xen: libxc: allow to set the ratelimit value online

The main purpose of the patch is to provide the xen-libxc
plumbing necessary to be able to change the value of the
ratelimit_us parameter online, for Credit2 (like it is
already for Credit1).

While there:
 - mention in the Xen logs when rate limiting was enables
   and is being disabled (and vice-versa);
 - fix csched2_sys_cntl() which was always returning
   -EINVAL in the XEN_SYSCTL_SCHEDOP_putinfo case.

And also:
 - fix style of an if in csched_sys_cntl();
 - fix the style of the switch in csched2_sys_cntl();

Signed-off-by: Dario Faggioli <dario.faggioli@citrix.com>
Reviewed-by: George Dunlap <george.dunlap@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>

diff --git a/tools/libxc/include/xenctrl.h b/tools/libxc/include/xenctrl.h
index 5e685a68258971ba241eec4feb01392c05c1dcc1..167fc5bd7807480392a5b871a9791b556de96a63 100644 (file)
--- a/tools/libxc/include/xenctrl.h
+++ b/tools/libxc/include/xenctrl.h
@@ -910,25 +910,31 @@ int xc_sched_credit_domain_get(xc_interface *xch,
                                uint32_t domid,
                                struct xen_domctl_sched_credit *sdom);
 int xc_sched_credit_params_set(xc_interface *xch,
-                              uint32_t cpupool_id,
-                              struct xen_sysctl_credit_schedule *schedule);
+                               uint32_t cpupool_id,
+                               struct xen_sysctl_credit_schedule *schedule);
 int xc_sched_credit_params_get(xc_interface *xch,
-                              uint32_t cpupool_id,
-                              struct xen_sysctl_credit_schedule *schedule);
+                               uint32_t cpupool_id,
+                               struct xen_sysctl_credit_schedule *schedule);
+
+int xc_sched_credit2_params_set(xc_interface *xch,
+                                uint32_t cpupool_id,
+                                struct xen_sysctl_credit2_schedule *schedule);
+int xc_sched_credit2_params_get(xc_interface *xch,
+                                uint32_t cpupool_id,
+                                struct xen_sysctl_credit2_schedule *schedule);
 int xc_sched_credit2_domain_set(xc_interface *xch,
-                               uint32_t domid,
-                               struct xen_domctl_sched_credit2 *sdom);
-
+                                uint32_t domid,
+                                struct xen_domctl_sched_credit2 *sdom);
 int xc_sched_credit2_domain_get(xc_interface *xch,
-                               uint32_t domid,
-                               struct xen_domctl_sched_credit2 *sdom);
+                                uint32_t domid,
+                                struct xen_domctl_sched_credit2 *sdom);
 
 int xc_sched_rtds_domain_set(xc_interface *xch,
-                            uint32_t domid,
-                            struct xen_domctl_sched_rtds *sdom);
+                             uint32_t domid,
+                             struct xen_domctl_sched_rtds *sdom);
 int xc_sched_rtds_domain_get(xc_interface *xch,
-                            uint32_t domid,
-                            struct xen_domctl_sched_rtds *sdom);
+                             uint32_t domid,
+                             struct xen_domctl_sched_rtds *sdom);
 int xc_sched_rtds_vcpu_set(xc_interface *xch,
                            uint32_t domid,
                            struct xen_domctl_schedparam_vcpu *vcpus,

diff --git a/tools/libxc/xc_csched2.c b/tools/libxc/xc_csched2.c
index ed996055f66a62c39b588c9b926e91262c35e31e..5b62a5f126c7addd1fb2839110ceed12fb53d33f 100644 (file)
--- a/tools/libxc/xc_csched2.c
+++ b/tools/libxc/xc_csched2.c
@@ -60,3 +60,47 @@ xc_sched_credit2_domain_get(
 
