[Xen-changelog] [xen stable-4.2] credit: Update other parameters when setting tslice_ms

[patchbot@xxxxxxx]

commit 88f72c707e9588c60a81cb8a917b0a2b1d5aa1a1
Author:     Nate Studer <nate.studer@xxxxxxxxxxxxxxx>
AuthorDate: Mon Dec 2 15:51:00 2013 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Mon Dec 2 15:51:00 2013 +0100

    credit: Update other parameters when setting tslice_ms
    
    Add a utility function to update the rest of the timeslice
    accounting fields when updating the timeslice of the
    credit scheduler, so that capped CPUs behave correctly.
    
    Before this patch changing the timeslice to a value higher
    than the default would result in a domain not utilizing
    its full capacity and changing the timeslice to a value
    lower than the default would result in a domain exceeding
    its capacity.
    
    Signed-off-by: Nate Studer <nate.studer@xxxxxxxxxxxxxxx>
    Reviewed-by: Dario Faggioli <dario.faggioli@xxxxxxxxxx>
    Reviewed-by: George Dunlap <george.dunlap@xxxxxxxxxxxxx>
    master commit: 1320b8100c2ed390fc640557a050f5c700d8338d
    master date: 2013-11-15 17:38:10 +0100
---
 xen/common/sched_credit.c |   20 +++++++++++++-------
 1 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/xen/common/sched_credit.c b/xen/common/sched_credit.c
index ee3df06..5195442 100644
--- a/xen/common/sched_credit.c
+++ b/xen/common/sched_credit.c
@@ -847,6 +847,17 @@ csched_dom_cntl(
     return 0;
 }
 
+static inline void
+__csched_set_tslice(struct csched_private *prv, unsigned timeslice)
+{
+    prv->tslice_ms = timeslice;
+    prv->ticks_per_tslice = CSCHED_TICKS_PER_TSLICE;
+    if ( prv->tslice_ms < prv->ticks_per_tslice )
+        prv->ticks_per_tslice = 1;
+    prv->tick_period_us = prv->tslice_ms * 1000 / prv->ticks_per_tslice;
+    prv->credits_per_tslice = CSCHED_CREDITS_PER_MSEC * prv->tslice_ms;
+}
+
 static int
 csched_sys_cntl(const struct scheduler *ops,
                         struct xen_sysctl_scheduler_op *sc)
@@ -865,7 +876,7 @@ csched_sys_cntl(const struct scheduler *ops,
                     || params->ratelimit_us < XEN_SYSCTL_SCHED_RATELIMIT_MIN))
             || MICROSECS(params->ratelimit_us) > MILLISECS(params->tslice_ms) )
                 goto out;
-        prv->tslice_ms = params->tslice_ms;
+        __csched_set_tslice(prv, params->tslice_ms);
         prv->ratelimit_us = params->ratelimit_us;
         /* FALLTHRU */
     case XEN_SYSCTL_SCHEDOP_getinfo:
@@ -1623,12 +1634,7 @@ csched_init(struct scheduler *ops)
         sched_credit_tslice_ms = CSCHED_DEFAULT_TSLICE_MS;
     }
 
-    prv->tslice_ms = sched_credit_tslice_ms;
-    prv->ticks_per_tslice = CSCHED_TICKS_PER_TSLICE;
-    if ( prv->tslice_ms < prv->ticks_per_tslice )
-        prv->ticks_per_tslice = 1;
-    prv->tick_period_us = prv->tslice_ms * 1000 / prv->ticks_per_tslice;
-    prv->credits_per_tslice = CSCHED_CREDITS_PER_MSEC * prv->tslice_ms;
+    __csched_set_tslice(prv, sched_credit_tslice_ms);
 
     if ( MICROSECS(sched_ratelimit_us) > MILLISECS(sched_credit_tslice_ms) )
     {
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.2

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