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sched: convert struct (sys_)sched_setaffinity() to cpumask_var_t.
Impact: stack usage reduction Dynamically allocating cpumasks (when CONFIG_CPUMASK_OFFSTACK) saves space on the stack. cpumask_var_t is just a struct cpumask for !CONFIG_CPUMASK_OFFSTACK. Note the removal of the initializer of new_mask: since the first thing we did was "cpus_and(new_mask, new_mask, cpus_allowed)" I just changed that to "cpumask_and(new_mask, in_mask, cpus_allowed);". Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Ingo Molnar <mingo@elte.hu>
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parent
e76bd8d985
commit
5a16f3d30c
1 changed files with 27 additions and 13 deletions
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@ -5378,8 +5378,7 @@ asmlinkage long sys_sched_getparam(pid_t pid, struct sched_param __user *param)
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long sched_setaffinity(pid_t pid, const cpumask_t *in_mask)
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{
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cpumask_t cpus_allowed;
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cpumask_t new_mask = *in_mask;
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cpumask_var_t cpus_allowed, new_mask;
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struct task_struct *p;
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int retval;
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@ -5401,6 +5400,14 @@ long sched_setaffinity(pid_t pid, const cpumask_t *in_mask)
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get_task_struct(p);
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read_unlock(&tasklist_lock);
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if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL)) {
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retval = -ENOMEM;
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goto out_put_task;
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}
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if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) {
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retval = -ENOMEM;
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goto out_free_cpus_allowed;
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}
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retval = -EPERM;
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if ((current->euid != p->euid) && (current->euid != p->uid) &&
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!capable(CAP_SYS_NICE))
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@ -5410,24 +5417,28 @@ long sched_setaffinity(pid_t pid, const cpumask_t *in_mask)
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if (retval)
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goto out_unlock;
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cpuset_cpus_allowed(p, &cpus_allowed);
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cpus_and(new_mask, new_mask, cpus_allowed);
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cpuset_cpus_allowed(p, cpus_allowed);
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cpumask_and(new_mask, in_mask, cpus_allowed);
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again:
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retval = set_cpus_allowed_ptr(p, &new_mask);
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retval = set_cpus_allowed_ptr(p, new_mask);
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if (!retval) {
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cpuset_cpus_allowed(p, &cpus_allowed);
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if (!cpus_subset(new_mask, cpus_allowed)) {
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cpuset_cpus_allowed(p, cpus_allowed);
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if (!cpumask_subset(new_mask, cpus_allowed)) {
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/*
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* We must have raced with a concurrent cpuset
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* update. Just reset the cpus_allowed to the
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* cpuset's cpus_allowed
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*/
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new_mask = cpus_allowed;
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cpumask_copy(new_mask, cpus_allowed);
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goto again;
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}
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}
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out_unlock:
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free_cpumask_var(new_mask);
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out_free_cpus_allowed:
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free_cpumask_var(cpus_allowed);
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out_put_task:
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put_task_struct(p);
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put_online_cpus();
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return retval;
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@ -5453,14 +5464,17 @@ static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len,
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asmlinkage long sys_sched_setaffinity(pid_t pid, unsigned int len,
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unsigned long __user *user_mask_ptr)
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{
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cpumask_t new_mask;
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cpumask_var_t new_mask;
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int retval;
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retval = get_user_cpu_mask(user_mask_ptr, len, &new_mask);
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if (retval)
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return retval;
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if (!alloc_cpumask_var(&new_mask, GFP_KERNEL))
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return -ENOMEM;
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return sched_setaffinity(pid, &new_mask);
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retval = get_user_cpu_mask(user_mask_ptr, len, new_mask);
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if (retval == 0)
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retval = sched_setaffinity(pid, new_mask);
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free_cpumask_var(new_mask);
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return retval;
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}
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long sched_getaffinity(pid_t pid, cpumask_t *mask)
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