Re: [PATCH v2 for Xen 4.6 1/4] xen: enabling XL to set per-VCPU parameters of a domain for RTDS scheduler

[Dario Faggioli <dario.faggioli@citrix.com>]

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On Mon, 2015-05-25 at 19:05 -0500, Chong Li wrote:

> diff --git a/xen/common/domctl.c b/xen/common/domctl.c
> index 28aea55..8143c44 100644
> --- a/xen/common/domctl.c
> +++ b/xen/common/domctl.c
> @@ -841,6 +841,11 @@ long do_domctl(XEN_GUEST_HANDLE_PARAM(xen_domctl_t) u_domctl)
>          copyback = 1;
>          break;
>  
> +    case XEN_DOMCTL_scheduler_vcpu_op:
> +        ret = sched_adjust_vcpu(d, &op->u.scheduler_vcpu_op);
> +        copyback = 1;
> +        break;
> +
>
So, thinking more about this, do we really want a full new DOMCTL, or do
we want to instrument XEN_DOMCTL_scheduler_op? That would mean adding
two operations there, and fiddling with struct xen_domctl_scheduler_op?

The problem I see is that, whatever I imagine putting this, there would
be some redundancy.

Quick-&-dirty, I put together the below... would it possibly make sense?

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 union xen_domctl_schedparam {                     
    xen_domctl_sched_credit_t credit;            
    xen_domctl_sched_credit2_t credit2;
    xen_domctl_sched_rtds_t rtds;
} xen_domctl_schedparam_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; 
} xen_domctl_schedparam_vcpu_t;
DEFINE_XEN_GUEST_HANDLE(xen_domctl_schedparam_vcpu_t);
        
/* Set or get info? */
#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 {
        xen_domctl_schedparam_t d;
        struct {
            XEN_GUEST_HANDLE_64(xen_domctl_schedparam_vcpu_t) vcpus;
            uint16_t nr_vcpus;
        } v;                         
    } u;    
}; 
typedef struct xen_domctl_scheduler_op xen_domctl_scheduler_op_t;
DEFINE_XEN_GUEST_HANDLE(xen_domctl_scheduler_op_t);

I'm also attaching a (build-tested only) patch to that effect (I'm
killing SEDF in there, so I don't have to care about it, as it's going
away anyway).

Thoughts?

>  /*
> - * set/get each vcpu info of each domain
> + * set/get per-domain params of a domain
>   */
>  static int
>  rt_dom_cntl(
> @@ -1115,6 +1115,74 @@ rt_dom_cntl(
>      return rc;
>  }
>  
> +/*
> + * set/get per-vcpu params of a domain
> + */
> +static int
> +rt_vcpu_cntl(
> +    const struct scheduler *ops,
> +    struct domain *d,
> +    struct xen_domctl_scheduler_vcpu_op *op)
> +{
>
I commented this function already, while replying to Jan.
 
> +/* Adjust scheduling parameter for the vcpus of a given domain. */
> +long sched_adjust_vcpu(
> +    struct domain *d,
> +    struct xen_domctl_scheduler_vcpu_op *op)
> +{
>
Actually, I don't think you even need this function.

Especially if we take the path of doing all this as subops of
DOMCTL_scheduler_op, you can just use sched_adjust, do some more
multiplexing in there, and the call the proper scheduler hook.

Thanks and Regards,
Dario

-- 
<<This happens because I choose it to happen!>> (Raistlin Majere)
-----------------------------------------------------------------
Dario Faggioli, Ph.D, http://about.me/dario.faggioli
Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK)


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diff --git a/xen/common/Makefile b/xen/common/Makefile
index 1cddebc..3fdf931 100644
--- a/xen/common/Makefile
+++ b/xen/common/Makefile
@@ -31,7 +31,6 @@ obj-y += rbtree.o
 obj-y += rcupdate.o
 obj-y += sched_credit.o
 obj-y += sched_credit2.o
-obj-y += sched_sedf.o
 obj-y += sched_arinc653.o
 obj-y += sched_rt.o
 obj-y += schedule.o
diff --git a/xen/common/sched_credit.c b/xen/common/sched_credit.c
index 953ecb0..43b086b 100644
--- a/xen/common/sched_credit.c
+++ b/xen/common/sched_credit.c
@@ -1039,25 +1039,25 @@ csched_dom_cntl(
 
     if ( op->cmd == XEN_DOMCTL_SCHEDOP_getinfo )
     {
-        op->u.credit.weight = sdom->weight;
-        op->u.credit.cap = sdom->cap;
+        op->u.d.credit.weight = sdom->weight;
+        op->u.d.credit.cap = sdom->cap;
     }
     else
     {
         ASSERT(op->cmd == XEN_DOMCTL_SCHEDOP_putinfo);
 
-        if ( op->u.credit.weight != 0 )
+        if ( op->u.d.credit.weight != 0 )
         {
             if ( !list_empty(&sdom->active_sdom_elem) )
             {
                 prv->weight -= sdom->weight * sdom->active_vcpu_count;
-                prv->weight += op->u.credit.weight * sdom->active_vcpu_count;
+                prv->weight += op->u.d.credit.weight * sdom->active_vcpu_count;
             }
-            sdom->weight = op->u.credit.weight;
+            sdom->weight = op->u.d.credit.weight;
         }
 
