On Sat, Nov 02, 2019 at 12:45:55PM +0000, Lai Jiangshan wrote:
> ->read_read_unlock_special.b.deferred_qs is set when
> ->read_read_unlock_special is non-zero, and it is cleared when
> ->read_read_unlock_special is cleared.
>
> So it is useless.
>
> Signed-off-by: Lai Jiangshan <laijs@xxxxxxxxxxxxxxxxx>
I have queued this on -rcu for further review and testing, thank you!
Thanx, Paul
> ---
> include/linux/sched.h | 2 +-
> kernel/rcu/tree_plugin.h | 1 -
> 2 files changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/include/linux/sched.h b/include/linux/sched.h
> index 2c2e56bd8913..3ba392d71de9 100644
> --- a/include/linux/sched.h
> +++ b/include/linux/sched.h
> @@ -604,7 +604,7 @@ union rcu_special {
> u8 blocked;
> u8 need_qs;
> u8 exp_hint; /* Hint for performance. */
> - u8 deferred_qs;
> + u8 pad; /* No garbage from compiler! */
> } b; /* Bits. */
> u32 s; /* Set of bits. */
> };
> diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
> index 2fab8be2061f..f2fd7d687bdb 100644
> --- a/kernel/rcu/tree_plugin.h
> +++ b/kernel/rcu/tree_plugin.h
> @@ -622,7 +622,6 @@ static void rcu_read_unlock_special(struct task_struct *t)
> irq_work_queue_on(&rdp->defer_qs_iw, rdp->cpu);
> }
> }
> - t->rcu_read_unlock_special.b.deferred_qs = true;
> local_irq_restore(flags);
> return;
> }
> --
> 2.20.1
>
