diff options
| -rw-r--r-- | kernel/sched.c | 45 |
1 files changed, 23 insertions, 22 deletions
diff --git a/kernel/sched.c b/kernel/sched.c index 33d7965f63f0..63e55ac242d1 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -2322,7 +2322,7 @@ void task_oncpu_function_call(struct task_struct *p, * * - fork, @p is stable because it isn't on the tasklist yet * - * - exec, @p is unstable XXX + * - exec, @p is unstable, retry loop * * - wake-up, we serialize ->cpus_allowed against TASK_WAKING so * we should be good. @@ -3132,21 +3132,36 @@ static void double_rq_unlock(struct rq *rq1, struct rq *rq2) } /* - * If dest_cpu is allowed for this process, migrate the task to it. - * This is accomplished by forcing the cpu_allowed mask to only - * allow dest_cpu, which will force the cpu onto dest_cpu. Then - * the cpu_allowed mask is restored. + * sched_exec - execve() is a valuable balancing opportunity, because at + * this point the task has the smallest effective memory and cache footprint. */ -static void sched_migrate_task(struct task_struct *p, int dest_cpu) +void sched_exec(void) { + struct task_struct *p = current; struct migration_req req; + int dest_cpu, this_cpu; unsigned long flags; struct rq *rq; +again: + this_cpu = get_cpu(); + dest_cpu = select_task_rq(p, SD_BALANCE_EXEC, 0); + if (dest_cpu == this_cpu) { + put_cpu(); + return; + } + rq = task_rq_lock(p, &flags); + put_cpu(); + + /* + * select_task_rq() can race against ->cpus_allowed + */ if (!cpumask_test_cpu(dest_cpu, &p->cpus_allowed) - || unlikely(!cpu_active(dest_cpu))) - goto out; + || unlikely(!cpu_active(dest_cpu))) { + task_rq_unlock(rq, &flags); + goto again; + } /* force the process onto the specified CPU */ if (migrate_task(p, dest_cpu, &req)) { @@ -3161,24 +3176,10 @@ static void sched_migrate_task(struct task_struct *p, int dest_cpu) return; } -out: task_rq_unlock(rq, &flags); } /* - * sched_exec - execve() is a valuable balancing opportunity, because at - * this point the task has the smallest effective memory and cache footprint. - */ -void sched_exec(void) -{ - int new_cpu, this_cpu = get_cpu(); - new_cpu = select_task_rq(current, SD_BALANCE_EXEC, 0); - put_cpu(); - if (new_cpu != this_cpu) - sched_migrate_task(current, new_cpu); -} - -/* * pull_task - move a task from a remote runqueue to the local runqueue. * Both runqueues must be locked. */ |