futex: Take mmap_sem for get_user_pages in fault_in_user_writeable

[firefly-linux-kernel-4.4.55.git] / kernel / sched_fair.c

diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index 37087a7fac220e72cc6b6e63ba5a8f4dc83299d2..5488a5d3bc0ed439ea81b3cfed2fb5e54c05790e 100644 (file)
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -1398,11 +1398,38 @@ static int select_task_rq_fair(struct task_struct *p, int sd_flag, int wake_flag
                                want_sd = 0;
                }
 
-               if (want_affine && (tmp->flags & SD_WAKE_AFFINE) &&
-                   cpumask_test_cpu(prev_cpu, sched_domain_span(tmp))) {
+               if (want_affine && (tmp->flags & SD_WAKE_AFFINE)) {
+                       int candidate = -1, i;
 
-                       affine_sd = tmp;
-                       want_affine = 0;
+                       if (cpumask_test_cpu(prev_cpu, sched_domain_span(tmp)))
+                               candidate = cpu;
+
+                       /*
+                        * Check for an idle shared cache.
+                        */
+                       if (tmp->flags & SD_PREFER_SIBLING) {
+                               if (candidate == cpu) {
+                                       if (!cpu_rq(prev_cpu)->cfs.nr_running)
+                                               candidate = prev_cpu;
+                               }
+
+                               if (candidate == -1 || candidate == cpu) {
+                                       for_each_cpu(i, sched_domain_span(tmp)) {
+                                               if (!cpumask_test_cpu(i, &p->cpus_allowed))
+                                                       continue;
+                                               if (!cpu_rq(i)->cfs.nr_running) {
+                                                       candidate = i;
+                                                       break;
+                                               }
+                                       }
+                               }
+                       }
+
+                       if (candidate >= 0) {
+                               affine_sd = tmp;
+                               want_affine = 0;
+                               cpu = candidate;
+                       }
                }
 
                if (!want_sd && !want_affine)