The next use for the i915 get/set per-context parameters ioctl,
ahead of the introduction of the forthcoming GPU scheduler.
Signed-off-by: Dave Gordon <david.s.gordon@xxxxxxxxx>
---
drivers/gpu/drm/i915/i915_drv.h | 28 ++++++++++++++++++++++++++++
drivers/gpu/drm/i915/i915_gem_context.c | 17 +++++++++++++++++
include/uapi/drm/i915_drm.h | 1 +
3 files changed, 46 insertions(+)
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 279e258..104b711 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -850,6 +850,33 @@ struct i915_ctx_hang_stats {
bool banned;
};
+/*
+ * User-settable GFX scheduler priorities are on a scale of 1 (lowest
+ * priority) to 1023 (highest priority). The special value 0 means
+ * "let the system decide my priority automatically"; this is the
+ * default if the user process does not explicitly request a different
+ * priority. Any process may decrease its scheduling priority, but
+ * only a sufficiently-privileged process may increase it. However,
+ * it is always permissible to reset it to "system default", even if
+ * is currently lower than that. Thus, if the system-assigned default
+ * were, say, 256, a process could decrease it to 128, and then to 64.
+ * It could NOT then increase it to 128 again, but COULD request a
+ * priority of 0 -- which would actually reset it to 256, allowing
+ * the process to then request 128 again. (This avoids the issue with
+ * nice(2) priorities, namely that non-super-users can not increase
+ * scheduling priorities of their own processes, even if they were the
+ * ones that decreased the priorities in the first place).
+ */
+
+#define i915_SCHED_PRIORITY_DEFAULT 0
+#define i915_SCHED_PRIORITY_MIN 1
+#define i915_SCHED_PRIORITY_MAX 1023
+
+struct i915_ctx_sched_info {
+ /* Scheduling priority */
+ unsigned long priority;
+};
+
/* This must match up with the value previously used for execbuf2.rsvd1. */
#define DEFAULT_CONTEXT_HANDLE 0
@@ -881,6 +908,7 @@ 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 74aa0c9..2728a0d 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -901,6 +901,9 @@ int i915_gem_context_getparam_ioctl(struct drm_device *dev, void *data,
case I915_CONTEXT_PARAM_NO_ZEROMAP:
args->value = ctx->flags & CONTEXT_NO_ZEROMAP;
break;
+ case I915_CONTEXT_PARAM_PRIORITY:
+ args->value = ctx->sched_info.priority;
+ break;
default:
ret = -EINVAL;
break;
@@ -938,6 +941,7 @@ 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;
@@ -946,6 +950,19 @@ 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:
+ if (args->size)
+ ret = -EINVAL;
+ else if (args->value > I915_SCHED_PRIORITY_MAX)
+ ret = -EINVAL;
+ else if (args->value > ctx->sched_info.priority &&
+ !capable(CAP_SYS_ADMIN))
+ ret = -EPERM;
+ else
+ ctx->sched_info.priority = args->value;
+ break;
+
default:
ret = -EINVAL;
break;
diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
index fd5aa47..a860263 100644
--- a/include/uapi/drm/i915_drm.h
+++ b/include/uapi/drm/i915_drm.h
@@ -1126,6 +1126,7 @@ struct drm_i915_gem_context_param {
__u64 param;
#define I915_CONTEXT_PARAM_BAN_PERIOD 0x1
#define I915_CONTEXT_PARAM_NO_ZEROMAP 0x2
+#define I915_CONTEXT_PARAM_PRIORITY 0x3
__u64 value;
};
--
1.9.1
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