File 5aeaeae4-introduce-vcpu_sleep_nosync_locked.patch of Package xen

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File 5aeaeae4-introduce-vcpu_sleep_nosync_locked.patch of Package xen (Revision d85eb8b52b5781ff09d3eea10de3b512)

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# Commit da0a5e00de8aa93f2a7482d138dbee9dec2aa5c2
# Date 2018-05-03 11:56:36 +0100
# Author George Dunlap <george.dunlap@citrix.com>
# Committer George Dunlap <george.dunlap@citrix.com>
xen: Introduce vcpu_sleep_nosync_locked()

There are a lot of places which release a lock before calling
vcpu_sleep_nosync(), which then just grabs the lock again.  This is
not only a waste of time, but leads to more code duplication (since
you have to copy-and-paste recipes rather than calling a unified
function), which in turn leads to an increased chance of bugs.

Introduce vcpu_sleep_nosync_locked(), which can be called if you
already hold the schedule lock.

Signed-off-by: George Dunlap <george.dunlap@citrix.com>
Reviewed-by: Dario Faggioli <dfaggioli@suse.com>

--- a/xen/common/schedule.c
+++ b/xen/common/schedule.c
@@ -436,14 +436,9 @@ void sched_destroy_domain(struct domain
     cpupool_rm_domain(d);
 }
 
-void vcpu_sleep_nosync(struct vcpu *v)
+void vcpu_sleep_nosync_locked(struct vcpu *v)
 {
-    unsigned long flags;
-    spinlock_t *lock;
-
-    TRACE_2D(TRC_SCHED_SLEEP, v->domain->domain_id, v->vcpu_id);
-
-    lock = vcpu_schedule_lock_irqsave(v, &flags);
+    ASSERT(spin_is_locked(per_cpu(schedule_data,v->processor).schedule_lock));
 
     if ( likely(!vcpu_runnable(v)) )
     {
@@ -452,6 +447,18 @@ void vcpu_sleep_nosync(struct vcpu *v)
 
         SCHED_OP(vcpu_scheduler(v), sleep, v);
     }
+}
+
+void vcpu_sleep_nosync(struct vcpu *v)
+{
+    unsigned long flags;
+    spinlock_t *lock;
+
+    TRACE_2D(TRC_SCHED_SLEEP, v->domain->domain_id, v->vcpu_id);
+
+    lock = vcpu_schedule_lock_irqsave(v, &flags);
+
+    vcpu_sleep_nosync_locked(v);
 
     vcpu_schedule_unlock_irqrestore(lock, flags, v);
 }

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File 5aeaeae4-introduce-vcpu_sleep_nosync_locked.patch of Package xen (Revision d85eb8b52b5781ff09d3eea10de3b512)

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