 94 | } |
Eduard - Gabriel Munteanu | 7babe8d | 2008-07-25 19:45:11 -0700 | [diff] [blame] | 95 | early_initcall(init_call_single_data); |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 96 | |
Peter Zijlstra | 8969a5e | 2009-02-25 13:59:47 +0100 | [diff] [blame] | 97 | /* |
Peter Zijlstra | 8969a5e | 2009-02-25 13:59:47 +0100 | [diff] [blame] | 98 | * csd_lock/csd_unlock used to serialize access to per-cpu csd resources |
| 99 | * |
Ingo Molnar | 0b13fda | 2009-02-25 16:52:11 +0100 | [diff] [blame] | 100 | * For non-synchronous ipi calls the csd can still be in use by the |
| 101 | * previous function call. For multi-cpu calls its even more interesting |
| 102 | * as we'll have to ensure no other cpu is observing our csd. |
Peter Zijlstra | 8969a5e | 2009-02-25 13:59:47 +0100 | [diff] [blame] | 103 | */ |
Peter Zijlstra | 6e27563 | 2009-02-25 13:59:48 +0100 | [diff] [blame] | 104 | static void csd_lock_wait(struct call_single_data *data) |
Peter Zijlstra | 8969a5e | 2009-02-25 13:59:47 +0100 | [diff] [blame] | 105 | { |
| 106 | while (data->flags & CSD_FLAG_LOCK) |
| 107 | cpu_relax(); |
Peter Zijlstra | 6e27563 | 2009-02-25 13:59:48 +0100 | [diff] [blame] | 108 | } |
| 109 | |
| 110 | static void csd_lock(struct call_single_data *data) |
| 111 | { |
| 112 | csd_lock_wait(data); |
Peter Zijlstra | 8969a5e | 2009-02-25 13:59:47 +0100 | [diff] [blame] | 113 | data->flags = CSD_FLAG_LOCK; |
| 114 | |
| 115 | /* |
Ingo Molnar | 0b13fda | 2009-02-25 16:52:11 +0100 | [diff] [blame] | 116 | * prevent CPU from reordering the above assignment |
| 117 | * to ->flags with any subsequent assignments to other |
| 118 | * fields of the specified call_single_data structure: |
Peter Zijlstra | 8969a5e | 2009-02-25 13:59:47 +0100 | [diff] [blame] | 119 | */ |
Peter Zijlstra | 8969a5e | 2009-02-25 13:59:47 +0100 | [diff] [blame] | 120 | smp_mb(); |
| 121 | } |
| 122 | |
| 123 | static void csd_unlock(struct call_single_data *data) |
| 124 | { |
| 125 | WARN_ON(!(data->flags & CSD_FLAG_LOCK)); |
Ingo Molnar | 0b13fda | 2009-02-25 16:52:11 +0100 | [diff] [blame] | 126 | |
Peter Zijlstra | 8969a5e | 2009-02-25 13:59:47 +0100 | [diff] [blame] | 127 | /* |
Ingo Molnar | 0b13fda | 2009-02-25 16:52:11 +0100 | [diff] [blame] | 128 | * ensure we're all done before releasing data: |
Peter Zijlstra | 8969a5e | 2009-02-25 13:59:47 +0100 | [diff] [blame] | 129 | */ |
| 130 | smp_mb(); |
Ingo Molnar | 0b13fda | 2009-02-25 16:52:11 +0100 | [diff] [blame] | 131 | |
Peter Zijlstra | 8969a5e | 2009-02-25 13:59:47 +0100 | [diff] [blame] | 132 | data->flags &= ~CSD_FLAG_LOCK; |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 133 | } |
| 134 | |
| 135 | /* |
Ingo Molnar | 0b13fda | 2009-02-25 16:52:11 +0100 | [diff] [blame] | 136 | * Insert a previously allocated call_single_data element |
| 137 | * for execution on the given CPU. data must already have |
| 138 | * ->func, ->info, and ->flags set. |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 139 | */ |
Peter Zijlstra | 6e27563 | 2009-02-25 13:59:48 +0100 | [diff] [blame] | 140 | static |
| 141 | void generic_exec_single(int cpu, struct call_single_data *data, int wait) |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 142 | { |
| 143 | struct call_single_queue *dst = &per_cpu(call_single_queue, cpu); |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 144 | unsigned long flags; |
Peter Zijlstra | 6e27563 | 2009-02-25 13:59:48 +0100 | [diff] [blame] | 145 | int ipi; |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 146 | |
| 147 | spin_lock_irqsave(&dst->lock, flags); |
| 148 | ipi = list_empty(&dst->list); |
| 149 | list_add_tail(&data->list, &dst->list); |
