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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v6 for Xen 4.7 1/4] xen: enable per-VCPU parameter settings for RTDS scheduler
Add XEN_DOMCTL_SCHEDOP_getvcpuinfo and _putvcpuinfo hypercalls
to independently get and set the scheduling parameters of each
vCPU of a domain
Signed-off-by: Chong Li <chong.li@xxxxxxxxx>
Signed-off-by: Meng Xu <mengxu@xxxxxxxxxxxxx>
Signed-off-by: Sisu Xi <xisisu@xxxxxxxxx>
---
Changes on PATCH v5:
1) When processing XEN_DOMCTL_SCHEDOP_get/putvcpuinfo, we do
preemption check in a similar way to XEN_SYSCTL_pcitopoinfo
Changes on PATCH v4:
1) Add uint32_t vcpu_index to struct xen_domctl_scheduler_op.
When processing XEN_DOMCTL_SCHEDOP_get/putvcpuinfo, we call
hypercall_preemption_check in case the current hypercall lasts
too long. If we decide to preempt the current hypercall, we record
the index of the most-recent finished vcpu into the vcpu_index of
struct xen_domctl_scheduler_op. So when we resume the hypercall after
preemption, we start processing from the posion specified by vcpu_index,
and don't need to repeat the work that has already been done in the
hypercall before the preemption.
(This design is based on the do_grant_table_op() in grant_table.c)
2) Coding style changes
Changes on PATCH v3:
1) Remove struct xen_domctl_schedparam_t.
2) Change struct xen_domctl_scheduler_op.
3) Check if period/budget is within a validated range
Changes on PATCH v2:
1) Change struct xen_domctl_scheduler_op, for transferring per-vcpu parameters
between libxc and hypervisor.
2) Handler of XEN_DOMCTL_SCHEDOP_getinfo now just returns the default budget and
period values of RTDS scheduler.
3) Handler of XEN_DOMCTL_SCHEDOP_getvcpuinfo now can return a random subset of
the parameters of the VCPUs of a specific domain
CC: <dario.faggioli@xxxxxxxxxx>
CC: <george.dunlap@xxxxxxxxxxxxx>
CC: <dgolomb@xxxxxxxxxxxxxx>
CC: <mengxu@xxxxxxxxxxxxx>
CC: <jbeulich@xxxxxxxx>
CC: <lichong659@xxxxxxxxx>
---
xen/common/sched_credit.c | 4 ++
xen/common/sched_credit2.c | 4 ++
xen/common/sched_rt.c | 130 +++++++++++++++++++++++++++++++++++++++-----
xen/common/schedule.c | 15 ++++-
xen/include/public/domctl.h | 59 ++++++++++++++++----
5 files changed, 182 insertions(+), 30 deletions(-)
diff --git a/xen/common/sched_credit.c b/xen/common/sched_credit.c
index 0dce790..455c684 100644
--- a/xen/common/sched_credit.c
+++ b/xen/common/sched_credit.c
@@ -1054,6 +1054,10 @@ csched_dom_cntl(
* lock. Runq lock not needed anywhere in here. */
spin_lock_irqsave(&prv->lock, flags);
+ if ( op->cmd == XEN_DOMCTL_SCHEDOP_putvcpuinfo ||
+ op->cmd == XEN_DOMCTL_SCHEDOP_getvcpuinfo )
+ return -EINVAL;
+
if ( op->cmd == XEN_DOMCTL_SCHEDOP_getinfo )
{
op->u.credit.weight = sdom->weight;
diff --git a/xen/common/sched_credit2.c b/xen/common/sched_credit2.c
index 3c49ffa..c3049a0 100644
--- a/xen/common/sched_credit2.c
+++ b/xen/common/sched_credit2.c
@@ -1421,6 +1421,10 @@ csched2_dom_cntl(
* runq lock to update csvcs. */
spin_lock_irqsave(&prv->lock, flags);
+ if ( op->cmd == XEN_DOMCTL_SCHEDOP_putvcpuinfo ||
+ op->cmd == XEN_DOMCTL_SCHEDOP_getvcpuinfo )
+ return -EINVAL;
+
if ( op->cmd == XEN_DOMCTL_SCHEDOP_getinfo )
{
op->u.credit2.weight = sdom->weight;
diff --git a/xen/common/sched_rt.c b/xen/common/sched_rt.c
index 3f1d047..4fcbf40 100644
--- a/xen/common/sched_rt.c
+++ b/xen/common/sched_rt.c
@@ -86,6 +86,22 @@
#define RTDS_DEFAULT_PERIOD (MICROSECS(10000))
#define RTDS_DEFAULT_BUDGET (MICROSECS(4000))
+/*
+ * Max period: max delta of time type, because period is added to the time
+ * a vcpu activates, so this must not overflow.
+ * Min period: 10 us, considering the scheduling overhead (when period is
+ * too low, scheduling is invoked too frequently, causing high overhead).
