[PATCH RFC v4 13/16] drm, cgroup: Allow more aggressive memory reclaim

[Kenny Ho <Kenny.Ho-5C7GfCeVMHo@public.gmane.org>]

Allow DRM TTM memory manager to register a work_struct, such that, when
a drmcgrp is under memory pressure, memory reclaiming can be triggered
immediately.

Change-Id: I25ac04e2db9c19ff12652b88ebff18b44b2706d8
Signed-off-by: Kenny Ho <Kenny.Ho@amd.com>
---
 drivers/gpu/drm/ttm/ttm_bo.c    | 49 +++++++++++++++++++++++++++++++++
 include/drm/drm_cgroup.h        | 16 +++++++++++
 include/drm/ttm/ttm_bo_driver.h |  2 ++
 kernel/cgroup/drm.c             | 30 ++++++++++++++++++++
 4 files changed, 97 insertions(+)

diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index d7e3d3128ebb..72efae694b7e 100644
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -1590,6 +1590,46 @@ int ttm_bo_evict_mm(struct ttm_bo_device *bdev, unsigned mem_type)
 }
 EXPORT_SYMBOL(ttm_bo_evict_mm);
 
+static void ttm_bo_reclaim_wq(struct work_struct *work)
+{
+	struct ttm_operation_ctx ctx = {
+		.interruptible = false,
+		.no_wait_gpu = false,
+		.flags = TTM_OPT_FLAG_FORCE_ALLOC
+	};
+	struct ttm_mem_type_manager *man =
+	    container_of(work, struct ttm_mem_type_manager, reclaim_wq);
+	struct ttm_bo_device *bdev = man->bdev;
+	struct dma_fence *fence;
+	int mem_type;
+	int ret;
+
+	for (mem_type = 0; mem_type < TTM_NUM_MEM_TYPES; mem_type++)
+		if (&bdev->man[mem_type] == man)
+			break;
+
+	WARN_ON(mem_type >= TTM_NUM_MEM_TYPES);
+	if (mem_type >= TTM_NUM_MEM_TYPES)
+		return;
+
+	if (!drmcg_mem_pressure_scan(bdev, mem_type))
+		return;
+
+	ret = ttm_mem_evict_first(bdev, mem_type, NULL, &ctx, NULL);
+	if (ret)
+		return;
+
+	spin_lock(&man->move_lock);
+	fence = dma_fence_get(man->move);
+	spin_unlock(&man->move_lock);
+
+	if (fence) {
+		ret = dma_fence_wait(fence, false);
+		dma_fence_put(fence);
+	}
+
+}
+
 int ttm_bo_init_mm(struct ttm_bo_device *bdev, unsigned type,
 			unsigned long p_size)
 {
@@ -1624,6 +1664,13 @@ int ttm_bo_init_mm(struct ttm_bo_device *bdev, unsigned type,
 		INIT_LIST_HEAD(&man->lru[i]);
 	man->move = NULL;
 
+	pr_err("drmcg %p type %d\n", bdev->ddev, type);
+
+	if (type <= TTM_PL_VRAM) {
+		INIT_WORK(&man->reclaim_wq, ttm_bo_reclaim_wq);
+		drmcg_register_device_mm(bdev->ddev, type, &man->reclaim_wq);
+	}
+
 	return 0;
 }
 EXPORT_SYMBOL(ttm_bo_init_mm);
@@ -1701,6 +1748,8 @@ int ttm_bo_device_release(struct ttm_bo_device *bdev)
 		man = &bdev->man[i];
 		if (man->has_type) {
 			man->use_type = false;
+			drmcg_unregister_device_mm(bdev->ddev, i);
+			cancel_work_sync(&man->reclaim_wq);
 			if ((i != TTM_PL_SYSTEM) && ttm_bo_clean_mm(bdev, i)) {
 				ret = -EBUSY;
 				pr_err("DRM memory manager type %d is not clean\n",
diff --git a/include/drm/drm_cgroup.h b/include/drm/drm_cgroup.h
index c11df388fdf2..6d9707e1eb72 100644
--- a/include/drm/drm_cgroup.h
+++ b/include/drm/drm_cgroup.h
@@ -5,6 +5,7 @@
 #define __DRM_CGROUP_H__
 
