There are cases where a system integrator may wish to raise/lower the
priority of GPU workloads being submitted by specific OS process(es),
independently of how the software self-classifies its own priority.
Exposing "priority offset" as an i915-specific cgroup parameter will
enable such system-level configuration.
Normally GPU contexts start with a priority value of 0
(I915_CONTEXT_DEFAULT_PRIORITY) and then may be adjusted up/down from
there via other mechanisms. We'd like to provide a system-level input
to the priority decision that will be taken into consideration, even
when userspace later attempts to set an absolute priority value via
I915_CONTEXT_PARAM_PRIORITY. The priority offset introduced here
provides a base value that will always be added to (or subtracted from)
the software's self-assigned priority value.
This patch makes priority offset a cgroup-specific value; contexts will
be created with a priority offset based on the cgroup membership of the
process creating the context at the time the context is created. Note
that priority offset is assigned at context creation time; migrating a
process to a different cgroup or changing the offset associated with a
cgroup will only affect new context creation and will not alter the
behavior of existing contexts previously created by the process.
Signed-off-by: Matt Roper <matthew.d.roper@xxxxxxxxx>
---
drivers/gpu/drm/i915/i915_cgroup.c | 46 +++++++++++++++++++++++++++++++++
drivers/gpu/drm/i915/i915_drv.h | 7 +++++
drivers/gpu/drm/i915/i915_gem_context.c | 6 +++--
drivers/gpu/drm/i915/i915_gem_context.h | 9 +++++++
include/uapi/drm/i915_drm.h | 1 +
5 files changed, 67 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_cgroup.c b/drivers/gpu/drm/i915/i915_cgroup.c
index 778af895fc00..73f3cfe31d66 100644
--- a/drivers/gpu/drm/i915/i915_cgroup.c
+++ b/drivers/gpu/drm/i915/i915_cgroup.c
@@ -11,6 +11,8 @@
struct i915_cgroup_data {
struct cgroup_driver_data base;
+
+ int priority_offset;
};
static inline struct i915_cgroup_data *
@@ -72,6 +74,8 @@ i915_cgroup_setparam_ioctl(struct drm_device *dev, void *data,
struct cgroup *cgrp;
struct file *f;
struct inode *inode = NULL;
+ struct cgroup_driver_data *cgrpdata;
+ struct i915_cgroup_data *i915data;
int ret;
if (!dev_priv->i915_cgroups) {
@@ -125,6 +129,17 @@ i915_cgroup_setparam_ioctl(struct drm_device *dev, void *data,
return ret;
switch (req->param) {
+ case I915_CGROUP_PARAM_PRIORITY_OFFSET:
+ cgrpdata = cgroup_driver_get_data(dev_priv->i915_cgroups, cgrp,
+ NULL);
+ if (IS_ERR(cgrpdata))
+ return PTR_ERR(cgrpdata);
+
+ DRM_DEBUG_DRIVER("Setting cgroup priority offset to %lld\n",
+ req->value);
+ i915data = cgrp_to_i915(cgrpdata);
+ i915data->priority_offset = req->value;
+ break;
default:
DRM_DEBUG_DRIVER("Invalid cgroup parameter %lld\n", req->param);
return -EINVAL;
@@ -132,3 +147,34 @@ i915_cgroup_setparam_ioctl(struct drm_device *dev, void *data,
return 0;
}
+
+/**
+ * i915_cgroup_get_prio_offset() - get prio offset for current proc's cgroup
+ * @dev_priv: drm device
+ * @file_priv: file handle for calling process
+ *
+ * RETURNS:
+ * Priority offset associated with the calling process' cgroup in the default
+ * (v2) hierarchy, otherwise 0 if no explicit priority has been assigned.
+ */
+int
+i915_cgroup_get_prio_offset(struct drm_i915_private *dev_priv,
+ struct drm_i915_file_private *file_priv)
+{
+ struct cgroup *cgrp;
+ struct cgroup_driver_data *cgrpdata;
+
+ /* Ignore internally-created contexts not associated with a process */
+ if (!file_priv)
+ return 0;
+
+ cgrp = drm_file_get_cgroup(file_priv->file);
+ if (WARN_ON(!cgrp))
+ return 0;
+
+ cgrpdata = cgroup_driver_get_data(dev_priv->i915_cgroups, cgrp, NULL);
+ if (IS_ERR(cgrpdata))
+ return 0;
+
+ return cgrp_to_i915(cgrpdata)->priority_offset;
+}
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 60e3ff6a48bb..313191e5278a 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2920,6 +2920,8 @@ int i915_cgroup_init(struct drm_i915_private *dev_priv);
int i915_cgroup_setparam_ioctl(struct drm_device *dev, void *data,
struct drm_file *file);
void i915_cgroup_shutdown(struct drm_i915_private *dev_priv);
+int i915_cgroup_get_prio_offset(struct drm_i915_private *dev_priv,
+ struct drm_i915_file_private *file_priv);
#else
static inline int
i915_cgroup_init(struct drm_i915_private *dev_priv)
@@ -2933,6 +2935,11 @@ i915_cgroup_setparam_ioctl(struct drm_device *dev, void *data,
{
return -EINVAL;
}
+static inline int
+i915_cgroup_get_prio_offset(struct drm_i915_private *dev_priv,
+ struct drm_i915_file_private *file_priv) {
+ return 0;
+}
#endif
/* i915_drv.c */
diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
index 648e7536ff51..700d7bc7cfc8 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -274,7 +274,9 @@ __create_hw_context(struct drm_i915_private *dev_priv,
kref_init(&ctx->ref);
list_add_tail(&ctx->link, &dev_priv->contexts.list);
ctx->i915 = dev_priv;
- ctx->priority = I915_PRIORITY_NORMAL;
+ ctx->priority_offset =
+ i915_cgroup_get_prio_offset(dev_priv, file_priv);
+ ctx->priority = I915_PRIORITY_NORMAL + ctx->priority_offset;
INIT_RADIX_TREE(&ctx->handles_vma, GFP_KERNEL);
INIT_LIST_HEAD(&ctx->handles_list);
@@ -816,7 +818,7 @@ int i915_gem_context_setparam_ioctl(struct drm_device *dev, void *data,
!capable(CAP_SYS_NICE))
ret = -EPERM;
else
- ctx->priority = priority;
+ ctx->priority = priority + ctx->priority_offset;
}
break;
diff --git a/drivers/gpu/drm/i915/i915_gem_context.h b/drivers/gpu/drm/i915/i915_gem_context.h
index 4bfb72f8e1cb..4f1c95fca5c2 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.h
+++ b/drivers/gpu/drm/i915/i915_gem_context.h
@@ -147,6 +147,15 @@ struct i915_gem_context {
*/
int priority;
+ /**
+ * @priority_offset: priority offset
+ *
+ * A value, configured via cgroup, that sets the starting priority
+ * of the context. Any priority set explicitly via context parameter
+ * will be added to the priority offset.
+ */
+ int priority_offset;
+
/** ggtt_offset_bias: placement restriction for context objects */
u32 ggtt_offset_bias;
diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
index fe333ae1f0c6..1c1988e9fba5 100644
--- a/include/uapi/drm/i915_drm.h
+++ b/include/uapi/drm/i915_drm.h
@@ -1622,6 +1622,7 @@ struct drm_i915_cgroup_param {
__s32 cgroup_fd;
__u32 flags;
__u64 param;
+#define I915_CGROUP_PARAM_PRIORITY_OFFSET 0x1
__s64 value;
};
--
2.14.3
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