[Xen-changelog] [xen-4.2-testing] scheduler: fix rate limit range checking

[Xen patchbot-4.2-testing <patchbot@xxxxxxx>]

# HG changeset patch
# User Jan Beulich <jbeulich@xxxxxxxx>
# Date 1357717998 -3600
# Node ID ef4f080bbeb573dd806c9d7cd3b4414cb274bfea
# Parent  18b56fd7dcb236d7e1fa2458e366df7863a945a5
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@xxxxxxxx>
Acked-by: Keir Fraser <keir@xxxxxxx>
xen-unstable changeset: 26266:8d209624ea83
xen-unstable date: Mon Dec 10 10:14:27 UTC 2012
---


diff -r 18b56fd7dcb2 -r ef4f080bbeb5 xen/common/sched_credit.c
--- a/xen/common/sched_credit.c Wed Jan 09 08:51:27 2013 +0100
+++ b/xen/common/sched_credit.c Wed Jan 09 08:53:18 2013 +0100
@@ -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 )
diff -r 18b56fd7dcb2 -r ef4f080bbeb5 xen/common/schedule.c
--- a/xen/common/schedule.c     Wed Jan 09 08:51:27 2013 +0100
+++ b/xen/common/schedule.c     Wed Jan 09 08:53:18 2013 +0100
@@ -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;

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