Am Mo., 17. Dez. 2018 um 16:36 Uhr schrieb Lucas Stach <l.stach@xxxxxxxxxxxxxx>:
>
> The only event function that is called from IRQ context is event_free,
> which is already using atomic bitmap operations, so we can avoid taking
> the event spinlock in this function completely. As other the other
> functions still using the event spinlock are all called from normal
> process context, we can avoid disabling IRQs while holding the spinlock.
>
> Signed-off-by: Lucas Stach <l.stach@xxxxxxxxxxxxxx>
Reviewed-by: Christian Gmeiner <christian.gmeiner@xxxxxxxxx>
> ---
> drivers/gpu/drm/etnaviv/etnaviv_gpu.c | 18 +++++-------------
> 1 file changed, 5 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
> index 8fbe77cae810..293e248e1b29 100644
> --- a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
> +++ b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
> @@ -976,7 +976,6 @@ int etnaviv_gpu_debugfs(struct etnaviv_gpu *gpu, struct seq_file *m)
>
> void etnaviv_gpu_recover_hang(struct etnaviv_gpu *gpu)
> {
> - unsigned long flags;
> unsigned int i = 0;
>
> dev_err(gpu->dev, "recover hung GPU!\n");
> @@ -989,11 +988,11 @@ void etnaviv_gpu_recover_hang(struct etnaviv_gpu *gpu)
> etnaviv_hw_reset(gpu);
>
> /* complete all events, the GPU won't do it after the reset */
> - spin_lock_irqsave(&gpu->event_spinlock, flags);
> + spin_lock(&gpu->event_spinlock);
> for_each_set_bit_from(i, gpu->event_bitmap, ETNA_NR_EVENTS)
> complete(&gpu->event_free);
> bitmap_zero(gpu->event_bitmap, ETNA_NR_EVENTS);
> - spin_unlock_irqrestore(&gpu->event_spinlock, flags);
> + spin_unlock(&gpu->event_spinlock);
>
> etnaviv_gpu_hw_init(gpu);
> gpu->lastctx = NULL;
> @@ -1083,7 +1082,7 @@ static inline bool fence_after(u32 a, u32 b)
> static int event_alloc(struct etnaviv_gpu *gpu, unsigned nr_events,
> unsigned int *events)
> {
> - unsigned long flags, timeout = msecs_to_jiffies(10 * 10000);
> + unsigned long timeout = msecs_to_jiffies(10 * 10000);
> unsigned i, acquired = 0;
>
> for (i = 0; i < nr_events; i++) {
> @@ -1100,7 +1099,7 @@ static int event_alloc(struct etnaviv_gpu *gpu, unsigned nr_events,
> timeout = ret;
> }
>
> - spin_lock_irqsave(&gpu->event_spinlock, flags);
> + spin_lock(&gpu->event_spinlock);
>
> for (i = 0; i < nr_events; i++) {
> int event = find_first_zero_bit(gpu->event_bitmap, ETNA_NR_EVENTS);
> @@ -1110,7 +1109,7 @@ static int event_alloc(struct etnaviv_gpu *gpu, unsigned nr_events,
> set_bit(event, gpu->event_bitmap);
> }
>
> - spin_unlock_irqrestore(&gpu->event_spinlock, flags);
> + spin_unlock(&gpu->event_spinlock);
>
> return 0;
>
> @@ -1123,18 +1122,11 @@ static int event_alloc(struct etnaviv_gpu *gpu, unsigned nr_events,
>
> static void event_free(struct etnaviv_gpu *gpu, unsigned int event)
> {
> - unsigned long flags;
> -
> - spin_lock_irqsave(&gpu->event_spinlock, flags);
> -
> if (!test_bit(event, gpu->event_bitmap)) {
> dev_warn(gpu->dev, "event %u is already marked as free",
> event);
> - spin_unlock_irqrestore(&gpu->event_spinlock, flags);
> } else {
> clear_bit(event, gpu->event_bitmap);
> - spin_unlock_irqrestore(&gpu->event_spinlock, flags);
> -
> complete(&gpu->event_free);
> }
> }
> --
> 2.19.1
>
--
greets
--
Christian Gmeiner, MSc
https://christian-gmeiner.info
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