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Merge "sched: Fix deadlock between cpu hotplug and upmigrate change"

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Linux Build Service Account 2017-01-04 03:25:34 -08:00 • committed by Gerrit - the friendly Code Review server
commit 9a18201fc8
1 changed files with 19 additions and 8 deletions
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27
kernel/sched/hmp.c
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@ -1470,7 +1470,20 @@ int sched_hmp_proc_update_handler(struct ctl_table *table, int write,
int ret; int ret;
unsigned int old_val; unsigned int old_val;
unsigned int *data = (unsigned int *)table->data; unsigned int *data = (unsigned int *)table->data;
int update_min_nice = 0; int update_task_count = 0;
if (!sched_enable_hmp)
return 0;
/*
* The policy mutex is acquired with cpu_hotplug.lock
* held from cpu_up()->cpufreq_governor_interactive()->
* sched_set_window(). So enforce the same order here.
*/
if (write && (data == &sysctl_sched_upmigrate_pct)) {
update_task_count = 1;
get_online_cpus();
}
mutex_lock(&policy_mutex); mutex_lock(&policy_mutex);
@ -1478,7 +1491,7 @@ int sched_hmp_proc_update_handler(struct ctl_table *table, int write,
ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
if (ret || !write || !sched_enable_hmp) if (ret || !write)
goto done; goto done;
if (write && (old_val == *data)) if (write && (old_val == *data))
@ -1500,20 +1513,18 @@ int sched_hmp_proc_update_handler(struct ctl_table *table, int write,
* includes taking runqueue lock of all online cpus and re-initiatizing * includes taking runqueue lock of all online cpus and re-initiatizing
* their big counter values based on changed criteria. * their big counter values based on changed criteria.
*/ */
if ((data == &sysctl_sched_upmigrate_pct || update_min_nice)) { if (update_task_count)
get_online_cpus();
pre_big_task_count_change(cpu_online_mask); pre_big_task_count_change(cpu_online_mask);
}
set_hmp_defaults(); set_hmp_defaults();
if ((data == &sysctl_sched_upmigrate_pct || update_min_nice)) { if (update_task_count)
post_big_task_count_change(cpu_online_mask); post_big_task_count_change(cpu_online_mask);
put_online_cpus();
}
done: done:
mutex_unlock(&policy_mutex); mutex_unlock(&policy_mutex);
if (update_task_count)
put_online_cpus();
return ret; return ret;
} }