# HG changeset patch
# User Jan Beulich <jbeulich@suse.com>
# Date 1355134467 -3600
# Node ID 8d209624ea83b272e1ebd713a928c38d4782f4f1
# Parent  f96a0cda12160f497981a37f6922a1ed7db9a462
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>

--- a/xen/common/sched_credit.c
+++ b/xen/common/sched_credit.c
@@ -846,8 +846,9 @@ csched_sys_cntl(const struct scheduler *
     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;
@@ -1607,17 +1608,6 @@ 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 )
--- a/xen/common/schedule.c
+++ b/xen/common/schedule.c
@@ -1322,6 +1322,18 @@ 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;