     return err;
 }
+
+int
+xc_sched_credit2_params_set(
+    xc_interface *xch,
+    uint32_t cpupool_id,
+    struct xen_sysctl_credit2_schedule *schedule)
+{
+    DECLARE_SYSCTL;
+
+    sysctl.cmd = XEN_SYSCTL_scheduler_op;
+    sysctl.u.scheduler_op.cpupool_id = cpupool_id;
+    sysctl.u.scheduler_op.sched_id = XEN_SCHEDULER_CREDIT2;
+    sysctl.u.scheduler_op.cmd = XEN_SYSCTL_SCHEDOP_putinfo;
+
+    sysctl.u.scheduler_op.u.sched_credit2 = *schedule;
+
+    if ( do_sysctl(xch, &sysctl) )
+        return -1;
+
+    *schedule = sysctl.u.scheduler_op.u.sched_credit2;
+
+    return 0;
+}
+
+int
+xc_sched_credit2_params_get(
+    xc_interface *xch,
+    uint32_t cpupool_id,
+    struct xen_sysctl_credit2_schedule *schedule)
+{
+    DECLARE_SYSCTL;
+
+    sysctl.cmd = XEN_SYSCTL_scheduler_op;
+    sysctl.u.scheduler_op.cpupool_id = cpupool_id;
+    sysctl.u.scheduler_op.sched_id = XEN_SCHEDULER_CREDIT2;
+    sysctl.u.scheduler_op.cmd = XEN_SYSCTL_SCHEDOP_getinfo;
+
+    if ( do_sysctl(xch, &sysctl) )
+        return -1;
+
+    *schedule = sysctl.u.scheduler_op.u.sched_credit2;
+
+    return 0;
+}

diff --git a/xen/common/sched_credit.c b/xen/common/sched_credit.c
index 16325b5f07b986c6ca300b52bdf08cc1dc8a010f..b63efacc6a38d183a10c2ccbea70437242a2c672 100644 (file)
--- a/xen/common/sched_credit.c
+++ b/xen/common/sched_credit.c
@@ -1226,16 +1226,20 @@ csched_sys_cntl(const struct scheduler *ops,
     switch ( sc->cmd )
     {
     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
-                && (params->ratelimit_us > XEN_SYSCTL_SCHED_RATELIMIT_MAX
-                    || params->ratelimit_us < XEN_SYSCTL_SCHED_RATELIMIT_MIN))
-            || MICROSECS(params->ratelimit_us) > MILLISECS(params->tslice_ms) )
+        if ( params->tslice_ms > XEN_SYSCTL_CSCHED_TSLICE_MAX
+             || params->tslice_ms < XEN_SYSCTL_CSCHED_TSLICE_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;
 
         spin_lock_irqsave(&prv->lock, flags);
         __csched_set_tslice(prv, params->tslice_ms);
+        if ( !prv->ratelimit_us && params->ratelimit_us )
+            printk(XENLOG_INFO "Enabling context switch rate limiting\n");
+        else if ( prv->ratelimit_us && !params->ratelimit_us )
+            printk(XENLOG_INFO "Disabling context switch rate limiting\n");
         prv->ratelimit_us = params->ratelimit_us;
         spin_unlock_irqrestore(&prv->lock, flags);
 

diff --git a/xen/common/sched_credit2.c b/xen/common/sched_credit2.c
index 12dfd20a4c461131e9c897637ae88b431a176ca0..5c7d0dc5e10d6b142b71d4d303553b899ff0bbb3 100644 (file)
--- a/xen/common/sched_credit2.c
+++ b/xen/common/sched_credit2.c
@@ -1988,29 +1988,33 @@ csched2_dom_cntl(
 static int csched2_sys_cntl(const struct scheduler *ops,
                             struct xen_sysctl_scheduler_op *sc)
 {
-    int rc = -EINVAL;
-    xen_sysctl_credit_schedule_t *params = &sc->u.sched_credit;
+    xen_sysctl_credit2_schedule_t *params = &sc->u.sched_credit2;
     struct csched2_private *prv = CSCHED2_PRIV(ops);
     unsigned long flags;
 
