[RFC PATCH v3 08/11] drm, cgroup: Add TTM buffer peak usage stats

[Kenny Ho]

drm.memory.peak.stats
        A read-only nested-keyed file which exists on all cgroups.
        Each entry is keyed by the drm device's major:minor.  The
        following nested keys are defined.

          ======         ==============================================
          system         Peak host memory used
          tt             Peak host memory used by the device (GTT/GART)
          vram           Peak Video RAM used by the drm device
          priv           Other drm device specific memory peak usage
          ======         ==============================================

        Reading returns the following::

        226:0 system=0 tt=0 vram=0 priv=0
        226:1 system=0 tt=9035776 vram=17768448 priv=16809984
        226:2 system=0 tt=9035776 vram=17768448 priv=16809984

Change-Id: I986e44533848f66411465bdd52105e78105a709a
Signed-off-by: Kenny Ho <Kenny.Ho at amd.com>
---
 include/linux/cgroup_drm.h |  1 +
 kernel/cgroup/drm.c        | 20 ++++++++++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/include/linux/cgroup_drm.h b/include/linux/cgroup_drm.h
index 141bea06f74c..922529641df5 100644
--- a/include/linux/cgroup_drm.h
+++ b/include/linux/cgroup_drm.h
@@ -25,6 +25,7 @@ struct drmcgrp_device_resource {
 	s64			bo_stats_count_allocated;
 
 	s64			mem_stats[TTM_PL_PRIV+1];
+	s64			mem_peaks[TTM_PL_PRIV+1];
 	s64			mem_stats_evict;
 };
 
diff --git a/kernel/cgroup/drm.c b/kernel/cgroup/drm.c
index 5aee42a628c1..5f5fa6a2b068 100644
--- a/kernel/cgroup/drm.c
+++ b/kernel/cgroup/drm.c
@@ -38,6 +38,7 @@ enum drmcgrp_res_type {
 	DRMCGRP_TYPE_BO_COUNT,
 	DRMCGRP_TYPE_MEM,
 	DRMCGRP_TYPE_MEM_EVICT,
+	DRMCGRP_TYPE_MEM_PEAK,
 };
 
 enum drmcgrp_file_type {
@@ -171,6 +172,13 @@ static inline void drmcgrp_print_stats(struct drmcgrp_device_resource *ddr,
 	case DRMCGRP_TYPE_MEM_EVICT:
 		seq_printf(sf, "%lld\n", ddr->mem_stats_evict);
 		break;
+	case DRMCGRP_TYPE_MEM_PEAK:
+		for (i = 0; i <= TTM_PL_PRIV; i++) {
+			seq_printf(sf, "%s=%lld ", ttm_placement_names[i],
+					ddr->mem_peaks[i]);
+		}
+		seq_puts(sf, "\n");
+		break;
 	default:
 		seq_puts(sf, "\n");
 		break;
@@ -440,6 +448,12 @@ struct cftype files[] = {
 		.private = DRMCG_CTF_PRIV(DRMCGRP_TYPE_MEM_EVICT,
 						DRMCGRP_FTYPE_STATS),
 	},
+	{
+		.name = "memory.peaks.stats",
+		.seq_show = drmcgrp_bo_show,
+		.private = DRMCG_CTF_PRIV(DRMCGRP_TYPE_MEM_PEAK,
+						DRMCGRP_FTYPE_STATS),
+	},
 	{ }	/* terminate */
 };
 
@@ -608,6 +622,8 @@ void drmcgrp_chg_mem(struct ttm_buffer_object *tbo)
 	for ( ; drmcgrp != NULL; drmcgrp = parent_drmcgrp(drmcgrp)) {
 		ddr = drmcgrp->dev_resources[devIdx];
 		ddr->mem_stats[mem_type] += size;
+		ddr->mem_peaks[mem_type] = max(ddr->mem_peaks[mem_type],
+				ddr->mem_stats[mem_type]);
 	}
 	mutex_unlock(&known_drmcgrp_devs[devIdx]->mutex);
 }
@@ -662,6 +678,10 @@ void drmcgrp_mem_track_move(struct ttm_buffer_object *old_bo, bool evict,
 		ddr->mem_stats[old_mem_type] -= move_in_bytes;
 		ddr->mem_stats[new_mem_type] += move_in_bytes;
 
+		ddr->mem_peaks[new_mem_type] = max(
+				ddr->mem_peaks[new_mem_type],
+				ddr->mem_stats[new_mem_type]);
+
 		if (evict)
 			ddr->mem_stats_evict++;
 	}
-- 
2.21.0