On 2019-08-29 2:05 a.m., Kenny Ho wrote:
> drm.lgpu
> A read-write nested-keyed file which exists on all cgroups.
> Each entry is keyed by the DRM device's major:minor.
>
> lgpu stands for logical GPU, it is an abstraction used to
> subdivide a physical DRM device for the purpose of resource
> management.
>
> The lgpu is a discrete quantity that is device specific (i.e.
> some DRM devices may have 64 lgpus while others may have 100
> lgpus.) The lgpu is a single quantity with two representations
> denoted by the following nested keys.
>
> ===== ========================================
> count Representing lgpu as anonymous resource
> list Representing lgpu as named resource
> ===== ========================================
>
> For example:
> 226:0 count=256 list=0-255
> 226:1 count=4 list=0,2,4,6
> 226:2 count=32 list=32-63
>
> lgpu is represented by a bitmap and uses the bitmap_parselist
> kernel function so the list key input format is a
> comma-separated list of decimal numbers and ranges.
>
> Consecutively set bits are shown as two hyphen-separated decimal
> numbers, the smallest and largest bit numbers set in the range.
> Optionally each range can be postfixed to denote that only parts
> of it should be set. The range will divided to groups of
> specific size.
> Syntax: range:used_size/group_size
> Example: 0-1023:2/256 ==> 0,1,256,257,512,513,768,769
>
> The count key is the hamming weight / hweight of the bitmap.
>
> Both count and list accept the max and default keywords.
>
> Some DRM devices may only support lgpu as anonymous resources.
> In such case, the significance of the position of the set bits
> in list will be ignored.
>
> This lgpu resource supports the 'allocation' resource
> distribution model.
>
> Change-Id: I1afcacf356770930c7f925df043e51ad06ceb98e
> Signed-off-by: Kenny Ho <kenny...@amd.com>
The description sounds reasonable to me and maps well to the CU masking
feature in our GPUs.
It would also allow us to do more coarse-grained masking for example to
guarantee balanced allocation of CUs across shader engines or
partitioning of memory bandwidth or CP pipes (if that is supported by
the hardware/firmware).
I can't comment on the code as I'm unfamiliar with the details of the
cgroup code.
Acked-by: Felix Kuehling <felix.kuehl...@amd.com>
> ---
> Documentation/admin-guide/cgroup-v2.rst | 46 ++++++++
> include/drm/drm_cgroup.h | 4 +
> include/linux/cgroup_drm.h | 6 ++
> kernel/cgroup/drm.c | 135 ++++++++++++++++++++++++
> 4 files changed, 191 insertions(+)
>
> diff --git a/Documentation/admin-guide/cgroup-v2.rst
> b/Documentation/admin-guide/cgroup-v2.rst
> index 87a195133eaa..57f18469bd76 100644
> --- a/Documentation/admin-guide/cgroup-v2.rst
> +++ b/Documentation/admin-guide/cgroup-v2.rst
> @@ -1958,6 +1958,52 @@ DRM Interface Files
> Set largest allocation for /dev/dri/card1 to 4MB
> echo "226:1 4m" > drm.buffer.peak.max
>
> + drm.lgpu
> + A read-write nested-keyed file which exists on all cgroups.
> + Each entry is keyed by the DRM device's major:minor.
> +
> + lgpu stands for logical GPU, it is an abstraction used to
> + subdivide a physical DRM device for the purpose of resource
> + management.
> +
> + The lgpu is a discrete quantity that is device specific (i.e.
> + some DRM devices may have 64 lgpus while others may have 100
> + lgpus.) The lgpu is a single quantity with two representations
> + denoted by the following nested keys.
> +
> + ===== ========================================
> + count Representing lgpu as anonymous resource
> + list Representing lgpu as named resource
> + ===== ========================================
> +
> + For example:
> + 226:0 count=256 list=0-255
> + 226:1 count=4 list=0,2,4,6
> + 226:2 count=32 list=32-63
> +
> + lgpu is represented by a bitmap and uses the bitmap_parselist
> + kernel function so the list key input format is a
> + comma-separated list of decimal numbers and ranges.
> +
> + Consecutively set bits are shown as two hyphen-separated decimal
> + numbers, the smallest and largest bit numbers set in the range.
> + Optionally each range can be postfixed to denote that only parts
> + of it should be set. The range will divided to groups of
> + specific size.
