scheduler: fix rate limit range checking

For one, neither of the two checks permitted for the documented value
of zero (disabling the functionality altogether).

Second, the range checking of the command line parameter was done by
the credit scheduler's initialization code, despite it being a generic
scheduler option.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Keir Fraser <keir@xen.org>

diff --git a/xen/common/sched_credit.c b/xen/common/sched_credit.c
index c42ff0e073e322c912aea919914eea242c29045b..db31f1b8e789811b6c1b45e3175ea7479e18b3a6 100644 (file)
--- a/xen/common/sched_credit.c
+++ b/xen/common/sched_credit.c
@@ -835,8 +835,9 @@ csched_sys_cntl(const struct scheduler *ops,
     case XEN_SYSCTL_SCHEDOP_putinfo:
         if (params->tslice_ms > XEN_SYSCTL_CSCHED_TSLICE_MAX
             || params->tslice_ms < XEN_SYSCTL_CSCHED_TSLICE_MIN 
-            || params->ratelimit_us > XEN_SYSCTL_SCHED_RATELIMIT_MAX
-            || params->ratelimit_us < XEN_SYSCTL_SCHED_RATELIMIT_MIN 
+            || (params->ratelimit_us
+                && (params->ratelimit_us > XEN_SYSCTL_SCHED_RATELIMIT_MAX
+                    || params->ratelimit_us < XEN_SYSCTL_SCHED_RATELIMIT_MIN))
             || MICROSECS(params->ratelimit_us) > MILLISECS(params->tslice_ms) )
                 goto out;
         prv->tslice_ms = params->tslice_ms;
@@ -1593,17 +1594,6 @@ csched_init(struct scheduler *ops)
         sched_credit_tslice_ms = CSCHED_DEFAULT_TSLICE_MS;
     }
 
-    if ( sched_ratelimit_us > XEN_SYSCTL_SCHED_RATELIMIT_MAX
-         || sched_ratelimit_us < XEN_SYSCTL_SCHED_RATELIMIT_MIN )
-    {
-        printk("WARNING: sched_ratelimit_us outside of valid range [%d,%d].\n"
-               " Resetting to default %u\n",
-               XEN_SYSCTL_SCHED_RATELIMIT_MIN,
-               XEN_SYSCTL_SCHED_RATELIMIT_MAX,
-               SCHED_DEFAULT_RATELIMIT_US);
-        sched_ratelimit_us = SCHED_DEFAULT_RATELIMIT_US;
-    }
-
     prv->tslice_ms = sched_credit_tslice_ms;
     prv->ticks_per_tslice = CSCHED_TICKS_PER_TSLICE;
     if ( prv->tslice_ms < prv->ticks_per_tslice )

diff --git a/xen/common/schedule.c b/xen/common/schedule.c
index 231e0974759c2f258766fd6446519b8e38635b6b..ae798c95dc7f4b44338113a932ae293c7dc97bbe 100644 (file)
--- a/xen/common/schedule.c
+++ b/xen/common/schedule.c
@@ -1324,6 +1324,18 @@ void __init scheduler_init(void)
     if ( SCHED_OP(&ops, init) )
         panic("scheduler returned error on init\n");
 
+    if ( sched_ratelimit_us &&
+         (sched_ratelimit_us > XEN_SYSCTL_SCHED_RATELIMIT_MAX
+          || sched_ratelimit_us < XEN_SYSCTL_SCHED_RATELIMIT_MIN) )
+    {
+        printk("WARNING: sched_ratelimit_us outside of valid range [%d,%d].\n"
+               " Resetting to default %u\n",
+               XEN_SYSCTL_SCHED_RATELIMIT_MIN,
+               XEN_SYSCTL_SCHED_RATELIMIT_MAX,
+               SCHED_DEFAULT_RATELIMIT_US);
+        sched_ratelimit_us = SCHED_DEFAULT_RATELIMIT_US;
+    }
+
     idle_domain = domain_create(DOMID_IDLE, 0, 0);
     BUG_ON(IS_ERR(idle_domain));
     idle_domain->vcpu = idle_vcpu;