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authorIngo Molnar <mingo@elte.hu>2009-04-08 11:02:50 -0400
committerIngo Molnar <mingo@elte.hu>2009-04-08 11:02:57 -0400
commitff96e612cba32510e263e17b213235fe5746397e (patch)
treea8df57d76b10e0901a4fb76cd2987eb9826a560a /kernel/softlockup.c
parentcd84a42f315e50edd454c27a3da3951ccd3d735a (diff)
parent577c9c456f0e1371cbade38eaf91ae8e8a308555 (diff)
Merge commit 'v2.6.30-rc1' into core/urgent
Merge reason: need latest upstream to queue up dependent fix Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/softlockup.c')
-rw-r--r--kernel/softlockup.c100
1 files changed, 0 insertions, 100 deletions
diff --git a/kernel/softlockup.c b/kernel/softlockup.c
index 85d5a2455103..88796c330838 100644
--- a/kernel/softlockup.c
+++ b/kernel/softlockup.c
@@ -166,97 +166,11 @@ void softlockup_tick(void)
166} 166}
167 167
168/* 168/*
169 * Have a reasonable limit on the number of tasks checked:
170 */
171unsigned long __read_mostly sysctl_hung_task_check_count = 1024;
172
173/*
174 * Zero means infinite timeout - no checking done:
175 */
176unsigned long __read_mostly sysctl_hung_task_timeout_secs = 480;
177
178unsigned long __read_mostly sysctl_hung_task_warnings = 10;
179
180/*
181 * Only do the hung-tasks check on one CPU:
182 */
183static int check_cpu __read_mostly = -1;
184
185static void check_hung_task(struct task_struct *t, unsigned long now)
186{
187 unsigned long switch_count = t->nvcsw + t->nivcsw;
188
189 if (t->flags & PF_FROZEN)
190 return;
191
192 if (switch_count != t->last_switch_count || !t->last_switch_timestamp) {
193 t->last_switch_count = switch_count;
194 t->last_switch_timestamp = now;
195 return;
196 }
197 if ((long)(now - t->last_switch_timestamp) <
198 sysctl_hung_task_timeout_secs)
199 return;
200 if (!sysctl_hung_task_warnings)
201 return;
202 sysctl_hung_task_warnings--;
203
204 /*
205 * Ok, the task did not get scheduled for more than 2 minutes,
206 * complain:
207 */
208 printk(KERN_ERR "INFO: task %s:%d blocked for more than "
209 "%ld seconds.\n", t->comm, t->pid,
210 sysctl_hung_task_timeout_secs);
211 printk(KERN_ERR "\"echo 0 > /proc/sys/kernel/hung_task_timeout_secs\""
212 " disables this message.\n");
213 sched_show_task(t);
214 __debug_show_held_locks(t);
215
216 t->last_switch_timestamp = now;
217 touch_nmi_watchdog();
218
219 if (softlockup_panic)
220 panic("softlockup: blocked tasks");
221}
222
223/*
224 * Check whether a TASK_UNINTERRUPTIBLE does not get woken up for
225 * a really long time (120 seconds). If that happens, print out
226 * a warning.
227 */
228static void check_hung_uninterruptible_tasks(int this_cpu)
229{
230 int max_count = sysctl_hung_task_check_count;
231 unsigned long now = get_timestamp(this_cpu);
232 struct task_struct *g, *t;
233
234 /*
235 * If the system crashed already then all bets are off,
236 * do not report extra hung tasks:
237 */
238 if (test_taint(TAINT_DIE) || did_panic)
239 return;
240
241 read_lock(&tasklist_lock);
242 do_each_thread(g, t) {
243 if (!--max_count)
244 goto unlock;
245 /* use "==" to skip the TASK_KILLABLE tasks waiting on NFS */
246 if (t->state == TASK_UNINTERRUPTIBLE)
247 check_hung_task(t, now);
248 } while_each_thread(g, t);
249 unlock:
250 read_unlock(&tasklist_lock);
251}
252
253/*
254 * The watchdog thread - runs every second and touches the timestamp. 169 * The watchdog thread - runs every second and touches the timestamp.
255 */ 170 */
256static int watchdog(void *__bind_cpu) 171static int watchdog(void *__bind_cpu)
257{ 172{
258 struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 }; 173 struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 };
259 int this_cpu = (long)__bind_cpu;
260 174
261 sched_setscheduler(current, SCHED_FIFO, &param); 175 sched_setscheduler(current, SCHED_FIFO, &param);
262 176
@@ -276,11 +190,6 @@ static int watchdog(void *__bind_cpu)
276 if (kthread_should_stop()) 190 if (kthread_should_stop())
277 break; 191 break;
278 192
279 if (this_cpu == check_cpu) {
280 if (sysctl_hung_task_timeout_secs)
281 check_hung_uninterruptible_tasks(this_cpu);
282 }
283
284 set_current_state(TASK_INTERRUPTIBLE); 193 set_current_state(TASK_INTERRUPTIBLE);
285 } 194 }
286 __set_current_state(TASK_RUNNING); 195 __set_current_state(TASK_RUNNING);
@@ -312,18 +221,9 @@ cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu)
312 break; 221 break;
313 case CPU_ONLINE: 222 case CPU_ONLINE:
314 case CPU_ONLINE_FROZEN: 223 case CPU_ONLINE_FROZEN:
315 check_cpu = cpumask_any(cpu_online_mask);
316 wake_up_process(per_cpu(watchdog_task, hotcpu)); 224 wake_up_process(per_cpu(watchdog_task, hotcpu));
317 break; 225 break;
318#ifdef CONFIG_HOTPLUG_CPU 226#ifdef CONFIG_HOTPLUG_CPU
319 case CPU_DOWN_PREPARE:
320 case CPU_DOWN_PREPARE_FROZEN:
321 if (hotcpu == check_cpu) {
322 /* Pick any other online cpu. */
323 check_cpu = cpumask_any_but(cpu_online_mask, hotcpu);
324 }
325 break;
326
327 case CPU_UP_CANCELED: 227 case CPU_UP_CANCELED:
328 case CPU_UP_CANCELED_FROZEN: 228 case CPU_UP_CANCELED_FROZEN:
329 if (!per_cpu(watchdog_task, hotcpu)) 229 if (!per_cpu(watchdog_task, hotcpu))