> + Syntax: range:used_size/group_size
> + Example: 0-1023:2/256 ==> 0,1,256,257,512,513,768,769
> +
> + The count key is the hamming weight / hweight of the bitmap.
> +
> + Both count and list accept the max and default keywords.
> +
> + Some DRM devices may only support lgpu as anonymous resources.
> + In such case, the significance of the position of the set bits
> + in list will be ignored.
> +
> + This lgpu resource supports the 'allocation' resource
> + distribution model.
> +
> GEM Buffer Ownership
> ~~~~~~~~~~~~~~~~~~~~
>
> diff --git a/include/drm/drm_cgroup.h b/include/drm/drm_cgroup.h
> index 6d9707e1eb72..a8d6be0b075b 100644
> --- a/include/drm/drm_cgroup.h
> +++ b/include/drm/drm_cgroup.h
> @@ -6,6 +6,7 @@
>
> #include <linux/cgroup_drm.h>
> #include <linux/workqueue.h>
> +#include <linux/types.h>
> #include <drm/ttm/ttm_bo_api.h>
> #include <drm/ttm/ttm_bo_driver.h>
>
> @@ -28,6 +29,9 @@ struct drmcg_props {
> s64 mem_highs_default[TTM_PL_PRIV+1];
>
> struct work_struct *mem_reclaim_wq[TTM_PL_PRIV];
> +
> + int lgpu_capacity;
> + DECLARE_BITMAP(lgpu_slots, MAX_DRMCG_LGPU_CAPACITY);
> };
>
> #ifdef CONFIG_CGROUP_DRM
> diff --git a/include/linux/cgroup_drm.h b/include/linux/cgroup_drm.h
> index c56cfe74d1a6..7b1cfc4ce4c3 100644
> --- a/include/linux/cgroup_drm.h
> +++ b/include/linux/cgroup_drm.h
> @@ -14,6 +14,8 @@
> /* limit defined per the way drm_minor_alloc operates */
> #define MAX_DRM_DEV (64 * DRM_MINOR_RENDER)
>
> +#define MAX_DRMCG_LGPU_CAPACITY 256
> +
> enum drmcg_mem_bw_attr {
> DRMCG_MEM_BW_ATTR_BYTE_MOVED, /* for calulating 'instantaneous' bw */
> DRMCG_MEM_BW_ATTR_ACCUM_US, /* for calulating 'instantaneous' bw */
> @@ -32,6 +34,7 @@ enum drmcg_res_type {
> DRMCG_TYPE_MEM_PEAK,
> DRMCG_TYPE_BANDWIDTH,
> DRMCG_TYPE_BANDWIDTH_PERIOD_BURST,
> + DRMCG_TYPE_LGPU,
> __DRMCG_TYPE_LAST,
> };
>
> @@ -58,6 +61,9 @@ struct drmcg_device_resource {
> s64 mem_bw_stats[__DRMCG_MEM_BW_ATTR_LAST];
> s64 mem_bw_limits_bytes_in_period;
> s64 mem_bw_limits_avg_bytes_per_us;
> +
> + s64 lgpu_used;
> + DECLARE_BITMAP(lgpu_allocated, MAX_DRMCG_LGPU_CAPACITY);
> };
>
> /**
> diff --git a/kernel/cgroup/drm.c b/kernel/cgroup/drm.c
> index 0ea7f0619e25..18c4368e2c29 100644
> --- a/kernel/cgroup/drm.c
> +++ b/kernel/cgroup/drm.c
> @@ -9,6 +9,7 @@
> #include <linux/cgroup_drm.h>
> #include <linux/ktime.h>
> #include <linux/kernel.h>
> +#include <linux/bitmap.h>
> #include <drm/drm_file.h>
> #include <drm/drm_drv.h>
> #include <drm/ttm/ttm_bo_api.h>
> @@ -52,6 +53,9 @@ static char const *mem_bw_attr_names[] = {
> #define MEM_BW_LIMITS_NAME_AVG "avg_bytes_per_us"
> #define MEM_BW_LIMITS_NAME_BURST "bytes_in_period"
>
> +#define LGPU_LIMITS_NAME_LIST "list"
> +#define LGPU_LIMITS_NAME_COUNT "count"
> +
> static struct drmcg *root_drmcg __read_mostly;
>
> static int drmcg_css_free_fn(int id, void *ptr, void *data)
