[Xen-changelog] [xen master] xen: sched: simplify ACPI S3 resume path.

[patchbot@xxxxxxx]

commit 8a5d50dd0b047d9f7fe49f511fc9f589073d93d6
Author:     Dario Faggioli <dario.faggioli@xxxxxxxxxx>
AuthorDate: Tue Jan 17 18:27:10 2017 +0100
Commit:     George Dunlap <george.dunlap@xxxxxxxxxx>
CommitDate: Tue Jan 24 17:02:07 2017 +0000

    xen: sched: simplify ACPI S3 resume path.
    
    In fact, when domains are being unpaused:
     - it's not necessary to put the vcpu to sleep, as
       they are all already paused;
     - it is not necessary to call vcpu_migrate(), as
       the vcpus are still paused, and therefore won't
       wakeup anyway.
    
    Basically, the only important thing is to call
    pick_cpu, to let the scheduler run and figure out
    what would be the best initial placement (i.e., the
    value stored in v->processor), for the vcpus, as
    they come back up, one after another.
    
    Note that this is consistent with what was happening
    before this change, as vcpu_migrate() calls pick_cpu.
    But much simpler and quicker.
    
    Signed-off-by: Dario Faggioli <dario.faggioli@xxxxxxxxxx>
    Reviewed-by: George Dunlap <george.dunlap@xxxxxxxxxx>
---
 xen/common/schedule.c | 22 ++++++++++------------
 1 file changed, 10 insertions(+), 12 deletions(-)

diff --git a/xen/common/schedule.c b/xen/common/schedule.c
index bee5d1f..43b5b99 100644
--- a/xen/common/schedule.c
+++ b/xen/common/schedule.c
@@ -635,7 +635,11 @@ void restore_vcpu_affinity(struct domain *d)
 
     for_each_vcpu ( d, v )
     {
-        spinlock_t *lock = vcpu_schedule_lock_irq(v);
+        spinlock_t *lock;
+
+        ASSERT(!vcpu_runnable(v));
+
+        lock = vcpu_schedule_lock_irq(v);
 
         if ( v->affinity_broken )
         {
@@ -659,17 +663,11 @@ void restore_vcpu_affinity(struct domain *d)
                     cpupool_domain_cpumask(v->domain));
         v->processor = cpumask_any(cpumask_scratch_cpu(cpu));
 
-        if ( v->processor == cpu )
-        {
-            set_bit(_VPF_migrating, &v->pause_flags);
-            spin_unlock_irq(lock);;
-            vcpu_sleep_nosync(v);
-            vcpu_migrate(v);
-        }
-        else
-        {
-            spin_unlock_irq(lock);
-        }
+        spin_unlock_irq(lock);;
+
+        lock = vcpu_schedule_lock_irq(v);
+        v->processor = SCHED_OP(VCPU2OP(v), pick_cpu, v);
+        spin_unlock_irq(lock);
     }
 
     domain_update_node_affinity(d);
--
generated by git-patchbot for /home/xen/git/xen.git#master

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