[PATCH v2 09/11] drm, cgroup: Add compute as gpu cgroup resource

Kenny Ho
2020-02-26T19:01:50Z

gpu.compute.weight
A read-write flat-keyed file which exists on all cgroups. The
default weight is 100. Each entry is keyed by the DRM device's
major:minor (the primary minor). The weights are in the range [1,
10000] and specifies the relative amount of physical partitions
the cgroup can use in relation to its siblings. The partition
concept here is analogous to the subdevice of OpenCL.

gpu.compute.effective
A read-only nested-keyed file which exists on all cgroups. Each
entry is keyed by the DRM device's major:minor.

It lists the GPU subdevices that are actually granted to this
cgroup by its parent. These subdevices are allowed to be used by
tasks within the current cgroup.

===== ==============================================
count The total number of granted subdevices
list Enumeration of the subdevices
===== ==============================================

Change-Id: Idde0ef9a331fd67bb9c7eb8ef9978439e6452488
Signed-off-by: Kenny Ho <Kenny.Ho-5C7GfCeVMHo@public.gmane.org>
---
Documentation/admin-guide/cgroup-v2.rst | 21 +++
include/drm/drm_cgroup.h | 3 +
include/linux/cgroup_drm.h | 16 +++
kernel/cgroup/drm.c | 177 +++++++++++++++++++++++-
4 files changed, 215 insertions(+), 2 deletions(-)

diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst
index 581343472651..f92f1f4a64d4 100644
--- a/Documentation/admin-guide/cgroup-v2.rst
+++ b/Documentation/admin-guide/cgroup-v2.rst
@@ -2126,6 +2126,27 @@ GPU Interface Files
Set largest allocation for /dev/dri/card1 to 4MB
echo "226:1 4m" > gpu.buffer.peak.max

