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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH 1 of 1] sched: rework locking for dump debugkey.
As in all other paths, locking should be dealt with in the
specific schedulers, not in schedule.c.
Signed-off-by: Dario Faggioli <dario.faggioli@xxxxxxxxxx>
diff -r 15ab61865ecb xen/common/sched_credit.c
--- a/xen/common/sched_credit.c Tue Jan 17 12:40:52 2012 +0000
+++ b/xen/common/sched_credit.c Wed Jan 18 15:02:30 2012 +0000
@@ -1451,11 +1451,16 @@ static void
csched_dump_pcpu(const struct scheduler *ops, int cpu)
{
struct list_head *runq, *iter;
+ struct csched_private *prv = CSCHED_PRIV(ops);
struct csched_pcpu *spc;
struct csched_vcpu *svc;
+ unsigned long flags;
int loop;
#define cpustr keyhandler_scratch
+ /* Domains' parameters are changed under csched_priv lock */
+ spin_lock_irqsave(&prv->lock, flags);
+
spc = CSCHED_PCPU(cpu);
runq = &spc->runq;
@@ -1464,6 +1469,12 @@ csched_dump_pcpu(const struct scheduler
cpumask_scnprintf(cpustr, sizeof(cpustr), per_cpu(cpu_core_mask, cpu));
printk("core=%s\n", cpustr);
+ /*
+ * We need runq lock as well, and as there's one runq per CPU,
+ * this is the correct one to take for this CPU/runq.
+ */
+ pcpu_schedule_lock(cpu);
+
/* current VCPU */
svc = CSCHED_VCPU(per_cpu(schedule_data, cpu).curr);
if ( svc )
@@ -1482,6 +1493,9 @@ csched_dump_pcpu(const struct scheduler
csched_dump_vcpu(svc);
}
}
+
+ pcpu_schedule_unlock(cpu);
+ spin_unlock_irqrestore(&prv->lock, flags);
#undef cpustr
}
@@ -1493,7 +1507,7 @@ csched_dump(const struct scheduler *ops)
int loop;
unsigned long flags;
- spin_lock_irqsave(&(prv->lock), flags);
+ spin_lock_irqsave(&prv->lock, flags);
#define idlers_buf keyhandler_scratch
@@ -1537,12 +1551,14 @@ csched_dump(const struct scheduler *ops)
svc = list_entry(iter_svc, struct csched_vcpu, active_vcpu_elem);
printk("\t%3d: ", ++loop);
+ vcpu_schedule_lock(svc->vcpu);
csched_dump_vcpu(svc);
+ vcpu_schedule_unlock(svc->vcpu);
}
}
#undef idlers_buf
- spin_unlock_irqrestore(&(prv->lock), flags);
+ spin_unlock_irqrestore(&prv->lock, flags);
}
static int
diff -r 15ab61865ecb xen/common/sched_credit2.c
--- a/xen/common/sched_credit2.c Tue Jan 17 12:40:52 2012 +0000
+++ b/xen/common/sched_credit2.c Wed Jan 18 15:02:30 2012 +0000
@@ -53,8 +53,6 @@
* credit2 wiki page:
* http://wiki.xen.org/wiki/Credit2_Scheduler_Development
* TODO:
- * + Immediate bug-fixes
- * - Do per-runqueue, grab proper lock for dump debugkey
* + Multiple sockets
* - Detect cpu layout and make runqueue map, one per L2 (make_runq_map())
* - Simple load balancer / runqueue assignment
@@ -1759,12 +1757,16 @@ csched_dump_vcpu(struct csched_vcpu *svc
static void
csched_dump_pcpu(const struct scheduler *ops, int cpu)
{
+ struct csched_private *prv = CSCHED_PRIV(ops);
struct list_head *runq, *iter;
struct csched_vcpu *svc;
+ unsigned long flags;
+ spinlock_t *lock;
int loop;
char cpustr[100];
- /* FIXME: Do locking properly for access to runqueue structures */
+ /* Domains' parameters are changed under csched_priv lock */
+ spin_lock_irqsave(&prv->lock, flags);
runq = &RQD(ops, cpu)->runq;
@@ -1773,6 +1775,13 @@ csched_dump_pcpu(const struct scheduler
cpumask_scnprintf(cpustr, sizeof(cpustr), per_cpu(cpu_core_mask, cpu));
printk("core=%s\n", cpustr);
+ /*
+ * We need runq lock as well, and here's how we get to it
+ * for the requested cpu.