 #include <linux/cgroup_drm.h>
+#include <linux/workqueue.h>
 #include <drm/ttm/ttm_bo_api.h>
 #include <drm/ttm/ttm_bo_driver.h>
 
@@ -25,12 +26,17 @@ struct drmcg_props {
 	s64			mem_bw_avg_bytes_per_us_default;
 
 	s64			mem_highs_default[TTM_PL_PRIV+1];
+
+	struct work_struct	*mem_reclaim_wq[TTM_PL_PRIV];
 };
 
 #ifdef CONFIG_CGROUP_DRM
 
 void drmcg_device_update(struct drm_device *device);
 void drmcg_device_early_init(struct drm_device *device);
+void drmcg_register_device_mm(struct drm_device *dev, unsigned int type,
+		struct work_struct *wq);
+void drmcg_unregister_device_mm(struct drm_device *dev, unsigned int type);
 bool drmcg_try_chg_bo_alloc(struct drmcg *drmcg, struct drm_device *dev,
 		size_t size);
 void drmcg_unchg_bo_alloc(struct drmcg *drmcg, struct drm_device *dev,
@@ -53,6 +59,16 @@ static inline void drmcg_device_early_init(struct drm_device *device)
 {
 }
 
+static inline void drmcg_register_device_mm(struct drm_device *dev,
+		unsigned int type, struct work_struct *wq)
+{
+}
+
+static inline void drmcg_unregister_device_mm(struct drm_device *dev,
+		unsigned int type)
+{
+}
+
 static inline void drmcg_try_chg_bo_alloc(struct drmcg *drmcg,
 		struct drm_device *dev,	size_t size)
 {
diff --git a/include/drm/ttm/ttm_bo_driver.h b/include/drm/ttm/ttm_bo_driver.h
index e1a805d65b83..529cef92bcf6 100644
--- a/include/drm/ttm/ttm_bo_driver.h
+++ b/include/drm/ttm/ttm_bo_driver.h
@@ -205,6 +205,8 @@ struct ttm_mem_type_manager {
 	 * Protected by @move_lock.
 	 */
 	struct dma_fence *move;
+
+	struct work_struct reclaim_wq;
 };
 
 /**
diff --git a/kernel/cgroup/drm.c b/kernel/cgroup/drm.c
index 04fb9a398740..0ea7f0619e25 100644
--- a/kernel/cgroup/drm.c
+++ b/kernel/cgroup/drm.c
@@ -804,6 +804,29 @@ void drmcg_device_early_init(struct drm_device *dev)
 }
 EXPORT_SYMBOL(drmcg_device_early_init);
 
+void drmcg_register_device_mm(struct drm_device *dev, unsigned int type,
+		struct work_struct *wq)
+{
+	if (dev == NULL || type >= TTM_PL_PRIV)
+		return;
+
+	mutex_lock(&drmcg_mutex);
+	dev->drmcg_props.mem_reclaim_wq[type] = wq;
+	mutex_unlock(&drmcg_mutex);
+}
+EXPORT_SYMBOL(drmcg_register_device_mm);
+
+void drmcg_unregister_device_mm(struct drm_device *dev, unsigned int type)
+{
+	if (dev == NULL || type >= TTM_PL_PRIV)
+		return;
+
+	mutex_lock(&drmcg_mutex);
+	dev->drmcg_props.mem_reclaim_wq[type] = NULL;
+	mutex_unlock(&drmcg_mutex);
+}
+EXPORT_SYMBOL(drmcg_unregister_device_mm);
+
 /**
  * drmcg_try_chg_bo_alloc - charge GEM buffer usage for a device and cgroup
  * @drmcg: the DRM cgroup to be charged to
@@ -1013,6 +1036,13 @@ void drmcg_mem_track_move(struct ttm_buffer_object *old_bo, bool evict,
 
 		ddr->mem_bw_stats[DRMCG_MEM_BW_ATTR_BYTE_CREDIT]
 			-= move_in_bytes;
+
+		if (dev->drmcg_props.mem_reclaim_wq[new_mem_type]
+			!= NULL &&
+			ddr->mem_stats[new_mem_type] >
+				ddr->mem_highs[new_mem_type])
+			schedule_work(dev->
+				drmcg_props.mem_reclaim_wq[new_mem_type]);
 	}
 	mutex_unlock(&dev->drmcg_mutex);
 }
-- 
2.22.0

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