+ gpu.compute.weight
+ A read-write flat-keyed file which exists on all cgroups. The
+ default weight is 100. Each entry is keyed by the DRM device's
+ major:minor (the primary minor). The weights are in the range
+ [1, 10000] and specifies the relative amount of physical partitions
+ the cgroup can use in relation to its siblings. The partition
+ concept here is analogous to the subdevice concept of OpenCL.
+
+ gpu.compute.effective
+ A read-only nested-keyed file which exists on all cgroups.
+ Each entry is keyed by the DRM device's major:minor.
+
+ It lists the GPU subdevices that are actually granted to this
+ cgroup by its parent. These subdevices are allowed to be used
+ by tasks within the current cgroup.
+
+ ===== ==============================================
+ count The total number of granted subdevices
+ list Enumeration of the subdevices
+ ===== ==============================================
+
GEM Buffer Ownership
~~~~~~~~~~~~~~~~~~~~

diff --git a/include/drm/drm_cgroup.h b/include/drm/drm_cgroup.h
index 2b41d4d22e33..5aac47ca536f 100644
--- a/include/drm/drm_cgroup.h
+++ b/include/drm/drm_cgroup.h
@@ -17,6 +17,9 @@ struct drmcg_props {

s64 bo_limits_total_allocated_default;
s64 bo_limits_peak_allocated_default;
+
+ int compute_capacity;
+ DECLARE_BITMAP(compute_slots, MAX_DRMCG_COMPUTE_CAPACITY);
};

void drmcg_bind(struct drm_minor (*(*acq_dm)(unsigned int minor_id)),
diff --git a/include/linux/cgroup_drm.h b/include/linux/cgroup_drm.h
index aba3b26718c0..fd02f59cabab 100644
--- a/include/linux/cgroup_drm.h
+++ b/include/linux/cgroup_drm.h
@@ -11,10 +11,14 @@
/* limit defined per the way drm_minor_alloc operates */
#define MAX_DRM_DEV (64 * DRM_MINOR_RENDER)

+#define MAX_DRMCG_COMPUTE_CAPACITY 256
+
enum drmcg_res_type {
DRMCG_TYPE_BO_TOTAL,
DRMCG_TYPE_BO_PEAK,
DRMCG_TYPE_BO_COUNT,
+ DRMCG_TYPE_COMPUTE,
+ DRMCG_TYPE_COMPUTE_EFF,
__DRMCG_TYPE_LAST,
};

@@ -32,6 +36,18 @@ struct drmcg_device_resource {
s64 bo_limits_peak_allocated;

s64 bo_stats_count_allocated;
+
+ /* compute_stg is used to calculate _eff before applying to _eff
+ * after considering the entire hierarchy
+ */
+ DECLARE_BITMAP(compute_stg, MAX_DRMCG_COMPUTE_CAPACITY);
+ /* user configurations */
+ s64 compute_weight;
+ /* effective compute for the cgroup after considering
+ * relationship with other cgroup
+ */
+ s64 compute_count_eff;
+ DECLARE_BITMAP(compute_eff, MAX_DRMCG_COMPUTE_CAPACITY);
};

/**
diff --git a/kernel/cgroup/drm.c b/kernel/cgroup/drm.c
index 62d2a9d33d0c..2eadabebdfea 100644
--- a/kernel/cgroup/drm.c
+++ b/kernel/cgroup/drm.c
@@ -9,6 +9,7 @@
#include <linux/seq_file.h>
#include <linux/mutex.h>
#include <linux/kernel.h>
+#include <linux/bitmap.h>
#include <linux/cgroup_drm.h>
#include <drm/drm_file.h>
#include <drm/drm_drv.h>
@@ -98,6 +99,11 @@ static inline int init_drmcg_single(struct drmcg *drmcg, struct drm_device *dev)
ddr->bo_limits_peak_allocated =
dev->drmcg_props.bo_limits_peak_allocated_default;

+ bitmap_copy(ddr->compute_stg, dev->drmcg_props.compute_slots,
+ MAX_DRMCG_COMPUTE_CAPACITY);
+
+ ddr->compute_weight = CGROUP_WEIGHT_DFL;
+
return 0;
}

@@ -121,6 +127,104 @@ static inline void drmcg_update_cg_tree(struct drm_device *dev)
mutex_unlock(&cgroup_mutex);
}

+static void drmcg_calculate_effective_compute(struct drm_device *dev,
+ const unsigned long *free_weighted,
+ struct drmcg *parent_drmcg)
+{
+ int capacity = dev->drmcg_props.compute_capacity;
+ DECLARE_BITMAP(compute_unused, MAX_DRMCG_COMPUTE_CAPACITY);
+ DECLARE_BITMAP(compute_by_weight, MAX_DRMCG_COMPUTE_CAPACITY);
+ struct drmcg_device_resource *parent_ddr;
+ struct drmcg_device_resource *ddr;
+ int minor = dev->primary->index;
+ struct cgroup_subsys_state *pos;
+ struct drmcg *child;
+ s64 weight_sum = 0;
+ s64 unused;
+
+ parent_ddr = parent_drmcg->dev_resources[minor];
+
+ /* no static cfg, use weight for calculating the effective */
+ bitmap_copy(parent_ddr->compute_stg, free_weighted, capacity);
+
+ /* calculate compute available for dist by weight for children */
+ bitmap_copy(compute_unused, parent_ddr->compute_stg, capacity);
+ unused = bitmap_weight(compute_unused, capacity);
+ css_for_each_child(pos, &parent_drmcg->css) {
+ child = css_to_drmcg(pos);
+ ddr = child->dev_resources[minor];
+
+ /* no static allocation, participate in weight dist */
+ weight_sum += ddr->compute_weight;
+ }
+
+ css_for_each_child(pos, &parent_drmcg->css) {
+ int c;
+ int p = 0;
+ child = css_to_drmcg(pos);
+ ddr = child->dev_resources[minor];
+
+ bitmap_zero(compute_by_weight, capacity);
+ for (c = ddr->compute_weight * unused / weight_sum;
+ c > 0; c--) {
+ p = find_next_bit(compute_unused, capacity, p);
+ if (p < capacity) {
+ clear_bit(p, compute_unused);
+ set_bit(p, compute_by_weight);
+ }
+ }
+
+ drmcg_calculate_effective_compute(dev, compute_by_weight, child);