+ */
+ lock = per_cpu(schedule_data, cpu).schedule_lock;
+ spin_lock(lock);
+
/* current VCPU */
svc = CSCHED_VCPU(per_cpu(schedule_data, cpu).curr);
if ( svc )
@@ -1791,6 +1800,9 @@ csched_dump_pcpu(const struct scheduler
csched_dump_vcpu(svc);
}
}
+
+ spin_unlock(lock);
+ spin_unlock_irqrestore(&prv->lock, flags);
}
static void
@@ -1798,8 +1810,11 @@ csched_dump(const struct scheduler *ops)
{
struct list_head *iter_sdom, *iter_svc;
struct csched_private *prv = CSCHED_PRIV(ops);
+ unsigned long flags;
int i, loop;
+ spin_lock_irqsave(&prv->lock, flags);
+
printk("Active queues: %d\n"
"\tdefault-weight = %d\n",
cpumask_weight(&prv->active_queues),
@@ -1822,7 +1837,6 @@ csched_dump(const struct scheduler *ops)
fraction);
}
- /* FIXME: Locking! */
printk("Domain info:\n");
loop = 0;
@@ -1831,10 +1845,10 @@ csched_dump(const struct scheduler *ops)
struct csched_dom *sdom;
sdom = list_entry(iter_sdom, struct csched_dom, sdom_elem);
- printk("\tDomain: %d w %d v %d\n\t",
- sdom->dom->domain_id,
- sdom->weight,
- sdom->nr_vcpus);
+ printk("\tDomain: %d w %d v %d\n\t",
+ sdom->dom->domain_id,
+ sdom->weight,
+ sdom->nr_vcpus);
list_for_each( iter_svc, &sdom->vcpu )
{
@@ -1842,9 +1856,13 @@ csched_dump(const struct scheduler *ops)
svc = list_entry(iter_svc, struct csched_vcpu, sdom_elem);
printk("\t%3d: ", ++loop);
+ vcpu_schedule_lock(svc->vcpu);
csched_dump_vcpu(svc);
+ vcpu_schedule_unlock(svc->vcpu);
}
}
+
+ spin_unlock_irqrestore(&prv->lock, flags);
}
static void activate_runqueue(struct csched_private *prv, int rqi)
diff -r 15ab61865ecb xen/common/sched_sedf.c
--- a/xen/common/sched_sedf.c Tue Jan 17 12:40:52 2012 +0000
+++ b/xen/common/sched_sedf.c Wed Jan 18 15:02:30 2012 +0000
@@ -1219,13 +1219,25 @@ static void sedf_dump_domain(struct vcpu
/* Dumps all domains on the specified cpu */
static void sedf_dump_cpu_state(const struct scheduler *ops, int i)
{
+ struct sedf_priv_info *prv = SEDF_PRIV(ops);
struct list_head *list, *queue, *tmp;
struct sedf_vcpu_info *d_inf;
struct domain *d;
struct vcpu *ed;
+ unsigned long flags;
int loop = 0;
+
+ /* Domains' parameters are changed under scheduler lock */
+ spin_lock_irqsave(&prv->lock, flags);
printk("now=%"PRIu64"\n",NOW());
+
+ /*
+ * We need runq lock as well, and as there's one runq per CPU,
+ * this is the correct one to take for this CPU/runq.
+ */
+ pcpu_schedule_lock(i);
+
queue = RUNQ(i);
printk("RUNQ rq %lx n: %lx, p: %lx\n", (unsigned long)queue,
(unsigned long) queue->next, (unsigned long) queue->prev);
@@ -1288,6 +1300,9 @@ static void sedf_dump_cpu_state(const st
}
}
rcu_read_unlock(&domlist_read_lock);
+
+ pcpu_schedule_unlock(i);
+ spin_unlock_irqrestore(&prv->lock, flags);
}
diff -r 15ab61865ecb xen/common/schedule.c
--- a/xen/common/schedule.c Tue Jan 17 12:40:52 2012 +0000
+++ b/xen/common/schedule.c Wed Jan 18 15:02:30 2012 +0000
@@ -1417,6 +1417,7 @@ void schedule_dump(struct cpupool *c)
struct scheduler *sched;
cpumask_t *cpus;
+ /* Proper locking is provided by each scheduler */
sched = (c == NULL) ? &ops : c->sched;
cpus = (c == NULL) ? &cpupool_free_cpus : c->cpu_valid;
printk("Scheduler: %s (%s)\n", sched->name, sched->opt_name);
@@ -1424,10 +1425,8 @@ void schedule_dump(struct cpupool *c)
for_each_cpu (i, cpus)
{
- pcpu_schedule_lock(i);
printk("CPU[%02d] ", i);
SCHED_OP(sched, dump_cpu_state, i);
- pcpu_schedule_unlock(i);
}
}
--
<<This happens because I choose it to happen!>> (Raistlin Majere)
-------------------------------------------------------------------
Dario Faggioli, http://retis.sssup.it/people/faggioli
Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK)
PhD Candidate, ReTiS Lab, Scuola Superiore Sant'Anna, Pisa (Italy)
Attachment:
rework-locking-for-dump-status.patch Attachment:
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