> @@ -115,6 +119,10 @@ static inline int init_drmcg_single(struct drmcg *drmcg,
> struct drm_device *dev)
> for (i = 0; i <= TTM_PL_PRIV; i++)
> ddr->mem_highs[i] = dev->drmcg_props.mem_highs_default[i];
>
> + bitmap_copy(ddr->lgpu_allocated, dev->drmcg_props.lgpu_slots,
> + MAX_DRMCG_LGPU_CAPACITY);
> + ddr->lgpu_used = bitmap_weight(ddr->lgpu_allocated,
> MAX_DRMCG_LGPU_CAPACITY);
> +
> mutex_unlock(&dev->drmcg_mutex);
> return 0;
> }
> @@ -280,6 +288,14 @@ static void drmcg_print_limits(struct
> drmcg_device_resource *ddr,
> MEM_BW_LIMITS_NAME_AVG,
> ddr->mem_bw_limits_avg_bytes_per_us);
> break;
> + case DRMCG_TYPE_LGPU:
> + seq_printf(sf, "%s=%lld %s=%*pbl\n",
> + LGPU_LIMITS_NAME_COUNT,
> + ddr->lgpu_used,
> + LGPU_LIMITS_NAME_LIST,
> + dev->drmcg_props.lgpu_capacity,
> + ddr->lgpu_allocated);
> + break;
> default:
> seq_puts(sf, "\n");
> break;
> @@ -314,6 +330,15 @@ static void drmcg_print_default(struct drmcg_props
> *props,
> MEM_BW_LIMITS_NAME_AVG,
> props->mem_bw_avg_bytes_per_us_default);
> break;
> + case DRMCG_TYPE_LGPU:
> + seq_printf(sf, "%s=%d %s=%*pbl\n",
> + LGPU_LIMITS_NAME_COUNT,
> + bitmap_weight(props->lgpu_slots,
> + props->lgpu_capacity),
> + LGPU_LIMITS_NAME_LIST,
> + props->lgpu_capacity,
> + props->lgpu_slots);
> + break;
> default:
> seq_puts(sf, "\n");
> break;
> @@ -407,9 +432,21 @@ static void drmcg_value_apply(struct drm_device *dev,
> s64 *dst, s64 val)
> mutex_unlock(&dev->drmcg_mutex);
> }
>
> +static void drmcg_lgpu_values_apply(struct drm_device *dev,
> + struct drmcg_device_resource *ddr, unsigned long *val)
> +{
> +
> + mutex_lock(&dev->drmcg_mutex);
> + bitmap_copy(ddr->lgpu_allocated, val, MAX_DRMCG_LGPU_CAPACITY);
> + ddr->lgpu_used = bitmap_weight(ddr->lgpu_allocated,
> MAX_DRMCG_LGPU_CAPACITY);
> + mutex_unlock(&dev->drmcg_mutex);
> +}
> +
> static void drmcg_nested_limit_parse(struct kernfs_open_file *of,
> struct drm_device *dev, char *attrs)
> {
> + DECLARE_BITMAP(tmp_bitmap, MAX_DRMCG_LGPU_CAPACITY);
> + DECLARE_BITMAP(chk_bitmap, MAX_DRMCG_LGPU_CAPACITY);
> enum drmcg_res_type type =
> DRMCG_CTF_PRIV2RESTYPE(of_cft(of)->private);
> struct drmcg *drmcg = css_to_drmcg(of_css(of));
> @@ -501,6 +538,83 @@ static void drmcg_nested_limit_parse(struct
> kernfs_open_file *of,
> continue;
> }
> break; /* DRMCG_TYPE_MEM */
> + case DRMCG_TYPE_LGPU:
> + if (strncmp(sname, LGPU_LIMITS_NAME_LIST, 256) &&
> + strncmp(sname, LGPU_LIMITS_NAME_COUNT, 256) )
> + continue;
> +
> + if (!strcmp("max", sval) ||
> + !strcmp("default", sval)) {
> + if (parent != NULL)
> + drmcg_lgpu_values_apply(dev, ddr,
> + parent->dev_resources[minor]->
> + lgpu_allocated);
> + else
> + drmcg_lgpu_values_apply(dev, ddr,
> + props->lgpu_slots);
> +
> + continue;
> + }
> +
> + if (strncmp(sname, LGPU_LIMITS_NAME_COUNT, 256) == 0) {
> + p_max = parent == NULL ? props->lgpu_capacity:
> + bitmap_weight(
> + parent->dev_resources[minor]->
> + lgpu_allocated, props->lgpu_capacity);
> +
> + rc = drmcg_process_limit_s64_val(sval,
> + false, p_max, p_max, &val);
> +
> + if (rc || val < 0) {
> + drmcg_pr_cft_err(drmcg, rc, cft_name,
> + minor);
> + continue;
> + }
> +
> + bitmap_zero(tmp_bitmap,
> + MAX_DRMCG_LGPU_CAPACITY);
> + bitmap_set(tmp_bitmap, 0, val);
> + }
> +
> + if (strncmp(sname, LGPU_LIMITS_NAME_LIST, 256) == 0) {
> + rc = bitmap_parselist(sval, tmp_bitmap,
> + MAX_DRMCG_LGPU_CAPACITY);
> +
> + if (rc) {
> + drmcg_pr_cft_err(drmcg, rc, cft_name,
> + minor);
> + continue;
> + }
> +
> + bitmap_andnot(chk_bitmap, tmp_bitmap,
> + props->lgpu_slots,
> + MAX_DRMCG_LGPU_CAPACITY);
> +
> + if (!bitmap_empty(chk_bitmap,
> + MAX_DRMCG_LGPU_CAPACITY)) {
> + drmcg_pr_cft_err(drmcg, 0, cft_name,
> + minor);
> + continue;
> + }
> + }
> +
> +
> + if (parent != NULL) {
> + bitmap_and(chk_bitmap, tmp_bitmap,
> + parent->dev_resources[minor]->lgpu_allocated,
> + props->lgpu_capacity);
> +
> + if (bitmap_empty(chk_bitmap,
> + props->lgpu_capacity)) {
> + drmcg_pr_cft_err(drmcg, 0,
> + cft_name, minor);
> + continue;
> + }
> + }
> +
> + drmcg_lgpu_values_apply(dev, ddr, tmp_bitmap);
> +
> + break; /* DRMCG_TYPE_LGPU */
> default:
> break;
> } /* switch (type) */
> @@ -606,6 +720,7 @@ static ssize_t drmcg_limit_write(struct kernfs_open_file
> *of, char *buf,
> break;
> case DRMCG_TYPE_BANDWIDTH:
> case DRMCG_TYPE_MEM:
> + case DRMCG_TYPE_LGPU:
> drmcg_nested_limit_parse(of, dm->dev, sattr);
> break;
> default:
> @@ -731,6 +846,20 @@ struct cftype files[] = {
> .private = DRMCG_CTF_PRIV(DRMCG_TYPE_BANDWIDTH,
> DRMCG_FTYPE_DEFAULT),
> },
> + {
> + .name = "lgpu",
> + .seq_show = drmcg_seq_show,
> + .write = drmcg_limit_write,
> + .private = DRMCG_CTF_PRIV(DRMCG_TYPE_LGPU,
> + DRMCG_FTYPE_LIMIT),
> + },
> + {
> + .name = "lgpu.default",
> + .seq_show = drmcg_seq_show,
> + .flags = CFTYPE_ONLY_ON_ROOT,
> + .private = DRMCG_CTF_PRIV(DRMCG_TYPE_LGPU,
> + DRMCG_FTYPE_DEFAULT),
> + },
> { } /* terminate */
> };
>
> @@ -744,6 +873,10 @@ struct cgroup_subsys drm_cgrp_subsys = {
>
> static inline void drmcg_update_cg_tree(struct drm_device *dev)
> {
> + bitmap_zero(dev->drmcg_props.lgpu_slots, MAX_DRMCG_LGPU_CAPACITY);
> + bitmap_fill(dev->drmcg_props.lgpu_slots,
> + dev->drmcg_props.lgpu_capacity);
> +
> /* init cgroups created before registration (i.e. root cgroup) */
> if (root_drmcg != NULL) {
> struct cgroup_subsys_state *pos;
> @@ -800,6 +933,8 @@ void drmcg_device_early_init(struct drm_device *dev)
> for (i = 0; i <= TTM_PL_PRIV; i++)
> dev->drmcg_props.mem_highs_default[i] = S64_MAX;
>
> + dev->drmcg_props.lgpu_capacity = MAX_DRMCG_LGPU_CAPACITY;
> +
> drmcg_update_cg_tree(dev);
> }
> EXPORT_SYMBOL(drmcg_device_early_init);
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