| 150 | spin_unlock_irqrestore(&dst->lock, flags); |
| 151 | |
Suresh Siddha | 561920a0 | 2008-10-30 18:28:41 +0100 | [diff] [blame] | 152 | /* |
Nick Piggin | 15d0d3b | 2009-02-25 06:22:45 +0100 | [diff] [blame] | 153 | * The list addition should be visible before sending the IPI |
| 154 | * handler locks the list to pull the entry off it because of |
| 155 | * normal cache coherency rules implied by spinlocks. |
| 156 | * |
| 157 | * If IPIs can go out of order to the cache coherency protocol |
| 158 | * in an architecture, sufficient synchronisation should be added |
| 159 | * to arch code to make it appear to obey cache coherency WRT |
Ingo Molnar | 0b13fda | 2009-02-25 16:52:11 +0100 | [diff] [blame] | 160 | * locking and barrier primitives. Generic code isn't really |
| 161 | * equipped to do the right thing... |
Suresh Siddha | 561920a0 | 2008-10-30 18:28:41 +0100 | [diff] [blame] | 162 | */ |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 163 | if (ipi) |
| 164 | arch_send_call_function_single_ipi(cpu); |
| 165 | |
| 166 | if (wait) |
Peter Zijlstra | 6e27563 | 2009-02-25 13:59:48 +0100 | [diff] [blame] | 167 | csd_lock_wait(data); |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 168 | } |
| 169 | |
| 170 | /* |
| 171 | * Invoked by arch to handle an IPI for call function. Must be called with |
| 172 | * interrupts disabled. |
| 173 | */ |
| 174 | void generic_smp_call_function_interrupt(void) |
| 175 | { |
| 176 | struct call_function_data *data; |
| 177 | int cpu = get_cpu(); |
| 178 | |
| 179 | /* |
Suresh Siddha | 269c861 | 2009-08-19 18:05:35 -0700 | [diff] [blame] | 180 | * Shouldn't receive this interrupt on a cpu that is not yet online. |
| 181 | */ |
| 182 | WARN_ON_ONCE(!cpu_online(cpu)); |
| 183 | |
| 184 | /* |
Nick Piggin | 15d0d3b | 2009-02-25 06:22:45 +0100 | [diff] [blame] | 185 | * Ensure entry is visible on call_function_queue after we have |
| 186 | * entered the IPI. See comment in smp_call_function_many. |
| 187 | * If we don't have this, then we may miss an entry on the list |
| 188 | * and never get another IPI to process it. |
| 189 | */ |
| 190 | smp_mb(); |
| 191 | |
| 192 | /* |
Ingo Molnar | 0b13fda | 2009-02-25 16:52:11 +0100 | [diff] [blame] | 193 | * It's ok to use list_for_each_rcu() here even though we may |
| 194 | * delete 'pos', since list_del_rcu() doesn't clear ->next |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 195 | */ |
Peter Zijlstra | 8969a5e | 2009-02-25 13:59:47 +0100 | [diff] [blame] | 196 | list_for_each_entry_rcu(data, &call_function.queue, csd.list) { |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 197 | int refs; |
| 198 | |
Peter Zijlstra | 8969a5e | 2009-02-25 13:59:47 +0100 | [diff] [blame] | 199 | spin_lock(&data->lock); |
| 200 | if (!cpumask_test_cpu(cpu, data->cpumask)) { |
| 201 | spin_unlock(&data->lock); |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 202 | continue; |
Peter Zijlstra | 8969a5e | 2009-02-25 13:59:47 +0100 | [diff] [blame] | 203 | } |
| 204 | cpumask_clear_cpu(cpu, data->cpumask); |
| 205 | spin_unlock(&data->lock); |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 206 | |
| 207 | data->csd.func(data->csd.info); |
| 208 | |
| 209 | spin_lock(&data->lock); |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 210 | WARN_ON(data->refs == 0); |
Peter Zijlstra | 8969a5e | 2009-02-25 13:59:47 +0100 | [diff] [blame] | 211 | refs = --data->refs; |
| 212 | if (!refs) { |
| 213 | spin_lock(&call_function.lock); |
| 214 | list_del_rcu(&data->csd.list); |
| 215 | spin_unlock(&call_function.lock); |
| 216 | } |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 217 | spin_unlock(&data->lock); |
