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.
v2:
- Rebase onto new cgroup_priv API
- Use current instead of drm_file->pid to determine which process to
lookup priority for. (Chris)
- Don't forget to subtract priority offset in context_getparam ioctl to
make it match setparam behavior. (Chris)
Signed-off-by: Matt Roper <matthew.d.roper@xxxxxxxxx>
---
drivers/gpu/drm/i915/i915_cgroup.c | 47 +++++++++++++++++++++++++++++++++
drivers/gpu/drm/i915/i915_drv.h | 15 ++++++-----
drivers/gpu/drm/i915/i915_gem_context.c | 7 ++---
drivers/gpu/drm/i915/i915_gem_context.h | 9 +++++++
include/uapi/drm/i915_drm.h | 1 +
5 files changed, 69 insertions(+), 10 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_cgroup.c b/drivers/gpu/drm/i915/i915_cgroup.c
index 4a46cb167f53..6a28b1a23971 100644
--- a/drivers/gpu/drm/i915/i915_cgroup.c
+++ b/drivers/gpu/drm/i915/i915_cgroup.c
@@ -13,6 +13,8 @@ struct i915_cgroup_data {
struct cgroup_priv base;
struct list_head node;
+
+ int priority_offset;
};
static inline struct i915_cgroup_data *
@@ -117,8 +119,10 @@ i915_cgroup_setparam_ioctl(struct drm_device *dev,
void *data,
struct drm_file *file)
{
+ struct drm_i915_private *dev_priv = to_i915(dev);
struct drm_i915_cgroup_param *req = data;
struct cgroup *cgrp;
+ struct i915_cgroup_data *cgrpdata;
int ret;
/* We don't actually support any flags yet. */
@@ -154,7 +158,18 @@ i915_cgroup_setparam_ioctl(struct drm_device *dev,
if (ret)
goto out;
+ cgrpdata = get_or_create_cgroup_data(dev_priv, cgrp);
+ if (IS_ERR(cgrpdata)) {
+ ret = PTR_ERR(cgrpdata);
+ goto out;
+ }
+
switch (req->param) {
+ case I915_CGROUP_PARAM_PRIORITY_OFFSET:
+ DRM_DEBUG_DRIVER("Setting cgroup priority offset to %lld\n",
+ req->value);
+ cgrpdata->priority_offset = req->value;
+ break;
default:
DRM_DEBUG_DRIVER("Invalid cgroup parameter %lld\n", req->param);
ret = -EINVAL;
@@ -165,3 +180,35 @@ i915_cgroup_setparam_ioctl(struct drm_device *dev,
return ret;
}
+
+/**
+ * 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_current_prio_offset(struct drm_i915_private *dev_priv)
+{
+ struct cgroup *cgrp;
+ struct cgroup_priv *cgrpdata;
+ int offset = 0;
+
+ cgrp = task_get_dfl_cgroup(current);
+ if (WARN_ON(!cgrp))
+ return 0;
+
+ mutex_lock(&cgrp->privdata_mutex);
+
+ cgrpdata = cgroup_priv_lookup(cgrp, dev_priv);
+ if (cgrpdata)
+ offset = cgrp_to_i915(cgrpdata)->priority_offset;
+
+ mutex_unlock(&cgrp->privdata_mutex);
+ cgroup_put(cgrp);
+
+ return offset;
+}
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 7c38142ee009..51b80926d20c 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2947,18 +2947,19 @@ void 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_current_prio_offset(struct drm_i915_private *dev_priv);
#else
-static inline int
-i915_cgroup_init(struct drm_i915_private *dev_priv)
+static inline void i915_cgroup_init(struct drm_i915_private *dev_priv) {}
+static inline void i915_cgroup_shutdown(struct drm_i915_private *dev_priv) {}
+static inline int i915_cgroup_setparam_ioctl(struct drm_device *dev, void *data,
+ struct drm_file *file)
{
- return 0;
+ return -EINVAL;
}
-static inline void i915_cgroup_shutdown(struct drm_i915_private *dev_priv) {}
static inline int
-i915_cgroup_setparam_ioctl(struct drm_device *dev, void *data,
- struct drm_file *file)
+i915_cgroup_get_current_prio_offset(struct drm_i915_private *dev_priv)
{
- return -EINVAL;
+ return 0;
}
#endif
diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
index a73340ae9419..b29fbe0c776f 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -274,7 +274,8 @@ __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_current_prio_offset(dev_priv);
+ ctx->priority = I915_PRIORITY_NORMAL + ctx->priority_offset;
INIT_RADIX_TREE(&ctx->handles_vma, GFP_KERNEL);
INIT_LIST_HEAD(&ctx->handles_list);
@@ -739,7 +740,7 @@ int i915_gem_context_getparam_ioctl(struct drm_device *dev, void *data,
args->value = i915_gem_context_is_bannable(ctx);
break;
case I915_CONTEXT_PARAM_PRIORITY:
- args->value = ctx->priority;
+ args->value = ctx->priority - ctx->priority_offset;
break;
default:
ret = -EINVAL;
@@ -812,7 +813,7 @@ 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 7854262ddfd9..c3b4fb54fbb6 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.h
+++ b/drivers/gpu/drm/i915/i915_gem_context.h
@@ -150,6 +150,15 @@ 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 b6651b263838..5b67aaf8a1c0 100644
--- a/include/uapi/drm/i915_drm.h
+++ b/include/uapi/drm/i915_drm.h
@@ -1624,6 +1624,7 @@ 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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