Re: [PATCH 01/32] arm/omap: use system_wq in mailbox

[Kanigeri, Hari]

Tejun,

On Mon, Jan 3, 2011 at 7:49 AM, Tejun Heo <tj@xxxxxxxxxx> wrote:
> With cmwq, there's no reason to use a separate workqueue for mailbox.
> Use the system_wq instead.  mbox->rxq->work is sync flushed in
> omap_mbox_fini() to make sure it's not running on any cpu, which makes
> sure that no mbox work is running when omap_mbox_exit() is entered.
>
> Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
> Cc: Tony Lindgren <tony@xxxxxxxxxxx>
> Cc: linux-omap@xxxxxxxxxxxxxxx
> ---
> Only compile tested.  Please feel free to take it into the subsystem
> tree or simply ack - I'll route it through the wq tree.

This was changed to dedicated work queue because of performance issues
when there is heavy mailbox traffic between the cores.

Reference:
http://www.mail-archive.com/linux-omap@xxxxxxxxxxxxxxx/msg24240.html


>
> Thanks.
>
>  arch/arm/plat-omap/mailbox.c |   10 ++--------
>  1 files changed, 2 insertions(+), 8 deletions(-)
>
> diff --git a/arch/arm/plat-omap/mailbox.c b/arch/arm/plat-omap/mailbox.c
> index d2fafb8..5bc4d7b 100644
> --- a/arch/arm/plat-omap/mailbox.c
> +++ b/arch/arm/plat-omap/mailbox.c
> @@ -31,7 +31,6 @@
>
>  #include <plat/mailbox.h>
>
> -static struct workqueue_struct *mboxd;
>  static struct omap_mbox **mboxes;
>  static bool rq_full;
>
> @@ -186,7 +185,7 @@ static void __mbox_rx_interrupt(struct omap_mbox *mbox)
>        /* no more messages in the fifo. clear IRQ source. */
>        ack_mbox_irq(mbox, IRQ_RX);
>  nomem:
> -       queue_work(mboxd, &mbox->rxq->work);
> +       schedule_work(&mbox->rxq->work);
>  }
>
>  static irqreturn_t mbox_interrupt(int irq, void *p)
> @@ -291,7 +290,7 @@ static void omap_mbox_fini(struct omap_mbox *mbox)
>  {
>        free_irq(mbox->irq, mbox);
>        tasklet_kill(&mbox->txq->tasklet);
> -       flush_work(&mbox->rxq->work);
> +       flush_work_sync(&mbox->rxq->work);
>        mbox_queue_free(mbox->txq);
>        mbox_queue_free(mbox->rxq);
>
> @@ -385,10 +384,6 @@ static int __init omap_mbox_init(void)
>        if (err)
>                return err;
>
> -       mboxd = create_workqueue("mboxd");
> -       if (!mboxd)
> -               return -ENOMEM;
> -
>        /* kfifo size sanity check: alignment and minimal size */
>        mbox_kfifo_size = ALIGN(mbox_kfifo_size, sizeof(mbox_msg_t));
>        mbox_kfifo_size = max_t(unsigned int, mbox_kfifo_size, sizeof(mbox_msg_t));
> @@ -399,7 +394,6 @@ subsys_initcall(omap_mbox_init);
>
>  static void __exit omap_mbox_exit(void)
>  {
> -       destroy_workqueue(mboxd);
>        class_unregister(&omap_mbox_class);
>  }
>  module_exit(omap_mbox_exit);
> --
> 1.7.1
>
> --
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-- 
Thank you,
Best regards,
Hari Kanigeri
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