| 218 | |
| 219 | if (refs) |
| 220 | continue; |
| 221 | |
Peter Zijlstra | 8969a5e | 2009-02-25 13:59:47 +0100 | [diff] [blame] | 222 | csd_unlock(&data->csd); |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 223 | } |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 224 | |
| 225 | put_cpu(); |
| 226 | } |
| 227 | |
| 228 | /* |
Ingo Molnar | 0b13fda | 2009-02-25 16:52:11 +0100 | [diff] [blame] | 229 | * Invoked by arch to handle an IPI for call function single. Must be |
| 230 | * called from the arch with interrupts disabled. |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 231 | */ |
| 232 | void generic_smp_call_function_single_interrupt(void) |
| 233 | { |
| 234 | struct call_single_queue *q = &__get_cpu_var(call_single_queue); |
Nick Piggin | 15d0d3b | 2009-02-25 06:22:45 +0100 | [diff] [blame] | 235 | unsigned int data_flags; |
Ingo Molnar | 0b13fda | 2009-02-25 16:52:11 +0100 | [diff] [blame] | 236 | LIST_HEAD(list); |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 237 | |
Suresh Siddha | 269c861 | 2009-08-19 18:05:35 -0700 | [diff] [blame] | 238 | /* |
| 239 | * Shouldn't receive this interrupt on a cpu that is not yet online. |
| 240 | */ |
| 241 | WARN_ON_ONCE(!cpu_online(smp_processor_id())); |
| 242 | |
Nick Piggin | 15d0d3b | 2009-02-25 06:22:45 +0100 | [diff] [blame] | 243 | spin_lock(&q->lock); |
| 244 | list_replace_init(&q->list, &list); |
| 245 | spin_unlock(&q->lock); |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 246 | |
Nick Piggin | 15d0d3b | 2009-02-25 06:22:45 +0100 | [diff] [blame] | 247 | while (!list_empty(&list)) { |
| 248 | struct call_single_data *data; |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 249 | |
Ingo Molnar | 0b13fda | 2009-02-25 16:52:11 +0100 | [diff] [blame] | 250 | data = list_entry(list.next, struct call_single_data, list); |
Nick Piggin | 15d0d3b | 2009-02-25 06:22:45 +0100 | [diff] [blame] | 251 | list_del(&data->list); |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 252 | |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 253 | /* |
Ingo Molnar | 0b13fda | 2009-02-25 16:52:11 +0100 | [diff] [blame] | 254 | * 'data' can be invalid after this call if flags == 0 |
| 255 | * (when called through generic_exec_single()), |
| 256 | * so save them away before making the call: |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 257 | */ |
Nick Piggin | 15d0d3b | 2009-02-25 06:22:45 +0100 | [diff] [blame] | 258 | data_flags = data->flags; |
| 259 | |
| 260 | data->func(data->info); |
| 261 | |
Peter Zijlstra | 8969a5e | 2009-02-25 13:59:47 +0100 | [diff] [blame] | 262 | /* |
Ingo Molnar | 0b13fda | 2009-02-25 16:52:11 +0100 | [diff] [blame] | 263 | * Unlocked CSDs are valid through generic_exec_single(): |
Peter Zijlstra | 8969a5e | 2009-02-25 13:59:47 +0100 | [diff] [blame] | 264 | */ |
| 265 | if (data_flags & CSD_FLAG_LOCK) |
| 266 | csd_unlock(data); |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 267 | } |
| 268 | } |
| 269 | |
Steven Rostedt | d7240b9 | 2009-01-29 10:08:01 -0500 | [diff] [blame] | 270 | static DEFINE_PER_CPU(struct call_single_data, csd_data); |
| 271 | |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 272 | /* |
| 273 | * smp_call_function_single - Run a function on a specific CPU |
| 274 | * @func: The function to run. This must be fast and non-blocking. |
| 275 | * @info: An arbitrary pointer to pass to the function. |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 276 | * @wait: If true, wait until function has completed on other CPUs. |
| 277 | * |
| 278 | * Returns 0 on success, else a negative status code. Note that @wait |
