[Xen-devel] [PATCH] xen: recalculate per-cpupool credits when updating timeslice

[Juergen Gross <jgross@xxxxxxxx>]

When modifying the timeslice of the credit scheduler in a cpupool the
cpupool global credit value (n_cpus * credits_per_tslice) isn't
recalculated. This will lead to wrong scheduling decisions later.

Do the recalculation when updating the timeslice.

Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
---
 xen/common/sched_credit.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/xen/common/sched_credit.c b/xen/common/sched_credit.c
index 03fb2c2..912511e 100644
--- a/xen/common/sched_credit.c
+++ b/xen/common/sched_credit.c
@@ -1086,12 +1086,19 @@ csched_dom_cntl(
 static inline void
 __csched_set_tslice(struct csched_private *prv, unsigned timeslice)
 {
+    unsigned long flags;
+
+    spin_lock_irqsave(&prv->lock, flags);
+
     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;
+    prv->credit = prv->credits_per_tslice * prv->ncpus;
+
+    spin_unlock_irqrestore(&prv->lock, flags);
 }
 
 static int
-- 
2.6.2


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