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SubjectRe: [PATCH tip/core/rcu 06/45] torture: Intensify locking test
On Mon, Apr 28, 2014 at 05:24:54PM -0700, Paul E. McKenney wrote:
> From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
>
> The current lock_torture_writer() spends too much time sleeping and not
> enough time hammering locks, as in an eight-CPU test will often only be
> utilizing a CPU or two. This commit therefore makes lock_torture_writer()
> sleep less and hammer more.
>
> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
> ---
> kernel/locking/locktorture.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c
> index f26b1a18e34e..b0d3e3c50672 100644
> --- a/kernel/locking/locktorture.c
> +++ b/kernel/locking/locktorture.c
> @@ -219,7 +219,8 @@ static int lock_torture_writer(void *arg)
> set_user_nice(current, 19);
>
> do {
> - schedule_timeout_uninterruptible(1);
> + if ((torture_random(&rand) & 0xfffff) == 0)
> + schedule_timeout_uninterruptible(1);

That's a one-in-1048576 chance of sleeping for a jiffy; is that frequent
enough to even bother sleeping at all?

> cur_ops->writelock();
> if (WARN_ON_ONCE(lock_is_write_held))
> lwsp->n_write_lock_fail++;
> --
> 1.8.1.5
>


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