| 279 | * will be implicitly turned on in case of allocation failures, since |
| 280 | * we fall back to on-stack allocation. |
| 281 | */ |
| 282 | int smp_call_function_single(int cpu, void (*func) (void *info), void *info, |
Jens Axboe | 8691e5a | 2008-06-06 11:18:06 +0200 | [diff] [blame] | 283 | int wait) |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 284 | { |
Peter Zijlstra | 8969a5e | 2009-02-25 13:59:47 +0100 | [diff] [blame] | 285 | struct call_single_data d = { |
| 286 | .flags = 0, |
| 287 | }; |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 288 | unsigned long flags; |
Ingo Molnar | 0b13fda | 2009-02-25 16:52:11 +0100 | [diff] [blame] | 289 | int this_cpu; |
H. Peter Anvin | f73be6d | 2008-08-25 17:07:14 -0700 | [diff] [blame] | 290 | int err = 0; |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 291 | |
Ingo Molnar | 0b13fda | 2009-02-25 16:52:11 +0100 | [diff] [blame] | 292 | /* |
| 293 | * prevent preemption and reschedule on another processor, |
| 294 | * as well as CPU removal |
| 295 | */ |
| 296 | this_cpu = get_cpu(); |
| 297 | |
Suresh Siddha | 269c861 | 2009-08-19 18:05:35 -0700 | [diff] [blame] | 298 | /* |
| 299 | * Can deadlock when called with interrupts disabled. |
| 300 | * We allow cpu's that are not yet online though, as no one else can |
| 301 | * send smp call function interrupt to this cpu and as such deadlocks |
| 302 | * can't happen. |
| 303 | */ |
| 304 | WARN_ON_ONCE(cpu_online(this_cpu) && irqs_disabled() |
| 305 | && !oops_in_progress); |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 306 | |
Ingo Molnar | 0b13fda | 2009-02-25 16:52:11 +0100 | [diff] [blame] | 307 | if (cpu == this_cpu) { |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 308 | local_irq_save(flags); |
| 309 | func(info); |
| 310 | local_irq_restore(flags); |
H. Peter Anvin | f73be6d | 2008-08-25 17:07:14 -0700 | [diff] [blame] | 311 | } else { |
Ingo Molnar | 0b13fda | 2009-02-25 16:52:11 +0100 | [diff] [blame] | 312 | if ((unsigned)cpu < nr_cpu_ids && cpu_online(cpu)) { |
| 313 | struct call_single_data *data = &d; |
| 314 | |
| 315 | if (!wait) |
| 316 | data = &__get_cpu_var(csd_data); |
| 317 | |
| 318 | csd_lock(data); |
| 319 | |
| 320 | data->func = func; |
| 321 | data->info = info; |
| 322 | generic_exec_single(cpu, data, wait); |
| 323 | } else { |
| 324 | err = -ENXIO; /* CPU not online */ |
| 325 | } |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 326 | } |
| 327 | |
| 328 | put_cpu(); |
Ingo Molnar | 0b13fda | 2009-02-25 16:52:11 +0100 | [diff] [blame] | 329 | |
H. Peter Anvin | f73be6d | 2008-08-25 17:07:14 -0700 | [diff] [blame] | 330 | return err; |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 331 | } |
| 332 | EXPORT_SYMBOL(smp_call_function_single); |
| 333 | |
| 334 | /** |
| 335 | * __smp_call_function_single(): Run a function on another CPU |
| 336 | * @cpu: The CPU to run on. |
| 337 | * @data: Pre-allocated and setup data structure |
| 338 | * |
Ingo Molnar | 0b13fda | 2009-02-25 16:52:11 +0100 | [diff] [blame] | 339 | * Like smp_call_function_single(), but allow caller to pass in a |
| 340 | * pre-allocated data structure. Useful for embedding @data inside |
| 341 | * other structures, for instance. |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 342 | */ |
Peter Zijlstra | 6e27563 | 2009-02-25 13:59:48 +0100 | [diff] [blame] | 343 | void __smp_call_function_single(int cpu, struct call_single_data *data, |
| 344 | int wait) |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 345 | { |
Peter Zijlstra | 6e27563 | 2009-02-25 13:59:48 +0100 | [diff] [blame] | 346 | csd_lock(data); |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 347 | |
