On 11/10/10 15:07, Paul E. McKenney wrote:
> On Wed, Nov 10, 2010 at 09:19:26AM -0800, Randy Dunlap wrote:
>> On Wed, 10 Nov 2010 14:07:19 +1100 Stephen Rothwell wrote:
>>
>>> Hi all,
>>>
>>> Changes since 20101109:
>>
>>
>> when CONFIG_RCU_BOOST is not enabled:
>>
>> In file included from linux-next-20101110/kernel/rcutiny.c:53:
>> linux-next-20101110/kernel/rcutiny_plugin.h: In function 'rcu_preempt_cpu_qs':
>> linux-next-20101110/kernel/rcutiny_plugin.h:413: error: 'struct rcu_preempt_ctrlblk' has no member named 'n_normal_balk_blkd_tasks'
>
> Hello, Randy,
>
> Good catch! Could you please try the following patch?
(you tested this build, didn't you?)
> Thanx, Paul
Yes, this builds. Thanks.
Acked-by: Randy Dunlap <randy.dunlap@xxxxxxxxxx>
> ------------------------------------------------------------------------
>
> diff --git a/kernel/rcutiny_plugin.h b/kernel/rcutiny_plugin.h
> index 297aa35..8cd197c 100644
> --- a/kernel/rcutiny_plugin.h
> +++ b/kernel/rcutiny_plugin.h
> @@ -297,9 +297,17 @@ static int rcu_boost(void)
> * the current grace period, and, if so, tell the rcu_kthread_task to
> * start boosting them. If there is an expedited boost in progress,
> * we wait for it to complete.
> + *
> + * If there are no blocked readers blocking the current grace period,
> + * return 0 to let the caller know, otherwise return 1. Note that this
> + * return value is independent of whether or not boosting was done.
> */
> -static void rcu_initiate_boost(void)
> +static int rcu_initiate_boost(void)
> {
> + if (!rcu_preempt_blocked_readers_cgp()) {
> + RCU_TRACE(rcu_preempt_ctrlblk.n_normal_balk_blkd_tasks++);
> + return 0;
> + }
> if (rcu_preempt_ctrlblk.gp_tasks != NULL &&
> rcu_preempt_ctrlblk.boost_tasks == NULL &&
> rcu_preempt_ctrlblk.boosted_this_gp == 0 &&
> @@ -309,6 +317,7 @@ static void rcu_initiate_boost(void)
> RCU_TRACE(rcu_preempt_ctrlblk.n_normal_boosts++);
> } else
> RCU_TRACE(rcu_initiate_boost_trace());
> + return 1;
> }
>
> /*
> @@ -353,10 +362,13 @@ static int rcu_boost(void)
> }
>
> /*
> - * If there is no RCU priority boosting, we don't initiate boosting.
> + * If there is no RCU priority boosting, we don't initiate boosting,
> + * but we do indicate whether there are blocked readers blocking the
> + * current grace period.
> */
> -static void rcu_initiate_boost(void)
> +static int rcu_initiate_boost(void)
> {
> + return rcu_preempt_blocked_readers_cgp();
> }
>
> /*
> @@ -405,12 +417,12 @@ static void rcu_preempt_cpu_qs(void)
> /* If there is no GP then there is nothing more to do. */
> if (!rcu_preempt_gp_in_progress())
> return;
> - /* If there are blocked readers, go check up on boosting. */
> - if (rcu_preempt_blocked_readers_cgp()) {
> - rcu_initiate_boost();
> + /*
> + * Check up on boosting. If there are no readers blocking the
> + * current grace period, leave.
> + */
> + if (rcu_initiate_boost())
> return;
> - } else
> - RCU_TRACE(rcu_preempt_ctrlblk.n_normal_balk_blkd_tasks++);
>
> /* Advance callbacks. */
> rcu_preempt_ctrlblk.completed = rcu_preempt_ctrlblk.gpnum;
--
~Randy
*** Remember to use Documentation/SubmitChecklist when testing your code ***
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