From: Frederic Weisbecker <frederic@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: mingo@kernel.org, linux-kernel@vger.kernel.org, will@kernel.org,
paulmck@kernel.org, hch@lst.de, axboe@kernel.dk,
chris@chris-wilson.co.uk, davem@davemloft.net, kuba@kernel.org,
fweisbec@gmail.com, oleg@redhat.com, vincent.guittot@linaro.org
Subject: Re: [PATCH v3 5/6] irq_work: Provide irq_work_queue_remote()
Date: Wed, 28 Oct 2020 14:40:46 +0100 [thread overview]
Message-ID: <20201028134046.GE229044@lothringen> (raw)
In-Reply-To: <20201028111221.526249871@infradead.org>
On Wed, Oct 28, 2020 at 12:07:12PM +0100, Peter Zijlstra wrote:
> While the traditional irq_work relies on the ability to self-IPI, it
> makes sense to provide an unconditional irq_work_queue_remote()
> interface.
We may need a reason as well here.
> --- a/kernel/rcu/tree.c
> +++ b/kernel/rcu/tree.c
> @@ -1308,13 +1308,14 @@ static int rcu_implicit_dynticks_qs(stru
> resched_cpu(rdp->cpu);
> WRITE_ONCE(rdp->last_fqs_resched, jiffies);
> }
> - if (IS_ENABLED(CONFIG_IRQ_WORK) &&
> - !rdp->rcu_iw_pending && rdp->rcu_iw_gp_seq != rnp->gp_seq &&
> +#ifdef CONFIG_IRQ_WORK
> + if (!rdp->rcu_iw_pending && rdp->rcu_iw_gp_seq != rnp->gp_seq &&
If it's unconditional on SMP, I expect it to be unconditional on rcutree.
Also this chunk seems unrelated to this patch.
> (rnp->ffmask & rdp->grpmask)) {
> rdp->rcu_iw_pending = true;
> rdp->rcu_iw_gp_seq = rnp->gp_seq;
> irq_work_queue_on(&rdp->rcu_iw, rdp->cpu);
> }
> +#endif
> }
>
> return 0;
>
>
next prev parent reply other threads:[~2020-10-28 22:18 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-28 11:07 [PATCH v3 0/6] smp: irq_work / smp_call_function rework Peter Zijlstra
2020-10-28 11:07 ` [PATCH v3 1/6] irq_work: Cleanup Peter Zijlstra
2020-10-28 13:01 ` Frederic Weisbecker
2020-10-28 11:07 ` [PATCH v3 2/6] smp: Cleanup smp_call_function*() Peter Zijlstra
2020-10-28 13:25 ` Frederic Weisbecker
2020-10-28 11:07 ` [PATCH v3 3/6] irq_work: Optimize irq_work_single() Peter Zijlstra
2020-10-28 12:06 ` Frederic Weisbecker
2020-10-28 11:07 ` [PATCH v3 4/6] irq_work: Unconditionally build on SMP Peter Zijlstra
2020-10-28 13:34 ` Frederic Weisbecker
2020-10-28 14:52 ` Peter Zijlstra
2020-10-28 11:07 ` [PATCH v3 5/6] irq_work: Provide irq_work_queue_remote() Peter Zijlstra
2020-10-28 13:40 ` Frederic Weisbecker [this message]
2020-10-28 14:38 ` Peter Zijlstra
2020-10-28 14:53 ` Peter Zijlstra
2020-10-28 14:56 ` Frederic Weisbecker
2020-10-28 11:07 ` [RFC][PATCH v3 6/6] rcu/tree: Use irq_work_queue_remote() Peter Zijlstra
2020-10-28 14:54 ` Peter Zijlstra
2020-10-28 20:02 ` Peter Zijlstra
2020-10-28 20:15 ` Paul E. McKenney
2020-10-29 9:10 ` Peter Zijlstra
2020-10-29 16:04 ` Paul E. McKenney
2020-10-29 16:14 ` Peter Zijlstra
2020-10-29 9:15 ` Peter Zijlstra
2020-10-29 16:06 ` Paul E. McKenney
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