Suresh Siddha | 269c861 | 2009-08-19 18:05:35 -0700 | [diff] [blame] | 348 | /* |
| 349 | * Can deadlock when called with interrupts disabled. |
| 350 | * We allow cpu's that are not yet online though, as no one else can |
| 351 | * send smp call function interrupt to this cpu and as such deadlocks |
| 352 | * can't happen. |
| 353 | */ |
| 354 | WARN_ON_ONCE(cpu_online(smp_processor_id()) && wait && irqs_disabled() |
| 355 | && !oops_in_progress); |
Peter Zijlstra | 6e27563 | 2009-02-25 13:59:48 +0100 | [diff] [blame] | 356 | |
| 357 | generic_exec_single(cpu, data, wait); |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 358 | } |
| 359 | |
Ingo Molnar | 0b13fda | 2009-02-25 16:52:11 +0100 | [diff] [blame] | 360 | /* Deprecated: shim for archs using old arch_send_call_function_ipi API. */ |
| 361 | |
Rusty Russell | ce47d97 | 2008-12-30 09:05:17 +1030 | [diff] [blame] | 362 | #ifndef arch_send_call_function_ipi_mask |
Ingo Molnar | 0b13fda | 2009-02-25 16:52:11 +0100 | [diff] [blame] | 363 | # define arch_send_call_function_ipi_mask(maskp) \ |
| 364 | arch_send_call_function_ipi(*(maskp)) |
Rusty Russell | ce47d97 | 2008-12-30 09:05:17 +1030 | [diff] [blame] | 365 | #endif |
| 366 | |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 367 | /** |
Rusty Russell | 54b11e6 | 2008-12-30 09:05:16 +1030 | [diff] [blame] | 368 | * smp_call_function_many(): Run a function on a set of other CPUs. |
| 369 | * @mask: The set of cpus to run on (only runs on online subset). |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 370 | * @func: The function to run. This must be fast and non-blocking. |
| 371 | * @info: An arbitrary pointer to pass to the function. |
Ingo Molnar | 0b13fda | 2009-02-25 16:52:11 +0100 | [diff] [blame] | 372 | * @wait: If true, wait (atomically) until function has completed |
| 373 | * on other CPUs. |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 374 | * |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 375 | * If @wait is true, then returns once @func has returned. Note that @wait |
| 376 | * will be implicitly turned on in case of allocation failures, since |
| 377 | * we fall back to on-stack allocation. |
| 378 | * |
| 379 | * You must not call this function with disabled interrupts or from a |
| 380 | * hardware interrupt handler or from a bottom half handler. Preemption |
| 381 | * must be disabled when calling this function. |
| 382 | */ |
Rusty Russell | 54b11e6 | 2008-12-30 09:05:16 +1030 | [diff] [blame] | 383 | void smp_call_function_many(const struct cpumask *mask, |
Ingo Molnar | 0b13fda | 2009-02-25 16:52:11 +0100 | [diff] [blame] | 384 | void (*func)(void *), void *info, bool wait) |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 385 | { |
Rusty Russell | 54b11e6 | 2008-12-30 09:05:16 +1030 | [diff] [blame] | 386 | struct call_function_data *data; |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 387 | unsigned long flags; |
Ingo Molnar | 0b13fda | 2009-02-25 16:52:11 +0100 | [diff] [blame] | 388 | int cpu, next_cpu, this_cpu = smp_processor_id(); |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 389 | |
Suresh Siddha | 269c861 | 2009-08-19 18:05:35 -0700 | [diff] [blame] | 390 | /* |
| 391 | * Can deadlock when called with interrupts disabled. |
| 392 | * We allow cpu's that are not yet online though, as no one else can |
| 393 | * send smp call function interrupt to this cpu and as such deadlocks |
| 394 | * can't happen. |
| 395 | */ |
| 396 | WARN_ON_ONCE(cpu_online(this_cpu) && irqs_disabled() |
| 397 | && !oops_in_progress); |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 398 | |
