Several refactorizations:
* Add prv->initialized cpu mask
* Replace prv->runq_count with active_queue mask
* Replace rqd->cpu_min,cpu_mask with active cpu mask
* Put locks in the runqueue structure, rather than borrowing the existing
cpu locks
* init() initializes all runqueues to NULL, inactive, and maps all pcpus to
runqueue -q
* alloc_pcpu() will add cpus to runqueues, "activating" the runqueue if
necessary. All cpus are currently assigned to runqueue 0.
End-to-end behavior of the system should remain largely the same.
Signed-off-by: George Dunlap <george.dunlap@xxxxxxxxxxxxx>
diff -r 666ca1dd3ca7 -r b4aeb2f27741 xen/common/sched_credit2.c
--- a/xen/common/sched_credit2.c Thu Dec 23 12:24:29 2010 +0000
+++ b/xen/common/sched_credit2.c Thu Dec 23 12:24:48 2010 +0000
@@ -176,10 +176,14 @@
*/
struct csched_runqueue_data {
int id;
+
+ spinlock_t lock; /* Lock for this runqueue. */
+ cpumask_t active; /* CPUs enabled for this runqueue */
+
struct list_head runq; /* Ordered list of runnable vms */
struct list_head svc; /* List of all vcpus assigned to this runqueue */
int max_weight;
- int cpu_min, cpu_max; /* Range of physical cpus this runqueue runs */
+
cpumask_t idle, /* Currently idle */
tickled; /* Another cpu in the queue is already targeted for
this one */
};
@@ -189,12 +193,12 @@
*/
struct csched_private {
spinlock_t lock;
- uint32_t ncpus;
-
+ cpumask_t initialized; /* CPU is initialized for this pool */
+
struct list_head sdom; /* Used mostly for dump keyhandler. */
int runq_map[NR_CPUS];
- uint32_t runq_count;
+ cpumask_t active_queues; /* Queues which may have active cpus */
struct csched_runqueue_data rqd[NR_CPUS];
};
@@ -341,7 +345,7 @@
int i, ipid=-1;
s_time_t lowest=(1<<30);
struct csched_runqueue_data *rqd = RQD(ops, cpu);
- cpumask_t *online, mask;
+ cpumask_t mask;
struct csched_vcpu * cur;
d2printk("rqt d%dv%d cd%dv%d\n",
@@ -374,9 +378,7 @@
/* Otherwise, look for the non-idle cpu with the lowest credit,
* skipping cpus which have been tickled but not scheduled yet */
- online = CSCHED_CPUONLINE(per_cpu(cpupool, cpu));
-
- cpus_andnot(mask, *online, rqd->idle);
+ cpus_andnot(mask, rqd->active, rqd->idle);
cpus_andnot(mask, mask, rqd->tickled);
for_each_cpu_mask(i, mask)
@@ -997,7 +999,7 @@
const struct scheduler *ops, s_time_t now, bool_t tasklet_work_scheduled)
{
const int cpu = smp_processor_id();
- struct csched_runqueue_data *rqd = RQD(ops, cpu);
+ struct csched_runqueue_data *rqd;
struct csched_vcpu * const scurr = CSCHED_VCPU(current);
struct csched_vcpu *snext = NULL;
struct task_slice ret;
@@ -1010,6 +1012,10 @@
scurr->vcpu->vcpu_id,
now);
+ BUG_ON(!cpu_isset(cpu, CSCHED_PRIV(ops)->initialized));
+
+ rqd = RQD(ops, cpu);
+ BUG_ON(!cpu_isset(cpu, rqd->active));
/* Protected by runqueue lock */
@@ -1166,14 +1172,22 @@
{
struct list_head *iter_sdom, *iter_svc;
struct csched_private *prv = CSCHED_PRIV(ops);
- int loop;
+ int i, loop;
- printk("info:\n"
- "\tncpus = %u\n"
+ printk("Active queues: %d\n"
"\tdefault-weight = %d\n",
- prv->ncpus,
+ cpus_weight(prv->active_queues),
CSCHED_DEFAULT_WEIGHT);
+ for_each_cpu_mask(i, prv->active_queues)
+ {
+ printk("Runqueue %d:\n"
+ "\tncpus = %u\n"
+ "\tmax_weight = %d\n",
+ i,
+ cpus_weight(prv->rqd[i].active),
+ prv->rqd[i].max_weight);
+ }
/* FIXME: Locking! */
printk("Domain info:\n");
@@ -1199,16 +1213,82 @@
}
}
-static void
-csched_free_pdata(const struct scheduler *ops, void *pcpu, int cpu)
+static void activate_runqueue(struct csched_private *prv, int rqi)
{
- unsigned long flags;
+ struct csched_runqueue_data *rqd;
+
+ rqd = prv->rqd + rqi;
+
+ BUG_ON(!cpus_empty(rqd->active));
+
+ rqd->max_weight = 1;
+ rqd->id = rqi;
+ INIT_LIST_HEAD(&rqd->svc);
+ INIT_LIST_HEAD(&rqd->runq);
+ spin_lock_init(&rqd->lock);
+
+ cpu_set(rqi, prv->active_queues);
+}
+