+ }
+}
+
+static void drmcg_apply_effective_compute(struct drm_device *dev)
+{
+ int capacity = dev->drmcg_props.compute_capacity;
+ int minor = dev->primary->index;
+ struct drmcg_device_resource *ddr;
+ struct cgroup_subsys_state *pos;
+ struct drmcg *drmcg;
+
+ if (root_drmcg == NULL) {
+ WARN_ON(root_drmcg == NULL);
+ return;
+ }
+
+ rcu_read_lock();
+
+ /* process the entire cgroup tree from root to simplify the algorithm */
+ drmcg_calculate_effective_compute(dev, dev->drmcg_props.compute_slots,
+ root_drmcg);
+
+ /* apply changes to effective only if there is a change */
+ css_for_each_descendant_pre(pos, &root_drmcg->css) {
+ drmcg = css_to_drmcg(pos);
+ ddr = drmcg->dev_resources[minor];
+
+ if (!bitmap_equal(ddr->compute_stg,
+ ddr->compute_eff, capacity)) {
+ bitmap_copy(ddr->compute_eff, ddr->compute_stg,
+ capacity);
+ ddr->compute_count_eff =
+ bitmap_weight(ddr->compute_eff, capacity);
+ }
+ }
+ rcu_read_unlock();
+}
+
+static void drmcg_apply_effective(enum drmcg_res_type type,
+ struct drm_device *dev, struct drmcg *changed_drmcg)
+{
+ switch (type) {
+ case DRMCG_TYPE_COMPUTE:
+ drmcg_apply_effective_compute(dev);
+ break;
+ default:
+ break;
+ }
+}
+
/**
* drmcg_register_dev - register a DRM device for usage in drm cgroup
* @dev: DRM device
@@ -143,7 +247,13 @@ void drmcg_register_dev(struct drm_device *dev)
{
dev->driver->drmcg_custom_init(dev, &dev->drmcg_props);

+ WARN_ON(dev->drmcg_props.compute_capacity !=
+ bitmap_weight(dev->drmcg_props.compute_slots,
+ MAX_DRMCG_COMPUTE_CAPACITY));
+
drmcg_update_cg_tree(dev);
+
+ drmcg_apply_effective(DRMCG_TYPE_COMPUTE, dev, root_drmcg);
}
mutex_unlock(&drmcg_mutex);
}
@@ -297,7 +407,8 @@ static void drmcg_print_stats(struct drmcg_device_resource *ddr,
}

static void drmcg_print_limits(struct drmcg_device_resource *ddr,
- struct seq_file *sf, enum drmcg_res_type type)
+ struct seq_file *sf, enum drmcg_res_type type,
+ struct drm_device *dev)
{
if (ddr == NULL) {
seq_puts(sf, "\n");
@@ -311,6 +422,17 @@ static void drmcg_print_limits(struct drmcg_device_resource *ddr,
case DRMCG_TYPE_BO_PEAK:
seq_printf(sf, "%lld\n", ddr->bo_limits_peak_allocated);
break;
+ case DRMCG_TYPE_COMPUTE:
+ seq_printf(sf, "%lld\n", ddr->compute_weight);
+ break;
+ case DRMCG_TYPE_COMPUTE_EFF:
+ seq_printf(sf, "%s=%lld %s=%*pbl\n",
+ "count",
+ ddr->compute_count_eff,
+ "list",
+ dev->drmcg_props.compute_capacity,
+ ddr->compute_eff);
+ break;
default:
seq_puts(sf, "\n");
break;
@@ -358,7 +480,7 @@ static int drmcg_seq_show_fn(int id, void *ptr, void *data)
drmcg_print_stats(ddr, sf, type);
break;
case DRMCG_FTYPE_LIMIT:
- drmcg_print_limits(ddr, sf, type);
+ drmcg_print_limits(ddr, sf, type, minor->dev);
break;
case DRMCG_FTYPE_DEFAULT:
drmcg_print_default(&minor->dev->drmcg_props, sf, type);
@@ -499,9 +621,25 @@ static ssize_t drmcg_limit_write(struct kernfs_open_file *of, char *buf,

ddr->bo_limits_peak_allocated = val;
break;
+ case DRMCG_TYPE_COMPUTE:
+ rc = drmcg_process_limit_s64_val(sattr, true,
+ CGROUP_WEIGHT_DFL, CGROUP_WEIGHT_MAX,
+ &val);
+
+ if (rc || val < CGROUP_WEIGHT_MIN ||
+ val > CGROUP_WEIGHT_MAX) {
+ drmcg_pr_cft_err(drmcg, rc, cft_name, minor);
+ break;
+ }
+
+ ddr->compute_weight = val;
+ break;
default:
break;
}
+
+ drmcg_apply_effective(type, dm->dev, drmcg);
+
mutex_unlock(&dm->dev->drmcg_mutex);

mutex_lock(&drmcg_mutex);
@@ -560,12 +698,44 @@ struct cftype files[] = {
.private = DRMCG_CTF_PRIV(DRMCG_TYPE_BO_COUNT,
DRMCG_FTYPE_STATS),
},
+ {
+ .name = "compute.weight",
+ .seq_show = drmcg_seq_show,
+ .write = drmcg_limit_write,
+ .private = DRMCG_CTF_PRIV(DRMCG_TYPE_COMPUTE,
+ DRMCG_FTYPE_LIMIT),
+ },
+ {
+ .name = "compute.effective",
+ .seq_show = drmcg_seq_show,
+ .private = DRMCG_CTF_PRIV(DRMCG_TYPE_COMPUTE_EFF,
+ DRMCG_FTYPE_LIMIT),
+ },
{ } /* terminate */
};

+static int drmcg_online_fn(int id, void *ptr, void *data)
+{
+ struct drm_minor *minor = ptr;
+ struct drmcg *drmcg = data;
+
+ if (minor->type != DRM_MINOR_PRIMARY)
+ return 0;
+
+ drmcg_apply_effective(DRMCG_TYPE_COMPUTE, minor->dev, drmcg);
+
+ return 0;
+}
+
+static int drmcg_css_online(struct cgroup_subsys_state *css)
+{
+ return drm_minor_for_each(&drmcg_online_fn, css_to_drmcg(css));
+}
+
struct cgroup_subsys gpu_cgrp_subsys = {
.css_alloc = drmcg_css_alloc,
.css_free = drmcg_css_free,
+ .css_online = drmcg_css_online,
.early_init = false,
.legacy_cftypes = files,
.dfl_cftypes = files,
@@ -585,6 +755,9 @@ void drmcg_device_early_init(struct drm_device *dev)
dev->drmcg_props.bo_limits_total_allocated_default = S64_MAX;
dev->drmcg_props.bo_limits_peak_allocated_default = S64_MAX;

+ dev->drmcg_props.compute_capacity = MAX_DRMCG_COMPUTE_CAPACITY;
+ bitmap_fill(dev->drmcg_props.compute_slots, MAX_DRMCG_COMPUTE_CAPACITY);
+
drmcg_update_cg_tree(dev);
}
EXPORT_SYMBOL(drmcg_device_early_init);
--
2.25.0