[PATCH v6 30/34] drm/i915: Add scheduling priority to per-context parameters

John.C.Harrison
2016-04-20T17:14:33Z

From: Dave Gordon <david.s.gordon@intel.com>

Added an interface for user land applications/libraries/services to
set their GPU scheduler priority. This extends the existing context
parameter IOCTL interface to add a scheduler priority parameter. The
range is +/-1023 with +ve numbers meaning higher priority. Only
system processes may set a higher priority than the default (zero),
normal applications may only lower theirs.

v2: New patch in series.

v6: Updated to use 'to_i915()' instead of dev_private.
[review feedback from Joonas Lahtinen]

For: VIZ-1587
Signed-off-by: Dave Gordon <David.S.Gordon@Intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
---
drivers/gpu/drm/i915/i915_drv.h | 14 ++++++++++++++
drivers/gpu/drm/i915/i915_gem_context.c | 24 ++++++++++++++++++++++++
drivers/gpu/drm/i915/i915_gem_execbuffer.c | 3 +++
include/uapi/drm/i915_drm.h | 1 +
4 files changed, 42 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 25b8fd6..4d5d059 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -815,6 +815,19 @@ struct i915_ctx_hang_stats {
bool banned;
};

+/*
+ * User-settable GFX scheduler priorities are on a scale of -1023 (I don't
+ * care about running) to +1023 (I'm the most important thing in existence)
+ * with zero being the default. Any process may decrease its scheduling
+ * priority, but only a sufficiently privileged process may increase it
+ * beyond zero.
+ */
+
+struct i915_ctx_sched_info {
+ /* Scheduling priority */
+ int32_t priority;
+};
+
struct i915_fence_timeline {
char name[32];
unsigned fence_context;
@@ -855,6 +868,7 @@ struct intel_context {
int flags;
struct drm_i915_file_private *file_priv;
struct i915_ctx_hang_stats hang_stats;
+ struct i915_ctx_sched_info sched_info;
struct i915_hw_ppgtt *ppgtt;

/* Legacy ring buffer submission */
diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
index 6b30de9..6330b39 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -961,6 +961,9 @@ int i915_gem_context_getparam_ioctl(struct drm_device *dev, void *data,
else
args->value = to_i915(dev)->ggtt.base.total;
break;
+ case I915_CONTEXT_PARAM_PRIORITY:
+ args->value = (__u64) ctx->sched_info.priority;
+ break;
default:
ret = -EINVAL;
break;
@@ -998,6 +1001,7 @@ int i915_gem_context_setparam_ioctl(struct drm_device *dev, void *data,
else
ctx->hang_stats.ban_period_seconds = args->value;
break;
+
case I915_CONTEXT_PARAM_NO_ZEROMAP:
if (args->size) {
ret = -EINVAL;
@@ -1006,6 +1010,26 @@ 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_PRIORITY:
+ {
+ int32_t priority = (int32_t) args->value;
+ struct drm_i915_private *dev_priv = to_i915(dev);
+ struct i915_scheduler *scheduler = dev_priv->scheduler;
+
+ if (args->size)
+ ret = -EINVAL;
+ else if ((priority > scheduler->priority_level_max) ||
+ (priority < scheduler->priority_level_min))
+ ret = -EINVAL;
+ else if ((priority > 0) &&
+ !capable(CAP_SYS_ADMIN))
+ ret = -EPERM;
+ else
+ ctx->sched_info.priority = priority;
+ break;
+ }
+
default:
ret = -EINVAL;
break;
diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
index 823283d..fc663fa 100644
--- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
@@ -1719,6 +1719,9 @@ i915_gem_do_execbuffer(struct drm_device *dev, void *data,
params->batch_obj = batch_obj;
params->request = req;

+ /* Start with the context's priority level */
+ qe.priority = ctx->sched_info.priority;
+
/*
* Save away the list of objects used by this batch buffer for the
* purpose of tracking inter-buffer dependencies.
diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
index a5524cc..0e87551 100644
--- a/include/uapi/drm/i915_drm.h
+++ b/include/uapi/drm/i915_drm.h
@@ -1167,6 +1167,7 @@ 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_PRIORITY 0x4
__u64 value;
};