AcoSail/kernel_optimize_test
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sched: convert sys_sched_getaffinity() to cpumask_var_t.

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Impact: stack usage reduction

Dynamically allocating cpumasks (when CONFIG_CPUMASK_OFFSTACK) saves
space in the stack.  cpumask_var_t is just a struct cpumask for
!CONFIG_CPUMASK_OFFSTACK.

Some jiggling here to make sure we always exit at the bottom (so we hit
the free_cpumask_var there).

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Rusty Russell 2008-11-25 02:35:11 +10:30 committed by Ingo Molnar
parent a0e902452d
commit f17c860760
1 changed files with 13 additions and 8 deletions
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21
kernel/sched.c
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@ -5499,19 +5499,24 @@ asmlinkage long sys_sched_getaffinity(pid_t pid, unsigned int len,
unsigned long __user *user_mask_ptr)
{
int ret;
cpumask_t mask;
cpumask_var_t mask;
if (len < sizeof(cpumask_t))
if (len < cpumask_size())
return -EINVAL;
ret = sched_getaffinity(pid, &mask);
if (ret < 0)
return ret;
if (!alloc_cpumask_var(&mask, GFP_KERNEL))
return -ENOMEM;
if (copy_to_user(user_mask_ptr, &mask, sizeof(cpumask_t)))
return -EFAULT;
ret = sched_getaffinity(pid, mask);
if (ret == 0) {
if (copy_to_user(user_mask_ptr, mask, cpumask_size()))
ret = -EFAULT;
else
ret = cpumask_size();
}
free_cpumask_var(mask);
return sizeof(cpumask_t);
return ret;
}
/**