Ingo Molnar | 0b13fda | 2009-02-25 16:52:11 +0100 | [diff] [blame] | 399 | /* So, what's a CPU they want? Ignoring this one. */ |
Rusty Russell | 54b11e6 | 2008-12-30 09:05:16 +1030 | [diff] [blame] | 400 | cpu = cpumask_first_and(mask, cpu_online_mask); |
Ingo Molnar | 0b13fda | 2009-02-25 16:52:11 +0100 | [diff] [blame] | 401 | if (cpu == this_cpu) |
Rusty Russell | 54b11e6 | 2008-12-30 09:05:16 +1030 | [diff] [blame] | 402 | cpu = cpumask_next_and(cpu, mask, cpu_online_mask); |
Ingo Molnar | 0b13fda | 2009-02-25 16:52:11 +0100 | [diff] [blame] | 403 | |
Rusty Russell | 54b11e6 | 2008-12-30 09:05:16 +1030 | [diff] [blame] | 404 | /* No online cpus? We're done. */ |
| 405 | if (cpu >= nr_cpu_ids) |
| 406 | return; |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 407 | |
Rusty Russell | 54b11e6 | 2008-12-30 09:05:16 +1030 | [diff] [blame] | 408 | /* Do we have another CPU which isn't us? */ |
| 409 | next_cpu = cpumask_next_and(cpu, mask, cpu_online_mask); |
Ingo Molnar | 0b13fda | 2009-02-25 16:52:11 +0100 | [diff] [blame] | 410 | if (next_cpu == this_cpu) |
Rusty Russell | 54b11e6 | 2008-12-30 09:05:16 +1030 | [diff] [blame] | 411 | next_cpu = cpumask_next_and(next_cpu, mask, cpu_online_mask); |
| 412 | |
| 413 | /* Fastpath: do that cpu by itself. */ |
| 414 | if (next_cpu >= nr_cpu_ids) { |
| 415 | smp_call_function_single(cpu, func, info, wait); |
| 416 | return; |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 417 | } |
| 418 | |
Peter Zijlstra | 8969a5e | 2009-02-25 13:59:47 +0100 | [diff] [blame] | 419 | data = &__get_cpu_var(cfd_data); |
| 420 | csd_lock(&data->csd); |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 421 | |
Peter Zijlstra | 8969a5e | 2009-02-25 13:59:47 +0100 | [diff] [blame] | 422 | spin_lock_irqsave(&data->lock, flags); |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 423 | data->csd.func = func; |
| 424 | data->csd.info = info; |
Peter Zijlstra | 8969a5e | 2009-02-25 13:59:47 +0100 | [diff] [blame] | 425 | cpumask_and(data->cpumask, mask, cpu_online_mask); |
Ingo Molnar | 0b13fda | 2009-02-25 16:52:11 +0100 | [diff] [blame] | 426 | cpumask_clear_cpu(this_cpu, data->cpumask); |
Peter Zijlstra | 8969a5e | 2009-02-25 13:59:47 +0100 | [diff] [blame] | 427 | data->refs = cpumask_weight(data->cpumask); |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 428 | |
Peter Zijlstra | 8969a5e | 2009-02-25 13:59:47 +0100 | [diff] [blame] | 429 | spin_lock(&call_function.lock); |
| 430 | /* |
| 431 | * Place entry at the _HEAD_ of the list, so that any cpu still |
Ingo Molnar | 0b13fda | 2009-02-25 16:52:11 +0100 | [diff] [blame] | 432 | * observing the entry in generic_smp_call_function_interrupt() |
| 433 | * will not miss any other list entries: |
Peter Zijlstra | 8969a5e | 2009-02-25 13:59:47 +0100 | [diff] [blame] | 434 | */ |
| 435 | list_add_rcu(&data->csd.list, &call_function.queue); |
| 436 | spin_unlock(&call_function.lock); |
Ingo Molnar | 0b13fda | 2009-02-25 16:52:11 +0100 | [diff] [blame] | 437 | |
Peter Zijlstra | 8969a5e | 2009-02-25 13:59:47 +0100 | [diff] [blame] | 438 | spin_unlock_irqrestore(&data->lock, flags); |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 439 | |
Suresh Siddha | 561920a0 | 2008-10-30 18:28:41 +0100 | [diff] [blame] | 440 | /* |
| 441 | * Make the list addition visible before sending the ipi. |
Ingo Molnar | 0b13fda | 2009-02-25 16:52:11 +0100 | [diff] [blame] | 442 | * (IPIs must obey or appear to obey normal Linux cache |
| 443 | * coherency rules -- see comment in generic_exec_single). |
Suresh Siddha | 561920a0 | 2008-10-30 18:28:41 +0100 | [diff] [blame] | 444 | */ |
