From: Doug Anderson <dianders@chromium.org>
To: Sumit Garg <sumit.garg@linaro.org>
Cc: Daniel Thompson <daniel.thompson@linaro.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
linux-serial@vger.kernel.org,
kgdb-bugreport@lists.sourceforge.net,
Jiri Slaby <jslaby@suse.com>,
Russell King - ARM Linux <linux@armlinux.org.uk>,
Jason Wessel <jason.wessel@windriver.com>,
LKML <linux-kernel@vger.kernel.org>,
Linux ARM <linux-arm-kernel@lists.infradead.org>
Subject: Re: [RFC 2/5] serial: core: Add framework to allow NMI aware serial drivers
Date: Mon, 17 Aug 2020 06:57:22 -0700 [thread overview]
Message-ID: <CAD=FV=WiZi18zBwx9J0sKLdCqMCvxuQ=U0m21yNqhtaBfZEqzA@mail.gmail.com> (raw)
In-Reply-To: <CAFA6WYNAdELYCoOVQokgLNKhOYF9QK85UidgvyFfo4wsSNwKXw@mail.gmail.com>
Hi,
On Mon, Aug 17, 2020 at 5:27 AM Sumit Garg <sumit.garg@linaro.org> wrote:
>
> Thanks for your suggestion, irq_work_schedule() looked even better
> without any overhead, see below:
>
> diff --git a/include/linux/irq_work.h b/include/linux/irq_work.h
> index 3082378..1eade89 100644
> --- a/include/linux/irq_work.h
> +++ b/include/linux/irq_work.h
> @@ -3,6 +3,7 @@
> #define _LINUX_IRQ_WORK_H
>
> #include <linux/smp_types.h>
> +#include <linux/workqueue.h>
>
> /*
> * An entry can be in one of four states:
> @@ -24,6 +25,11 @@ struct irq_work {
> void (*func)(struct irq_work *);
> };
>
> +struct irq_work_schedule {
> + struct irq_work work;
> + struct work_struct *sched_work;
> +};
> +
> static inline
> void init_irq_work(struct irq_work *work, void (*func)(struct irq_work *))
> {
> {
> @@ -39,6 +45,7 @@ void init_irq_work(struct irq_work *work, void
> (*func)(struct irq_work *))
>
> bool irq_work_queue(struct irq_work *work);
> bool irq_work_queue_on(struct irq_work *work, int cpu);
> +bool irq_work_schedule(struct work_struct *sched_work);
>
> void irq_work_tick(void);
> void irq_work_sync(struct irq_work *work);
> diff --git a/kernel/irq_work.c b/kernel/irq_work.c
> index eca8396..3880316 100644
> --- a/kernel/irq_work.c
> +++ b/kernel/irq_work.c
> @@ -24,6 +24,8 @@
> static DEFINE_PER_CPU(struct llist_head, raised_list);
> static DEFINE_PER_CPU(struct llist_head, lazy_list);
>
> +static struct irq_work_schedule irq_work_sched;
> +
> /*
> * Claim the entry so that no one else will poke at it.
> */
> @@ -79,6 +81,25 @@ bool irq_work_queue(struct irq_work *work)
> }
> EXPORT_SYMBOL_GPL(irq_work_queue);
>
> +static void irq_work_schedule_fn(struct irq_work *work)
> +{
> + struct irq_work_schedule *irq_work_sched =
> + container_of(work, struct irq_work_schedule, work);
> +
> + if (irq_work_sched->sched_work)
> + schedule_work(irq_work_sched->sched_work);
> +}
> +
> +/* Schedule work via irq work queue */
> +bool irq_work_schedule(struct work_struct *sched_work)
> +{
> + init_irq_work(&irq_work_sched.work, irq_work_schedule_fn);
> + irq_work_sched.sched_work = sched_work;
> +
> + return irq_work_queue(&irq_work_sched.work);
> +}
> +EXPORT_SYMBOL_GPL(irq_work_schedule);
Wait, howzat work? There's a single global variable that you stash
the "sched_work" into with no locking? What if two people schedule
work at the same time?
-Doug
next prev parent reply other threads:[~2020-08-17 13:57 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-21 12:10 [RFC 0/5] Introduce NMI aware serial drivers Sumit Garg
2020-07-21 12:10 ` [RFC 1/5] tty/sysrq: Make sysrq handler NMI aware Sumit Garg
2020-08-12 23:59 ` Doug Anderson
2020-08-14 7:24 ` Sumit Garg
2020-08-14 14:34 ` peterz
2020-08-14 14:57 ` Doug Anderson
2020-08-17 14:08 ` Sumit Garg
2020-08-17 17:19 ` Doug Anderson
2020-08-18 13:30 ` Sumit Garg
2020-07-21 12:10 ` [RFC 2/5] serial: core: Add framework to allow NMI aware serial drivers Sumit Garg
2020-08-12 23:59 ` Doug Anderson
2020-08-13 14:19 ` Sumit Garg
2020-08-13 14:37 ` Doug Anderson
2020-08-14 11:17 ` Sumit Garg
2020-08-14 14:13 ` Daniel Thompson
2020-08-17 12:27 ` Sumit Garg
2020-08-17 13:57 ` Doug Anderson [this message]
2020-08-17 14:23 ` Sumit Garg
2020-08-17 14:32 ` Daniel Thompson
2020-08-18 13:18 ` Sumit Garg
2020-08-17 14:28 ` Daniel Thompson
2020-08-18 13:06 ` Sumit Garg
2020-08-14 14:43 ` Doug Anderson
2020-08-17 12:29 ` Sumit Garg
2020-07-21 12:10 ` [RFC 3/5] serial: amba-pl011: Re-order APIs definition Sumit Garg
2020-07-21 12:10 ` [RFC 4/5] serial: amba-pl011: Enable NMI aware uart port Sumit Garg
2020-08-12 23:59 ` Doug Anderson
2020-08-13 10:34 ` Sumit Garg
2020-07-21 12:10 ` [RFC 5/5] serial: Remove KGDB NMI serial driver Sumit Garg
2020-08-11 13:50 ` [RFC 0/5] Introduce NMI aware serial drivers Sumit Garg
2020-08-11 13:58 ` Greg Kroah-Hartman
2020-08-11 14:29 ` Sumit Garg
2020-08-11 14:58 ` Greg Kroah-Hartman
2020-08-11 17:15 ` Doug Anderson
2020-08-12 14:52 ` Sumit Garg
2020-08-12 15:27 ` Doug Anderson
2020-08-13 0:08 ` Doug Anderson
2020-08-13 9:25 ` Sumit Garg
2020-08-13 10:17 ` Daniel Thompson
2020-08-14 12:06 ` Sumit Garg
2020-08-14 14:18 ` Daniel Thompson
2020-08-17 5:12 ` Sumit Garg
2020-08-17 9:28 ` Daniel Thompson
2020-08-17 14:12 ` Sumit Garg
2020-08-13 15:26 ` Doug Anderson
2020-08-14 12:50 ` Sumit Garg
2020-08-12 5:48 ` Sumit Garg
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