This patch is from Nathan Lynch <[EMAIL PROTECTED]>.
The rtasd thread should not hold the cpucontrol semaphore while
sleeping between event scans in its first pass; it needlessly delays
boot by one second per cpu when CONFIG_HOTPLUG_CPU=y.
Signed-off-by: Nathan Lynch <[EMAIL PROTECTED]>
Signed-off-by: Paul Mackerras <[EMAIL PROTECTED]>
--- linux-2.6.11.orig/arch/ppc64/kernel/rtasd.c 2005-02-20 02:08:49.000000000
+0000
+++ linux-2.6.11/arch/ppc64/kernel/rtasd.c 2005-02-20 18:13:54.000000000
+0000
@@ -400,10 +400,33 @@
} while(error == 0);
}
+static void do_event_scan_all_cpus(long delay)
+{
+ int cpu;
+
+ lock_cpu_hotplug();
+ cpu = first_cpu(cpu_online_map);
+ for (;;) {
+ set_cpus_allowed(current, cpumask_of_cpu(cpu));
+ do_event_scan(rtas_token("event-scan"));
+ set_cpus_allowed(current, CPU_MASK_ALL);
+
+ /* Drop hotplug lock, and sleep for the specified delay */
+ unlock_cpu_hotplug();
+ set_current_state(TASK_INTERRUPTIBLE);
+ schedule_timeout(delay);
+ lock_cpu_hotplug();
+
+ cpu = next_cpu(cpu, cpu_online_map);
+ if (cpu == NR_CPUS)
+ break;
+ }
+ unlock_cpu_hotplug();
+}
+
static int rtasd(void *unused)
{
unsigned int err_type;
- int cpu = 0;
int event_scan = rtas_token("event-scan");
int rc;
@@ -437,17 +460,7 @@
}
/* First pass. */
- lock_cpu_hotplug();
- for_each_online_cpu(cpu) {
- DEBUG("scheduling on %d\n", cpu);
- set_cpus_allowed(current, cpumask_of_cpu(cpu));
- DEBUG("watchdog scheduled on cpu %d\n", smp_processor_id());
-
- do_event_scan(event_scan);
- set_current_state(TASK_INTERRUPTIBLE);
- schedule_timeout(HZ);
- }
- unlock_cpu_hotplug();
+ do_event_scan_all_cpus(HZ);
if (surveillance_timeout != -1) {
DEBUG("enabling surveillance\n");
@@ -455,25 +468,11 @@
DEBUG("surveillance enabled\n");
}
- lock_cpu_hotplug();
- cpu = first_cpu(cpu_online_map);
- for (;;) {
- set_cpus_allowed(current, cpumask_of_cpu(cpu));
- do_event_scan(event_scan);
- set_cpus_allowed(current, CPU_MASK_ALL);
-
- /* Drop hotplug lock, and sleep for a bit (at least
- * one second since some machines have problems if we
- * call event-scan too quickly). */
- unlock_cpu_hotplug();
- set_current_state(TASK_INTERRUPTIBLE);
- schedule_timeout((HZ*60/rtas_event_scan_rate) / 2);
- lock_cpu_hotplug();
-
- cpu = next_cpu(cpu, cpu_online_map);
- if (cpu == NR_CPUS)
- cpu = first_cpu(cpu_online_map);
- }
+ /* Delay should be at least one second since some
+ * machines have problems if we call event-scan too
+ * quickly. */
+ for (;;)
+ do_event_scan_all_cpus((HZ*60/rtas_event_scan_rate) / 2);
error:
/* Should delete proc entries */
-
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