[Intel-gfx] [PATCH] drm/i915: Allow userspace to request no-error-capture upon GPU hangs
Daniel Vetter
daniel at ffwll.ch
Wed Dec 16 00:54:47 PST 2015
On Fri, Dec 11, 2015 at 10:18:35PM +0000, Chris Wilson wrote:
> igt likes to inject GPU hangs into its command streams. However, as we
> expect these hangs, we don't actually want them recorded in the dmesg
> output or stored in the i915_error_state (usually). To accomodate this
> allow userspace to set a flag on the context that any hang emanating
> from that context will not be recorded. We still do the error capture
> (otherwise how do we find the guilty context and know its intent?) as
> part of the reason for random GPU hang injection is to exercise the race
> conditions between the error capture and normal execution.
>
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Hm, I do like that we exercise the full paths all the time, increasing
chances for fireworks. What's the motivation here? Is there some
substantial speed-up?
-Daniel
> ---
> drivers/gpu/drm/i915/i915_drv.h | 8 ++++++--
> drivers/gpu/drm/i915/i915_gem_context.c | 13 ++++++++++++
> drivers/gpu/drm/i915/i915_gpu_error.c | 36 ++++++++++++++-------------------
> include/uapi/drm/i915_drm.h | 1 +
> 4 files changed, 35 insertions(+), 23 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index b33091c2c39e..c511b3cbf9b2 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -493,6 +493,7 @@ struct drm_i915_error_state {
> struct timeval time;
>
> char error_msg[128];
> + bool simulated;
> int iommu;
> u32 reset_count;
> u32 suspend_count;
> @@ -845,7 +846,9 @@ struct i915_ctx_hang_stats {
> /* This must match up with the value previously used for execbuf2.rsvd1. */
> #define DEFAULT_CONTEXT_HANDLE 0
>
> -#define CONTEXT_NO_ZEROMAP (1<<0)
> +#define CONTEXT_NO_ZEROMAP (1<<0)
> +#define CONTEXT_NO_ERROR_CAPTURE (1<<1)
> +
> /**
> * struct intel_context - as the name implies, represents a context.
> * @ref: reference count.
> @@ -870,11 +873,12 @@ struct intel_context {
> int user_handle;
> uint8_t remap_slice;
> struct drm_i915_private *i915;
> - int flags;
> struct drm_i915_file_private *file_priv;
> struct i915_ctx_hang_stats hang_stats;
> struct i915_hw_ppgtt *ppgtt;
>
> + unsigned flags;
> +
> /* Legacy ring buffer submission */
> struct {
> struct drm_i915_gem_object *rcs_state;
> diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
> index 900ffd044db8..d9998ab9d94d 100644
> --- a/drivers/gpu/drm/i915/i915_gem_context.c
> +++ b/drivers/gpu/drm/i915/i915_gem_context.c
> @@ -938,6 +938,9 @@ int i915_gem_context_getparam_ioctl(struct drm_device *dev, void *data,
> else
> args->value = to_i915(dev)->gtt.base.total;
> break;
> + case I915_CONTEXT_PARAM_NO_ERROR_CAPTURE:
> + args->value = !!(ctx->flags & CONTEXT_NO_ERROR_CAPTURE);
> + break;
> default:
> ret = -EINVAL;
> break;
> @@ -983,6 +986,16 @@ int i915_gem_context_setparam_ioctl(struct drm_device *dev, void *data,
> ctx->flags |= args->value ? CONTEXT_NO_ZEROMAP : 0;
> }
> break;
> + case I915_CONTEXT_PARAM_NO_ERROR_CAPTURE:
> + if (args->size) {
> + ret = -EINVAL;
> + } else {
> + if (args->value)
> + ctx->flags |= CONTEXT_NO_ERROR_CAPTURE;
> + else
> + ctx->flags &= ~CONTEXT_NO_ERROR_CAPTURE;
> + }
> + break;
> default:
> ret = -EINVAL;
> break;
> diff --git a/drivers/gpu/drm/i915/i915_gpu_error.c b/drivers/gpu/drm/i915/i915_gpu_error.c
> index 3e137fc701cf..cb0d6f347d42 100644
> --- a/drivers/gpu/drm/i915/i915_gpu_error.c
> +++ b/drivers/gpu/drm/i915/i915_gpu_error.c
> @@ -995,7 +995,7 @@ static void i915_gem_record_rings(struct drm_device *dev,
>
> for (i = 0; i < I915_NUM_RINGS; i++) {
> struct intel_engine_cs *ring = &dev_priv->ring[i];
> - struct intel_ringbuffer *rbuf;
> + struct intel_ringbuffer *rbuf = NULL;
>
> error->ring[i].pid = -1;
>
> @@ -1039,23 +1039,15 @@ static void i915_gem_record_rings(struct drm_device *dev,
> }
> rcu_read_unlock();
> }
> - }
>
> - if (i915.enable_execlists) {
> - /* TODO: This is only a small fix to keep basic error
> - * capture working, but we need to add more information
> - * for it to be useful (e.g. dump the context being
> - * executed).
> - */
> - if (request)
> - rbuf = request->ctx->engine[ring->id].ringbuf;
> - else
> - rbuf = ring->default_context->engine[ring->id].ringbuf;
> - } else
> - rbuf = ring->buffer;
> + error->simulated |= request->ctx->flags & CONTEXT_NO_ERROR_CAPTURE;
> + rbuf = request->ringbuf;
> + }
>
> - error->ring[i].cpu_ring_head = rbuf->head;
> - error->ring[i].cpu_ring_tail = rbuf->tail;
> + if (rbuf) {
> + error->ring[i].cpu_ring_head = rbuf->head;
> + error->ring[i].cpu_ring_tail = rbuf->tail;
> + }
>
> error->ring[i].ringbuffer =
> i915_error_ggtt_object_create(dev_priv, rbuf->obj);
> @@ -1345,12 +1337,14 @@ void i915_capture_error_state(struct drm_device *dev, bool wedged,
> i915_error_capture_msg(dev, error, wedged, error_msg);
> DRM_INFO("%s\n", error->error_msg);
>
> - spin_lock_irqsave(&dev_priv->gpu_error.lock, flags);
> - if (dev_priv->gpu_error.first_error == NULL) {
> - dev_priv->gpu_error.first_error = error;
> - error = NULL;
> + if (!error->simulated) {
> + spin_lock_irqsave(&dev_priv->gpu_error.lock, flags);
> + if (dev_priv->gpu_error.first_error == NULL) {
> + dev_priv->gpu_error.first_error = error;
> + error = NULL;
> + }
> + spin_unlock_irqrestore(&dev_priv->gpu_error.lock, flags);
> }
> - spin_unlock_irqrestore(&dev_priv->gpu_error.lock, flags);
>
> if (error) {
> i915_error_state_free(&error->ref);
> diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
> index acf21026c78a..7fee4416dcc7 100644
> --- a/include/uapi/drm/i915_drm.h
> +++ b/include/uapi/drm/i915_drm.h
> @@ -1140,6 +1140,7 @@ struct drm_i915_gem_context_param {
> #define I915_CONTEXT_PARAM_BAN_PERIOD 0x1
> #define I915_CONTEXT_PARAM_NO_ZEROMAP 0x2
> #define I915_CONTEXT_PARAM_GTT_SIZE 0x3
> +#define I915_CONTEXT_PARAM_NO_ERROR_CAPTURE 0x4
> __u64 value;
> };
>
> --
> 2.6.3
>
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> Intel-gfx at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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