-        if ( op->u.credit.cap != (uint16_t)~0U )
-            sdom->cap = op->u.credit.cap;
+        if ( op->u.d.credit.cap != (uint16_t)~0U )
+            sdom->cap = op->u.d.credit.cap;
 
     }
 
diff --git a/xen/common/sched_credit2.c b/xen/common/sched_credit2.c
index 75e0321..8992423 100644
--- a/xen/common/sched_credit2.c
+++ b/xen/common/sched_credit2.c
@@ -1438,20 +1438,20 @@ csched2_dom_cntl(
 
     if ( op->cmd == XEN_DOMCTL_SCHEDOP_getinfo )
     {
-        op->u.credit2.weight = sdom->weight;
+        op->u.d.credit2.weight = sdom->weight;
     }
     else
     {
         ASSERT(op->cmd == XEN_DOMCTL_SCHEDOP_putinfo);
 
-        if ( op->u.credit2.weight != 0 )
+        if ( op->u.d.credit2.weight != 0 )
         {
             struct list_head *iter;
             int old_weight;
 
             old_weight = sdom->weight;
 
-            sdom->weight = op->u.credit2.weight;
+            sdom->weight = op->u.d.credit2.weight;
 
             /* Update weights for vcpus, and max_weight for runqueues on which they reside */
             list_for_each ( iter, &sdom->vcpu )
diff --git a/xen/common/sched_rt.c b/xen/common/sched_rt.c
index 7c39a9e..c7efda3 100644
--- a/xen/common/sched_rt.c
+++ b/xen/common/sched_rt.c
@@ -1091,12 +1091,12 @@ rt_dom_cntl(
     case XEN_DOMCTL_SCHEDOP_getinfo:
         spin_lock_irqsave(&prv->lock, flags);
         svc = list_entry(sdom->vcpu.next, struct rt_vcpu, sdom_elem);
-        op->u.rtds.period = svc->period / MICROSECS(1); /* transfer to us */
-        op->u.rtds.budget = svc->budget / MICROSECS(1);
+        op->u.d.rtds.period = svc->period / MICROSECS(1); /* transfer to us */
+        op->u.d.rtds.budget = svc->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 )
+        if ( op->u.d.rtds.period == 0 || op->u.d.rtds.budget == 0 )
         {
             rc = -EINVAL;
             break;
@@ -1105,8 +1105,8 @@ rt_dom_cntl(
         list_for_each( iter, &sdom->vcpu )
         {
             struct rt_vcpu * svc = list_entry(iter, struct rt_vcpu, sdom_elem);
-            svc->period = MICROSECS(op->u.rtds.period); /* transfer to nanosec */
-            svc->budget = MICROSECS(op->u.rtds.budget);
+            svc->period = MICROSECS(op->u.d.rtds.period); /* transfer to nanosec */
+            svc->budget = MICROSECS(op->u.d.rtds.budget);
         }
         spin_unlock_irqrestore(&prv->lock, flags);
         break;
diff --git a/xen/common/schedule.c b/xen/common/schedule.c
index f5a2e55..29f403c 100644
--- a/xen/common/schedule.c
+++ b/xen/common/schedule.c
@@ -65,7 +65,6 @@ DEFINE_PER_CPU(struct schedule_data, schedule_data);
 DEFINE_PER_CPU(struct scheduler *, scheduler);
 
 static const struct scheduler *schedulers[] = {
-    &sched_sedf_def,
     &sched_credit_def,
     &sched_credit2_def,
     &sched_arinc653_def,
diff --git a/xen/include/public/domctl.h b/xen/include/public/domctl.h
index 88f8002..c1e25f4 100644
--- a/xen/include/public/domctl.h
+++ b/xen/include/public/domctl.h
@@ -330,31 +330,50 @@ DEFINE_XEN_GUEST_HANDLE(xen_domctl_max_vcpus_t);
 #define XEN_SCHEDULER_ARINC653 7
 #define XEN_SCHEDULER_RTDS     8
 
+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 union xen_domctl_schedparam {
+    xen_domctl_sched_credit_t credit;
+    xen_domctl_sched_credit2_t credit2;
+    xen_domctl_sched_rtds_t rtds;
+} xen_domctl_schedparam_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;
+} xen_domctl_schedparam_vcpu_t;
+DEFINE_XEN_GUEST_HANDLE(xen_domctl_schedparam_vcpu_t);
+
 /* Set or get info? */
 #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_sedf {
-            uint64_aligned_t period;
-            uint64_aligned_t slice;
-            uint64_aligned_t latency;
-            uint32_t extratime;
-            uint32_t weight;
-        } sedf;
-        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_schedparam_t d;
+        struct {
+            XEN_GUEST_HANDLE_64(xen_domctl_schedparam_vcpu_t) vcpus;
+            uint16_t nr_vcpus;
+        } v;
     } u;
 };
 typedef struct xen_domctl_scheduler_op xen_domctl_scheduler_op_t;

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