[Xen-devel] [PATCH v2] xen/sched: add some diagnostic info in the run queue keyhandler

[Juergen Gross <jgross@suse.com>]

When dumping the run queue information add some more data regarding
current and (if known) previous vcpu for each physical cpu.

With core scheduling activated the printed data will be e.g.:

(XEN) CPUs info:
(XEN) CPU[00] current=d[IDLE]v0, curr=d[IDLE]v0, prev=NULL
(XEN) CPU[01] current=d[IDLE]v1
(XEN) CPU[02] current=d[IDLE]v2, curr=d[IDLE]v2, prev=NULL
(XEN) CPU[03] current=d[IDLE]v3

Signed-off-by: Juergen Gross <jgross@suse.com>
---
V2: add proper locking
---
 xen/common/sched/core.c | 26 ++++++++++++++++++++------
 1 file changed, 20 insertions(+), 6 deletions(-)

diff --git a/xen/common/sched/core.c b/xen/common/sched/core.c
index 2e43f8029f..6fbc30e678 100644
--- a/xen/common/sched/core.c
+++ b/xen/common/sched/core.c
@@ -3234,7 +3234,7 @@ void scheduler_free(struct scheduler *sched)
 
 void schedule_dump(struct cpupool *c)
 {
-    unsigned int      i;
+    unsigned int      i, j;
     struct scheduler *sched;
     cpumask_t        *cpus;
 
@@ -3245,7 +3245,7 @@ void schedule_dump(struct cpupool *c)
     if ( c != NULL )
     {
         sched = c->sched;
-        cpus = c->cpu_valid;
+        cpus = c->res_valid;
         printk("Scheduler: %s (%s)\n", sched->name, sched->opt_name);
         sched_dump_settings(sched);
     }
@@ -3255,11 +3255,25 @@ void schedule_dump(struct cpupool *c)
         cpus = &cpupool_free_cpus;
     }
 
-    if ( sched->dump_cpu_state != NULL )
+    printk("CPUs info:\n");
+    for_each_cpu (i, cpus)
     {
-        printk("CPUs info:\n");
-        for_each_cpu (i, cpus)
-            sched_dump_cpu_state(sched, i);
+        struct sched_resource *sr = get_sched_res(i);
+        unsigned long flags;
+        spinlock_t *lock;
+
+        lock = pcpu_schedule_lock_irqsave(i, &flags);
+
+        printk("CPU[%02d] current=%pv, curr=%pv, prev=%pv\n", i,
+               get_cpu_current(i), sr->curr ? sr->curr->vcpu_list : NULL,
+               sr->prev ? sr->prev->vcpu_list : NULL);
+        for_each_cpu (j, sr->cpus)
+            if ( i != j )
+                printk("CPU[%02d] current=%pv\n", j, get_cpu_current(j));
+
+        pcpu_schedule_unlock_irqrestore(lock, flags, i);
+
+        sched_dump_cpu_state(sched, i);
     }
 
     rcu_read_unlock(&sched_res_rculock);
-- 
2.16.4


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