linux-kernel - Re: [PATCH v3 02/12] bus: mhi: core: Move to using high priority workqueue

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Date:   Fri, 30 Oct 2020 19:05:34 +0530
From:   Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
To:     Bhaumik Bhatt <bbhatt@...eaurora.org>
Cc:     linux-arm-msm@...r.kernel.org, hemantk@...eaurora.org,
        jhugo@...eaurora.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 02/12] bus: mhi: core: Move to using high priority
 workqueue

On Thu, Oct 29, 2020 at 09:10:47PM -0700, Bhaumik Bhatt wrote:
> MHI work is currently scheduled on the global/system workqueue and can
> encounter delays on a stressed system. To avoid those unforeseen
> delays which can hamper bootup or shutdown times, use a dedicated high
> priority workqueue instead of the global/system workqueue.
> 
> Signed-off-by: Bhaumik Bhatt <bbhatt@...eaurora.org>

You are not destroying the workqueue in mhi_unregister_controller().
With that fixed,

Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>

Thanks,
Mani

> ---
>  drivers/bus/mhi/core/init.c | 8 ++++++++
>  drivers/bus/mhi/core/pm.c   | 2 +-
>  include/linux/mhi.h         | 2 ++
>  3 files changed, 11 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/bus/mhi/core/init.c b/drivers/bus/mhi/core/init.c
> index 0ffdebd..23b6dd6 100644
> --- a/drivers/bus/mhi/core/init.c
> +++ b/drivers/bus/mhi/core/init.c
> @@ -880,6 +880,13 @@ int mhi_register_controller(struct mhi_controller *mhi_cntrl,
>  	INIT_WORK(&mhi_cntrl->st_worker, mhi_pm_st_worker);
>  	init_waitqueue_head(&mhi_cntrl->state_event);
>  
> +	mhi_cntrl->hiprio_wq = alloc_ordered_workqueue
> +				("mhi_hiprio_wq", WQ_MEM_RECLAIM | WQ_HIGHPRI);
> +	if (!mhi_cntrl->hiprio_wq) {
> +		dev_err(mhi_cntrl->cntrl_dev, "Failed to allocate workqueue\n");
> +		goto error_alloc_cmd;
> +	}
> +
>  	mhi_cmd = mhi_cntrl->mhi_cmd;
>  	for (i = 0; i < NR_OF_CMD_RINGS; i++, mhi_cmd++)
>  		spin_lock_init(&mhi_cmd->lock);
> @@ -969,6 +976,7 @@ int mhi_register_controller(struct mhi_controller *mhi_cntrl,
>  error_alloc_cmd:
>  	vfree(mhi_cntrl->mhi_chan);
>  	kfree(mhi_cntrl->mhi_event);
> +	destroy_workqueue(mhi_cntrl->hiprio_wq);
>  
>  	return ret;
>  }
> diff --git a/drivers/bus/mhi/core/pm.c b/drivers/bus/mhi/core/pm.c
> index 3de7b16..805b6fa74 100644
> --- a/drivers/bus/mhi/core/pm.c
> +++ b/drivers/bus/mhi/core/pm.c
> @@ -597,7 +597,7 @@ int mhi_queue_state_transition(struct mhi_controller *mhi_cntrl,
>  	list_add_tail(&item->node, &mhi_cntrl->transition_list);
>  	spin_unlock_irqrestore(&mhi_cntrl->transition_lock, flags);
>  
> -	schedule_work(&mhi_cntrl->st_worker);
> +	queue_work(mhi_cntrl->hiprio_wq, &mhi_cntrl->st_worker);
>  
>  	return 0;
>  }
> diff --git a/include/linux/mhi.h b/include/linux/mhi.h
> index d4841e5..8961cbc 100644
> --- a/include/linux/mhi.h
> +++ b/include/linux/mhi.h
> @@ -337,6 +337,7 @@ struct mhi_controller_config {
>   * @wlock: Lock for protecting device wakeup
>   * @mhi_link_info: Device bandwidth info
>   * @st_worker: State transition worker
> + * @hiprio_wq: High priority workqueue for MHI work such as state transitions
>   * @state_event: State change event
>   * @status_cb: CB function to notify power states of the device (required)
>   * @wake_get: CB function to assert device wake (optional)
> @@ -419,6 +420,7 @@ struct mhi_controller {
>  	spinlock_t wlock;
>  	struct mhi_link_info mhi_link_info;
>  	struct work_struct st_worker;
> +	struct workqueue_struct *hiprio_wq;
>  	wait_queue_head_t state_event;
>  
>  	void (*status_cb)(struct mhi_controller *mhi_cntrl,
> -- 
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project
>