+ */
+#define RTDS_MAX_PERIOD (STIME_DELTA_MAX)
+#define RTDS_MIN_PERIOD (MICROSECS(10))
+
+/*
+ * Min budget: 10 us, considering the scheduling overhead (when budget is
+ * consumed too fast, scheduling is invoked too frequently, causing
+ * high overhead).
+ */
+#define RTDS_MIN_BUDGET (MICROSECS(10))
+
#define UPDATE_LIMIT_SHIFT 10
#define MAX_SCHEDULE (MILLISECS(1))
/*
@@ -1130,23 +1146,17 @@ rt_dom_cntl(
unsigned long flags;
int rc = 0;
+ xen_domctl_schedparam_vcpu_t local_sched;
+ s_time_t period, budget;
+ uint32_t index = 0;
+
switch ( op->cmd )
{
- case XEN_DOMCTL_SCHEDOP_getinfo:
- if ( d->max_vcpus > 0 )
- {
- spin_lock_irqsave(&prv->lock, flags);
- svc = rt_vcpu(d->vcpu[0]);
- op->u.rtds.period = svc->period / MICROSECS(1);
- op->u.rtds.budget = svc->budget / MICROSECS(1);
- spin_unlock_irqrestore(&prv->lock, flags);
- }
- else
- {
- /* If we don't have vcpus yet, let's just return the defaults. */
- op->u.rtds.period = RTDS_DEFAULT_PERIOD;
- op->u.rtds.budget = RTDS_DEFAULT_BUDGET;
- }
+ case XEN_DOMCTL_SCHEDOP_getinfo: /* return the default parameters */
+ spin_lock_irqsave(&prv->lock, flags);
+ op->u.rtds.period = RTDS_DEFAULT_PERIOD / MICROSECS(1);
+ op->u.rtds.budget = RTDS_DEFAULT_BUDGET / MICROSECS(1);
+ spin_unlock_irqrestore(&prv->lock, flags);
break;
case XEN_DOMCTL_SCHEDOP_putinfo:
if ( op->u.rtds.period == 0 || op->u.rtds.budget == 0 )
@@ -1163,6 +1173,96 @@ rt_dom_cntl(
}
spin_unlock_irqrestore(&prv->lock, flags);
break;
+ case XEN_DOMCTL_SCHEDOP_getvcpuinfo:
+ if ( guest_handle_is_null(op->u.v.vcpus) )
+ {
+ rc = -EINVAL;
+ break;
+ }
+ while ( index < op->u.v.nr_vcpus )
+ {
+ if ( copy_from_guest_offset(&local_sched,
+ op->u.v.vcpus, index, 1) )
+ {
+ rc = -EFAULT;
+ break;
+ }
+ if ( local_sched.vcpuid >= d->max_vcpus ||
+ d->vcpu[local_sched.vcpuid] == NULL )
+ {
+ rc = -EINVAL;
+ break;
+ }
+
+ spin_lock_irqsave(&prv->lock, flags);
+ svc = rt_vcpu(d->vcpu[local_sched.vcpuid]);
+ local_sched.s.rtds.budget = svc->budget / MICROSECS(1);
+ local_sched.s.rtds.period = svc->period / MICROSECS(1);
+ spin_unlock_irqrestore(&prv->lock, flags);
+
+ if ( __copy_to_guest_offset(op->u.v.vcpus, index,
+ &local_sched, 1) )
+ {
+ rc = -EFAULT;
+ break;
+ }
+ if ( (++index > 0x3f) && hypercall_preempt_check() )
+ break;
+ }
+
+ if ( !rc && (op->u.v.nr_vcpus != index) )
+ op->u.v.nr_vcpus = index;
+ break;
+ case XEN_DOMCTL_SCHEDOP_putvcpuinfo:
+ if ( guest_handle_is_null(op->u.v.vcpus) )
+ {
+ rc = -EINVAL;
+ break;
+ }
+ while ( index < op->u.v.nr_vcpus )
+ {
+ if ( copy_from_guest_offset(&local_sched,
+ op->u.v.vcpus, index, 1) )
+ {
+ rc = -EFAULT;
+ break;
+ }
+ if ( local_sched.vcpuid >= d->max_vcpus ||
+ d->vcpu[local_sched.vcpuid] == NULL )
+ {
+ rc = -EINVAL;
+ break;
+ }
+
+ period = MICROSECS(local_sched.s.rtds.period);
+ budget = MICROSECS(local_sched.s.rtds.budget);
+ if ( period > RTDS_MAX_PERIOD || budget < RTDS_MIN_BUDGET ||
+ budget > period || period < RTDS_MIN_PERIOD )
+ {
+ rc = -EINVAL;
+ break;
+ }
+
+ /*
+ * We accept period/budget less than 100 us, but will warn users
about
+ * the large scheduling overhead due to it
+ */
+ if ( period < MICROSECS(100) || budget < MICROSECS(100) )
+ printk("Warning: period or budget set to less than 100us.\n"
+ "This may result in high scheduling overhead.\n");
+
+ spin_lock_irqsave(&prv->lock, flags);
+ svc = rt_vcpu(d->vcpu[local_sched.vcpuid]);