| 445 | smp_mb(); |
| 446 | |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 447 | /* Send a message to all CPUs in the map */ |
Peter Zijlstra | 8969a5e | 2009-02-25 13:59:47 +0100 | [diff] [blame] | 448 | arch_send_call_function_ipi_mask(data->cpumask); |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 449 | |
Ingo Molnar | 0b13fda | 2009-02-25 16:52:11 +0100 | [diff] [blame] | 450 | /* Optionally wait for the CPUs to complete */ |
Rusty Russell | 54b11e6 | 2008-12-30 09:05:16 +1030 | [diff] [blame] | 451 | if (wait) |
Peter Zijlstra | 6e27563 | 2009-02-25 13:59:48 +0100 | [diff] [blame] | 452 | csd_lock_wait(&data->csd); |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 453 | } |
Rusty Russell | 54b11e6 | 2008-12-30 09:05:16 +1030 | [diff] [blame] | 454 | EXPORT_SYMBOL(smp_call_function_many); |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 455 | |
| 456 | /** |
| 457 | * smp_call_function(): Run a function on all other CPUs. |
| 458 | * @func: The function to run. This must be fast and non-blocking. |
| 459 | * @info: An arbitrary pointer to pass to the function. |
Ingo Molnar | 0b13fda | 2009-02-25 16:52:11 +0100 | [diff] [blame] | 460 | * @wait: If true, wait (atomically) until function has completed |
| 461 | * on other CPUs. |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 462 | * |
Rusty Russell | 54b11e6 | 2008-12-30 09:05:16 +1030 | [diff] [blame] | 463 | * Returns 0. |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 464 | * |
| 465 | * If @wait is true, then returns once @func has returned; otherwise |
| 466 | * it returns just before the target cpu calls @func. In case of allocation |
| 467 | * failure, @wait will be implicitly turned on. |
| 468 | * |
| 469 | * You must not call this function with disabled interrupts or from a |
| 470 | * hardware interrupt handler or from a bottom half handler. |
| 471 | */ |
Jens Axboe | 8691e5a | 2008-06-06 11:18:06 +0200 | [diff] [blame] | 472 | int smp_call_function(void (*func)(void *), void *info, int wait) |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 473 | { |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 474 | preempt_disable(); |
Rusty Russell | 54b11e6 | 2008-12-30 09:05:16 +1030 | [diff] [blame] | 475 | smp_call_function_many(cpu_online_mask, func, info, wait); |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 476 | preempt_enable(); |
Ingo Molnar | 0b13fda | 2009-02-25 16:52:11 +0100 | [diff] [blame] | 477 | |
Rusty Russell | 54b11e6 | 2008-12-30 09:05:16 +1030 | [diff] [blame] | 478 | return 0; |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 479 | } |
| 480 | EXPORT_SYMBOL(smp_call_function); |
| 481 | |
| 482 | void ipi_call_lock(void) |
| 483 | { |
Peter Zijlstra | 8969a5e | 2009-02-25 13:59:47 +0100 | [diff] [blame] | 484 | spin_lock(&call_function.lock); |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 485 | } |
| 486 | |
| 487 | void ipi_call_unlock(void) |
| 488 | { |
Peter Zijlstra | 8969a5e | 2009-02-25 13:59:47 +0100 | [diff] [blame] | 489 | spin_unlock(&call_function.lock); |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 490 | } |
| 491 | |
| 492 | void ipi_call_lock_irq(void) |
| 493 | { |
Peter Zijlstra | 8969a5e | 2009-02-25 13:59:47 +0100 | [diff] [blame] | 494 | spin_lock_irq(&call_function.lock); |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 495 | } |
| 496 | |
| 497 | void ipi_call_unlock_irq(void) |
| 498 | { |
Peter Zijlstra | 8969a5e | 2009-02-25 13:59:47 +0100 | [diff] [blame] | 499 | spin_unlock_irq(&call_function.lock); |
Jens Axboe | 3d44223 | 2008-06-26 11:21:34 +0200 | [diff] [blame] | 500 | } |