On 21/06/2021 17:09, Steven Price wrote:
> On 21/06/2021 15:02, Boris Brezillon wrote:
>> This should avoid uneccessary interrupt-context switches when the GPU
>> is passed a lot of short jobs.
>
> LGTM:
>
> Reviewed-by: Steven Price <steven.price@xxxxxxx>
Well actually... see below.
>>
>> v2:
>> * New patch
>>
>> Signed-off-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx>
>> ---
>> drivers/gpu/drm/panfrost/panfrost_job.c | 54 +++++++++++++++++--------
>> 1 file changed, 38 insertions(+), 16 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c b/drivers/gpu/drm/panfrost/panfrost_job.c
>> index cf6abe0fdf47..1b5c636794a1 100644
>> --- a/drivers/gpu/drm/panfrost/panfrost_job.c
>> +++ b/drivers/gpu/drm/panfrost/panfrost_job.c
>> @@ -473,19 +473,12 @@ static const struct drm_sched_backend_ops panfrost_sched_ops = {
>> .free_job = panfrost_job_free
>> };
>>
>> -static irqreturn_t panfrost_job_irq_handler(int irq, void *data)
>> +static void panfrost_job_handle_irq(struct panfrost_device *pfdev, u32 status)
>> {
>> - struct panfrost_device *pfdev = data;
>> - u32 status = job_read(pfdev, JOB_INT_STAT);
>> int j;
>>
>> dev_dbg(pfdev->dev, "jobslot irq status=%x\n", status);
>>
>> - if (!status)
>> - return IRQ_NONE;
>> -
>> - pm_runtime_mark_last_busy(pfdev->dev);
>> -
>> for (j = 0; status; j++) {
>> u32 mask = MK_JS_MASK(j);
>>
>> @@ -558,16 +551,43 @@ static irqreturn_t panfrost_job_irq_handler(int irq, void *data)
Missing context:
> if (status & JOB_INT_MASK_DONE(j)) {
> struct panfrost_job *job;
>
> spin_lock(&pfdev->js->job_lock);
> job = pfdev->jobs[j];
> /* Only NULL if job timeout occurred */
> if (job) {
> pfdev->jobs[j] = NULL;
>
> panfrost_mmu_as_put(pfdev, job->file_priv->mmu);
> panfrost_devfreq_record_idle(&pfdev->pfdevfreq);
>
> dma_fence_signal_locked(job->done_fence);
> pm_runtime_put_autosuspend(pfdev->dev);
> }
> spin_unlock(&pfdev->js->job_lock);
> }
^^^ Here we're still taking job_lock which is now held by
panfrost_job_irq_handler_thread().
This is removed by the following patch, but it breaks bisection.
Steve
>>
>> status &= ~mask;
>> }
>> +}
>>
>> +static irqreturn_t panfrost_job_irq_handler_thread(int irq, void *data)
>> +{
>> + struct panfrost_device *pfdev = data;
>> + u32 status = job_read(pfdev, JOB_INT_RAWSTAT);
>> +
>> + while (status) {
>> + pm_runtime_mark_last_busy(pfdev->dev);
>> +
>> + spin_lock(&pfdev->js->job_lock);
>> + panfrost_job_handle_irq(pfdev, status);
>> + spin_unlock(&pfdev->js->job_lock);
>> + status = job_read(pfdev, JOB_INT_RAWSTAT);
>> + }
>> +
>> + job_write(pfdev, JOB_INT_MASK, ~0);
>> return IRQ_HANDLED;
>> }
>>
>> +static irqreturn_t panfrost_job_irq_handler(int irq, void *data)
>> +{
>> + struct panfrost_device *pfdev = data;
>> + u32 status = job_read(pfdev, JOB_INT_STAT);
>> +
>> + if (!status)
>> + return IRQ_NONE;
>> +
>> + job_write(pfdev, JOB_INT_MASK, 0);
>> + return IRQ_WAKE_THREAD;
>> +}
>> +
>> static void panfrost_reset(struct work_struct *work)
>> {
>> struct panfrost_device *pfdev = container_of(work,
>> struct panfrost_device,
>> reset.work);
>> - unsigned long flags;
>> unsigned int i;
>>
>> for (i = 0; i < NUM_JOB_SLOTS; i++) {
>> @@ -595,7 +615,7 @@ static void panfrost_reset(struct work_struct *work)
>> /* All timers have been stopped, we can safely reset the pending state. */
>> atomic_set(&pfdev->reset.pending, 0);
>>
>> - spin_lock_irqsave(&pfdev->js->job_lock, flags);
>> + spin_lock(&pfdev->js->job_lock);
>> for (i = 0; i < NUM_JOB_SLOTS; i++) {
>> if (pfdev->jobs[i]) {
>> pm_runtime_put_noidle(pfdev->dev);
>> @@ -603,7 +623,7 @@ static void panfrost_reset(struct work_struct *work)
>> pfdev->jobs[i] = NULL;
>> }
>> }
>> - spin_unlock_irqrestore(&pfdev->js->job_lock, flags);
>> + spin_unlock(&pfdev->js->job_lock);
>>
>> panfrost_device_reset(pfdev);
>>
>> @@ -628,8 +648,11 @@ int panfrost_job_init(struct panfrost_device *pfdev)
>> if (irq <= 0)
>> return -ENODEV;
>>
>> - ret = devm_request_irq(pfdev->dev, irq, panfrost_job_irq_handler,
>> - IRQF_SHARED, KBUILD_MODNAME "-job", pfdev);
>> + ret = devm_request_threaded_irq(pfdev->dev, irq,
>> + panfrost_job_irq_handler,
>> + panfrost_job_irq_handler_thread,
>> + IRQF_SHARED, KBUILD_MODNAME "-job",
>> + pfdev);
>> if (ret) {
>> dev_err(pfdev->dev, "failed to request job irq");
>> return ret;
>> @@ -696,14 +719,13 @@ int panfrost_job_open(struct panfrost_file_priv *panfrost_priv)
>> void panfrost_job_close(struct panfrost_file_priv *panfrost_priv)
>> {
>> struct panfrost_device *pfdev = panfrost_priv->pfdev;
>> - unsigned long flags;
>> int i;
>>
>> for (i = 0; i < NUM_JOB_SLOTS; i++)
>> drm_sched_entity_destroy(&panfrost_priv->sched_entity[i]);
>>
>> /* Kill in-flight jobs */
>> - spin_lock_irqsave(&pfdev->js->job_lock, flags);
>> + spin_lock(&pfdev->js->job_lock);
>> for (i = 0; i < NUM_JOB_SLOTS; i++) {
>> struct drm_sched_entity *entity = &panfrost_priv->sched_entity[i];
>> struct panfrost_job *job = pfdev->jobs[i];
>> @@ -713,7 +735,7 @@ void panfrost_job_close(struct panfrost_file_priv *panfrost_priv)
>>
>> job_write(pfdev, JS_COMMAND(i), JS_COMMAND_HARD_STOP);
>> }
>> - spin_unlock_irqrestore(&pfdev->js->job_lock, flags);
>> + spin_unlock(&pfdev->js->job_lock);
>> }
>>
>> int panfrost_job_is_idle(struct panfrost_device *pfdev)
>>
>