+ svc->period = period;
+ svc->budget = budget;
+ spin_unlock_irqrestore(&prv->lock, flags);
+
+ if ( (++index > 0x3f) && hypercall_preempt_check() )
+ break;
+ }
+ if ( !rc && (op->u.v.nr_vcpus != index) )
+ op->u.v.nr_vcpus = index;
+ break;
}
return rc;
diff --git a/xen/common/schedule.c b/xen/common/schedule.c
index c195129..f4a4032 100644
--- a/xen/common/schedule.c
+++ b/xen/common/schedule.c
@@ -1148,10 +1148,19 @@ long sched_adjust(struct domain *d, struct
xen_domctl_scheduler_op *op)
if ( ret )
return ret;
- if ( (op->sched_id != DOM2OP(d)->sched_id) ||
- ((op->cmd != XEN_DOMCTL_SCHEDOP_putinfo) &&
- (op->cmd != XEN_DOMCTL_SCHEDOP_getinfo)) )
+ if ( op->sched_id != DOM2OP(d)->sched_id )
return -EINVAL;
+ else
+ switch ( op->cmd )
+ {
+ case XEN_DOMCTL_SCHEDOP_putinfo:
+ case XEN_DOMCTL_SCHEDOP_getinfo:
+ case XEN_DOMCTL_SCHEDOP_putvcpuinfo:
+ case XEN_DOMCTL_SCHEDOP_getvcpuinfo:
+ break;
+ default:
+ return -EINVAL;
+ }
/* NB: the pluggable scheduler code needs to take care
* of locking by itself. */
diff --git a/xen/include/public/domctl.h b/xen/include/public/domctl.h
index 7a56b3f..b9975f6 100644
--- a/xen/include/public/domctl.h
+++ b/xen/include/public/domctl.h
@@ -338,24 +338,59 @@ DEFINE_XEN_GUEST_HANDLE(xen_domctl_max_vcpus_t);
#define XEN_SCHEDULER_ARINC653 7
#define XEN_SCHEDULER_RTDS 8
-/* Set or get info? */
+typedef struct xen_domctl_sched_credit {
+ uint16_t weight;
+ uint16_t cap;
+} xen_domctl_sched_credit_t;
+
+typedef struct xen_domctl_sched_credit2 {
+ uint16_t weight;
+} xen_domctl_sched_credit2_t;
+
+typedef struct xen_domctl_sched_rtds {
+ uint32_t period;
+ uint32_t budget;
+} xen_domctl_sched_rtds_t;
+
+typedef struct xen_domctl_schedparam_vcpu {
+ union {
+ xen_domctl_sched_credit_t credit;
+ xen_domctl_sched_credit2_t credit2;
+ xen_domctl_sched_rtds_t rtds;
+ } s;
+ uint16_t vcpuid;
+ uint16_t padding[3];
+} xen_domctl_schedparam_vcpu_t;
+DEFINE_XEN_GUEST_HANDLE(xen_domctl_schedparam_vcpu_t);
+
+/*
+ * Set or get info?
+ * For schedulers supporting per-vcpu settings (e.g., RTDS):
+ * XEN_DOMCTL_SCHEDOP_putinfo sets params for all vcpus;
+ * XEN_DOMCTL_SCHEDOP_getinfo gets default params;
+ * XEN_DOMCTL_SCHEDOP_put(get)vcpuinfo sets (gets) params of vcpus;
+ *
+ * For schedulers not supporting per-vcpu settings:
+ * XEN_DOMCTL_SCHEDOP_putinfo sets params for all vcpus;
+ * XEN_DOMCTL_SCHEDOP_getinfo gets domain-wise params;
+ * XEN_DOMCTL_SCHEDOP_put(get)vcpuinfo returns error;
+ */
#define XEN_DOMCTL_SCHEDOP_putinfo 0
#define XEN_DOMCTL_SCHEDOP_getinfo 1
+#define XEN_DOMCTL_SCHEDOP_putvcpuinfo 2
+#define XEN_DOMCTL_SCHEDOP_getvcpuinfo 3
struct xen_domctl_scheduler_op {
uint32_t sched_id; /* XEN_SCHEDULER_* */
uint32_t cmd; /* XEN_DOMCTL_SCHEDOP_* */
union {
- struct xen_domctl_sched_credit {
- uint16_t weight;
- uint16_t cap;
- } credit;
- struct xen_domctl_sched_credit2 {
- uint16_t weight;
- } credit2;
- struct xen_domctl_sched_rtds {
- uint32_t period;
- uint32_t budget;
- } rtds;
+ xen_domctl_sched_credit_t credit;
+ xen_domctl_sched_credit2_t credit2;
+ xen_domctl_sched_rtds_t rtds;
+ struct {
+ XEN_GUEST_HANDLE_64(xen_domctl_schedparam_vcpu_t) vcpus;
+ uint32_t nr_vcpus;
+ uint32_t padding;
+ } v;
} u;
};
typedef struct xen_domctl_scheduler_op xen_domctl_scheduler_op_t;
--
1.9.1
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