+static void deactivate_runqueue(struct csched_private *prv, int rqi)
+{
+ struct csched_runqueue_data *rqd;
+
+ rqd = prv->rqd + rqi;
+
+ BUG_ON(!cpus_empty(rqd->active));
+
+ rqd->id = -1;
+
+ cpu_clear(rqi, prv->active_queues);
+}
+
+static void init_pcpu(const struct scheduler *ops, int cpu)
+{
+ int rqi, old_rqi, flags;
struct csched_private *prv = CSCHED_PRIV(ops);
+ struct csched_runqueue_data *rqd;
+ spinlock_t *old_lock;
spin_lock_irqsave(&prv->lock, flags);
- prv->ncpus--;
- cpu_clear(cpu, RQD(ops, cpu)->idle);
- printk("Removing cpu %d to pool (%d total)\n", cpu, prv->ncpus);
+
+ if ( cpu_isset(cpu, prv->initialized) )
+ {
+ printk("%s: Strange, cpu %d already initialized!\n", __func__, cpu);
+ spin_unlock_irqrestore(&prv->lock, flags);
+ return;
+ }
+
+ old_rqi = prv->runq_map[cpu];
+
+ /* Figure out which runqueue to put it in */
+ rqi = 0;
+
+ rqd=prv->rqd + rqi;
+
+ printk("Adding cpu %d to runqueue %d\n", cpu, rqi);
+ if ( ! cpu_isset(rqi, prv->active_queues) )
+ {
+ printk(" First cpu on runqueue, activating\n");
+ activate_runqueue(prv, rqi);
+ }
+
+ /* IRQs already disabled */
+ old_lock=pcpu_schedule_lock(cpu);
+
+ /* Move spinlock to new runq lock. */
+ per_cpu(schedule_data, cpu).schedule_lock = &rqd->lock;
+
+ /* Set the runqueue map */
+ prv->runq_map[cpu]=rqi;
+
+ cpu_set(cpu, rqd->idle);
+ cpu_set(cpu, rqd->active);
+
+ spin_unlock(old_lock);
+
+ cpu_set(cpu, prv->initialized);
+
spin_unlock_irqrestore(&prv->lock, flags);
return;
@@ -1217,33 +1297,51 @@
static void *
csched_alloc_pdata(const struct scheduler *ops, int cpu)
{
- spinlock_t *new_lock;
- spinlock_t *old_lock = per_cpu(schedule_data, cpu).schedule_lock;
- unsigned long flags;
- struct csched_private *prv = CSCHED_PRIV(ops);
-
- spin_lock_irqsave(old_lock, flags);
- new_lock = &per_cpu(schedule_data, prv->runq_map[cpu])._lock;
- per_cpu(schedule_data, cpu).schedule_lock = new_lock;
- spin_unlock_irqrestore(old_lock, flags);
-
- spin_lock_irqsave(&prv->lock, flags);
- prv->ncpus++;
- cpu_set(cpu, RQD(ops, cpu)->idle);
- printk("Adding cpu %d to pool (%d total)\n", cpu, prv->ncpus);
- spin_unlock_irqrestore(&prv->lock, flags);
+ init_pcpu(ops, cpu);
return (void *)1;
}
static void
-make_runq_map(struct csched_private *prv)
+csched_free_pdata(const struct scheduler *ops, void *pcpu, int cpu)
{
- /* FIXME: Read pcpu layout and do this properly */
- prv->runq_count = 1;
- prv->rqd[0].cpu_min = 0;
- prv->rqd[0].cpu_max = NR_CPUS;
- memset(prv->runq_map, 0, sizeof(prv->runq_map));
+ unsigned long flags;
+ struct csched_private *prv = CSCHED_PRIV(ops);
+ struct csched_runqueue_data *rqd;
+ int rqi;
+
+ spin_lock_irqsave(&prv->lock, flags);
+
+ BUG_ON( !cpu_isset(cpu, prv->initialized));
+
+ /* Find the old runqueue and remove this cpu from it */
+ rqi = prv->runq_map[cpu];
+
+ rqd = prv->rqd + rqi;
+
+ /* No need to save IRQs here, they're already disabled */
+ spin_lock(&rqd->lock);
+
+ BUG_ON(!cpu_isset(cpu, rqd->idle));
+
+ printk("Removing cpu %d from runqueue %d\n", cpu, rqi);
+
+ cpu_clear(cpu, rqd->idle);
+ cpu_clear(cpu, rqd->active);
+
+ if ( cpus_empty(rqd->active) )
+ {
+ printk(" No cpus left on runqueue, disabling\n");
+ deactivate_runqueue(prv, rqi);
+ }
+
+ spin_unlock(&rqd->lock);
+
+ cpu_clear(cpu, prv->initialized);
+
+ spin_unlock_irqrestore(&prv->lock, flags);
+
+ return;
}
static int
@@ -1265,18 +1363,11 @@
spin_lock_init(&prv->lock);
INIT_LIST_HEAD(&prv->sdom);
- prv->ncpus = 0;
-
- make_runq_map(prv);
-
- for ( i=0; i<prv->runq_count ; i++ )
+ /* But un-initialize all runqueues */
+ for ( i=0; i<NR_CPUS; i++)
{
- struct csched_runqueue_data *rqd = prv->rqd + i;
-
- rqd->max_weight = 1;
- rqd->id = i;
- INIT_LIST_HEAD(&rqd->svc);
- INIT_LIST_HEAD(&rqd->runq);
+ prv->runq_map[i] = -1;
+ prv->rqd[i].id = -1;
}
return 0;
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