[Xen-changelog] [xen master] sched: avoid cpumasks on stack in sched/core.c

[patchbot@xxxxxxx]

commit e301cd9b0f05b0fe3f329a3bd3663618380a1310
Author:     Juergen Gross <jgross@xxxxxxxx>
AuthorDate: Fri Jan 24 10:30:05 2020 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Fri Jan 24 10:30:05 2020 +0100

    sched: avoid cpumasks on stack in sched/core.c
    
    There are still several instances of cpumask_t on the stack in
    scheduling code. Avoid them as far as possible.
    
    Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
    Reviewed-by: Dario Faggioli <dfaggioli@xxxxxxxx>
---
 xen/common/sched/core.c | 14 +++++---------
 1 file changed, 5 insertions(+), 9 deletions(-)

diff --git a/xen/common/sched/core.c b/xen/common/sched/core.c
index 944164d78a..73799c2508 100644
--- a/xen/common/sched/core.c
+++ b/xen/common/sched/core.c
@@ -1178,7 +1178,6 @@ int cpu_disable_scheduler(unsigned int cpu)
 {
     struct domain *d;
     const struct cpupool *c;
-    cpumask_t online_affinity;
     int ret = 0;
 
     rcu_read_lock(&sched_res_rculock);
@@ -1196,8 +1195,7 @@ int cpu_disable_scheduler(unsigned int cpu)
             unsigned long flags;
             spinlock_t *lock = unit_schedule_lock_irqsave(unit, &flags);
 
-            cpumask_and(&online_affinity, unit->cpu_hard_affinity, 
c->cpu_valid);
-            if ( cpumask_empty(&online_affinity) &&
+            if ( !cpumask_intersects(unit->cpu_hard_affinity, c->cpu_valid) &&
                  cpumask_test_cpu(cpu, unit->cpu_hard_affinity) )
             {
                 if ( sched_check_affinity_broken(unit) )
@@ -1336,12 +1334,10 @@ static int vcpu_set_affinity(
 
 int vcpu_set_hard_affinity(struct vcpu *v, const cpumask_t *affinity)
 {
-    cpumask_t online_affinity;
     cpumask_t *online;
 
     online = VCPU2ONLINE(v);
-    cpumask_and(&online_affinity, affinity, online);
-    if ( cpumask_empty(&online_affinity) )
+    if ( !cpumask_intersects(online, affinity) )
         return -EINVAL;
 
     return vcpu_set_affinity(v, affinity, v->sched_unit->cpu_hard_affinity);
@@ -2586,11 +2582,11 @@ static void schedule(void)
 
     if ( gran > 1 )
     {
-        cpumask_t mask;
+        cpumask_t *mask = cpumask_scratch_cpu(cpu);
 
         prev->rendezvous_in_cnt = gran;
-        cpumask_andnot(&mask, sr->cpus, cpumask_of(cpu));
-        cpumask_raise_softirq(&mask, SCHED_SLAVE_SOFTIRQ);
+        cpumask_andnot(mask, sr->cpus, cpumask_of(cpu));
+        cpumask_raise_softirq(mask, SCHED_SLAVE_SOFTIRQ);
         next = sched_wait_rendezvous_in(prev, &lock, cpu, now);
         if ( !next )
             return;
--
generated by git-patchbot for /home/xen/git/xen.git#master

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