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Message-ID: <484d846f-8fbb-ccd2-d66a-a6b48d4a1df4@linux.alibaba.com>
Date: Wed, 16 Oct 2019 23:26:23 +0800
From: Lai Jiangshan <laijs@...ux.alibaba.com>
To: paulmck@...nel.org, 20191015102402.1978-1-laijs@...ux.alibaba.com
Cc: linux-kernel@...r.kernel.org,
Lai Jiangshan <jiangshanlai@...il.com>,
Josh Triplett <josh@...htriplett.org>,
Steven Rostedt <rostedt@...dmis.org>,
Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
Joel Fernandes <joel@...lfernandes.org>, rcu@...r.kernel.org
Subject: Re: [PATCH 6/7] rcu: rename some CONFIG_PREEMPTION to
CONFIG_PREEMPT_RCU
On 2019/10/16 11:54 上午, Paul E. McKenney wrote:
> On Tue, Oct 15, 2019 at 10:28:48AM +0000, Lai Jiangshan wrote:
>> CONFIG_PREEMPTION and CONFIG_PREEMPT_RCU are always identical,
>> but some code depends on CONFIG_PREEMPTION to access to
>> rcu_preempt functionalitis. This patch changes CONFIG_PREEMPTION
>> to CONFIG_PREEMPT_RCU in these cases.
>>
>> Signed-off-by: Lai Jiangshan <jiangshanlai@...il.com>
>> Signed-off-by: Lai Jiangshan <laijs@...ux.alibaba.com>
>
> I believe that this does not cause problems with Sebastian's patch
> "[PATCH 27/34] rcu: Use CONFIG_PREEMPTION where appropriate", but could
> you please check?
I don't know for which commit the patch "[PATCH 27/34] rcu: Use
CONFIG_PREEMPTION where appropriate" should be applied against
after several tries. But I don't think there will be any conflicts
which this patch by "eye" applying.
Thanks,
Lai
>
> Thanx, Paul
>
>> ---
>> kernel/rcu/tree.c | 4 ++--
>> kernel/rcu/tree_stall.h | 6 +++---
>> 2 files changed, 5 insertions(+), 5 deletions(-)
>>
>> diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
>> index 7db5ea06a9ed..81eb64fcf5ab 100644
>> --- a/kernel/rcu/tree.c
>> +++ b/kernel/rcu/tree.c
>> @@ -1926,7 +1926,7 @@ rcu_report_unblock_qs_rnp(struct rcu_node *rnp, unsigned long flags)
>> struct rcu_node *rnp_p;
>>
>> raw_lockdep_assert_held_rcu_node(rnp);
>> - if (WARN_ON_ONCE(!IS_ENABLED(CONFIG_PREEMPTION)) ||
>> + if (WARN_ON_ONCE(!IS_ENABLED(CONFIG_PREEMPT_RCU)) ||
>> WARN_ON_ONCE(rcu_preempt_blocked_readers_cgp(rnp)) ||
>> rnp->qsmask != 0) {
>> raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
>> @@ -2294,7 +2294,7 @@ static void force_qs_rnp(int (*f)(struct rcu_data *rdp))
>> mask = 0;
>> raw_spin_lock_irqsave_rcu_node(rnp, flags);
>> if (rnp->qsmask == 0) {
>> - if (!IS_ENABLED(CONFIG_PREEMPTION) ||
>> + if (!IS_ENABLED(CONFIG_PREEMPT_RCU) ||
>> rcu_preempt_blocked_readers_cgp(rnp)) {
>> /*
>> * No point in scanning bits because they
>> diff --git a/kernel/rcu/tree_stall.h b/kernel/rcu/tree_stall.h
>> index 0b75426ebb3e..55f9b84790d3 100644
>> --- a/kernel/rcu/tree_stall.h
>> +++ b/kernel/rcu/tree_stall.h
>> @@ -163,7 +163,7 @@ static void rcu_iw_handler(struct irq_work *iwp)
>> //
>> // Printing RCU CPU stall warnings
>>
>> -#ifdef CONFIG_PREEMPTION
>> +#ifdef CONFIG_PREEMPT_RCU
>>
>> /*
>> * Dump detailed information for all tasks blocking the current RCU
>> @@ -215,7 +215,7 @@ static int rcu_print_task_stall(struct rcu_node *rnp)
>> return ndetected;
>> }
>>
>> -#else /* #ifdef CONFIG_PREEMPTION */
>> +#else /* #ifdef CONFIG_PREEMPT_RCU */
>>
>> /*
>> * Because preemptible RCU does not exist, we never have to check for
>> @@ -233,7 +233,7 @@ static int rcu_print_task_stall(struct rcu_node *rnp)
>> {
>> return 0;
>> }
>> -#endif /* #else #ifdef CONFIG_PREEMPTION */
>> +#endif /* #else #ifdef CONFIG_PREEMPT_RCU */
>>
>> /*
>> * Dump stacks of all tasks running on stalled CPUs. First try using
>> --
>> 2.20.1
>>
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