From: Neeraj Upadhyay <neeraju@codeaurora.org>
To: paulmck@kernel.org
Cc: josh@joshtriplett.org, rostedt@goodmis.org,
mathieu.desnoyers@efficios.com, jiangshanlai@gmail.com,
joel@joelfernandes.org, rcu@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] rcu/tree: Force quiescent state on callback overload
Date: Mon, 22 Jun 2020 01:30:31 +0530 [thread overview]
Message-ID: <94686c2e-b589-2598-e658-42f13cec1216@codeaurora.org> (raw)
In-Reply-To: <20200621195052.GF9247@paulmck-ThinkPad-P72>
Hi Paul,
On 6/22/2020 1:20 AM, Paul E. McKenney wrote:
> On Mon, Jun 22, 2020 at 12:07:27AM +0530, Neeraj Upadhyay wrote:
>> On callback overload, we want to force quiescent state immediately,
>> for the first and second fqs. Enforce the same, by including
>> RCU_GP_FLAG_OVLD flag, in fqsstart check.
>>
>> Signed-off-by: Neeraj Upadhyay <neeraju@codeaurora.org>
>
> Good catch!
>
> But what did you do to verify that this change does the right thing?
>
> Thanx, Paul
>
I haven't done a runtime verification of this code path; I posted this,
based on review of this code.
Thanks
Neeraj
>> ---
>> kernel/rcu/tree.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
>> index d0988a1..6226bfb 100644
>> --- a/kernel/rcu/tree.c
>> +++ b/kernel/rcu/tree.c
>> @@ -1865,7 +1865,7 @@ static void rcu_gp_fqs_loop(void)
>> break;
>> /* If time for quiescent-state forcing, do it. */
>> if (!time_after(rcu_state.jiffies_force_qs, jiffies) ||
>> - (gf & RCU_GP_FLAG_FQS)) {
>> + (gf & (RCU_GP_FLAG_FQS | RCU_GP_FLAG_OVLD))) {
>> trace_rcu_grace_period(rcu_state.name, rcu_state.gp_seq,
>> TPS("fqsstart"));
>> rcu_gp_fqs(first_gp_fqs);
>> --
>> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
>> a Linux Foundation Collaborative Project
>>
--
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a
member of the Code Aurora Forum, hosted by The Linux Foundation
next prev parent reply other threads:[~2020-06-21 20:00 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-21 18:37 [PATCH] rcu/tree: Force quiescent state on callback overload Neeraj Upadhyay
2020-06-21 19:50 ` Paul E. McKenney
2020-06-21 20:00 ` Neeraj Upadhyay [this message]
2020-06-22 3:13 ` Paul E. McKenney
2020-06-22 3:46 ` Neeraj Upadhyay
2020-06-22 22:53 ` Paul E. McKenney
2020-06-23 6:19 ` Neeraj Upadhyay
2020-06-23 15:42 ` Joel Fernandes
2020-06-23 16:29 ` Paul E. McKenney
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