     switch (sc->cmd )
     {
-        case XEN_SYSCTL_SCHEDOP_putinfo:
-            if ( params->ratelimit_us &&
-                ( params->ratelimit_us > XEN_SYSCTL_SCHED_RATELIMIT_MAX ||
-                  params->ratelimit_us < XEN_SYSCTL_SCHED_RATELIMIT_MIN ))
-                return rc;
-            write_lock_irqsave(&prv->lock, flags);
-            prv->ratelimit_us = params->ratelimit_us;
-            write_unlock_irqrestore(&prv->lock, flags);
-            break;
-
-        case XEN_SYSCTL_SCHEDOP_getinfo:
-            params->ratelimit_us = prv->ratelimit_us;
-            rc = 0;
-            break;
+    case XEN_SYSCTL_SCHEDOP_putinfo:
+        if ( params->ratelimit_us &&
+             (params->ratelimit_us > XEN_SYSCTL_SCHED_RATELIMIT_MAX ||
+              params->ratelimit_us < XEN_SYSCTL_SCHED_RATELIMIT_MIN ))
+            return -EINVAL;
+
+        write_lock_irqsave(&prv->lock, flags);
+        if ( !prv->ratelimit_us && params->ratelimit_us )
+            printk(XENLOG_INFO "Enabling context switch rate limiting\n");
+        else if ( prv->ratelimit_us && !params->ratelimit_us )
+            printk(XENLOG_INFO "Disabling context switch rate limiting\n");
+        prv->ratelimit_us = params->ratelimit_us;
+        write_unlock_irqrestore(&prv->lock, flags);
+
+    /* FALLTHRU */
+    case XEN_SYSCTL_SCHEDOP_getinfo:
+        params->ratelimit_us = prv->ratelimit_us;
+        break;
     }
-    return rc;
+
+    return 0;
 }
 
 static void *

diff --git a/xen/include/public/sysctl.h b/xen/include/public/sysctl.h
index 8197c14283f03b179bca007c5a25345fe38c3790..fd0fa671a60f5be56c292b5b6e0138b41cf6a242 100644 (file)
--- a/xen/include/public/sysctl.h
+++ b/xen/include/public/sysctl.h
@@ -623,19 +623,29 @@ struct xen_sysctl_arinc653_schedule {
 typedef struct xen_sysctl_arinc653_schedule xen_sysctl_arinc653_schedule_t;
 DEFINE_XEN_GUEST_HANDLE(xen_sysctl_arinc653_schedule_t);
 
+/*
+ * Valid range for context switch rate limit (in microseconds).
+ * Applicable to Credit and Credit2 schedulers.
+ */
+#define XEN_SYSCTL_SCHED_RATELIMIT_MAX 500000
+#define XEN_SYSCTL_SCHED_RATELIMIT_MIN 100
+
 struct xen_sysctl_credit_schedule {
     /* Length of timeslice in milliseconds */
 #define XEN_SYSCTL_CSCHED_TSLICE_MAX 1000
 #define XEN_SYSCTL_CSCHED_TSLICE_MIN 1
     unsigned tslice_ms;
-    /* Rate limit (minimum timeslice) in microseconds */
-#define XEN_SYSCTL_SCHED_RATELIMIT_MAX 500000
-#define XEN_SYSCTL_SCHED_RATELIMIT_MIN 100
     unsigned ratelimit_us;
 };
 typedef struct xen_sysctl_credit_schedule xen_sysctl_credit_schedule_t;
 DEFINE_XEN_GUEST_HANDLE(xen_sysctl_credit_schedule_t);
 
+struct xen_sysctl_credit2_schedule {
+    unsigned ratelimit_us;
+};
+typedef struct xen_sysctl_credit2_schedule xen_sysctl_credit2_schedule_t;
+DEFINE_XEN_GUEST_HANDLE(xen_sysctl_credit2_schedule_t);
+
 /* XEN_SYSCTL_scheduler_op */
 /* Set or get info? */
 #define XEN_SYSCTL_SCHEDOP_putinfo 0
@@ -649,6 +659,7 @@ struct xen_sysctl_scheduler_op {
             XEN_GUEST_HANDLE_64(xen_sysctl_arinc653_schedule_t) schedule;
         } sched_arinc653;
         struct xen_sysctl_credit_schedule sched_credit;
+        struct xen_sysctl_credit2_schedule sched_credit2;
     } u;
 };
 typedef struct xen_sysctl_scheduler_op xen_sysctl_scheduler_op_t;