1 files changed, 314 insertions, 0 deletions
diff --git a/drivers/gpu/drm/msm/msm_gem_shrinker.c b/drivers/gpu/drm/msm/msm_gem_shrinker.c
new file mode 100644
index 000000000000..1039e3c0a47b
--- /dev/null
+++ b/drivers/gpu/drm/msm/msm_gem_shrinker.c
@@ -0,0 +1,314 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2016 Red Hat
+ * Author: Rob Clark <robdclark@gmail.com>
+ */
+
+#include <linux/vmalloc.h>
+#include <linux/sched/mm.h>
+
+#include "msm_drv.h"
+#include "msm_gem.h"
+#include "msm_gpu.h"
+#include "msm_gpu_trace.h"
+
+/* Default disabled for now until it has some more testing on the different
+ * iommu combinations that can be paired with the driver:
+ */
+static bool enable_eviction = true;
+MODULE_PARM_DESC(enable_eviction, "Enable swappable GEM buffers");
+module_param(enable_eviction, bool, 0600);
+
+static bool can_swap(void)
+{
+	return enable_eviction && get_nr_swap_pages() > 0;
+}
+
+static bool can_block(struct shrink_control *sc)
+{
+	if (!(sc->gfp_mask & __GFP_DIRECT_RECLAIM))
+		return false;
+	return current_is_kswapd() || (sc->gfp_mask & __GFP_RECLAIM);
+}
+
+static unsigned long
+msm_gem_shrinker_count(struct shrinker *shrinker, struct shrink_control *sc)
+{
+	struct msm_drm_private *priv = shrinker->private_data;
+	unsigned count = priv->lru.dontneed.count;
+
+	if (can_swap())
+		count += priv->lru.willneed.count;
+
+	return count;
+}
+
+static bool
+with_vm_locks(struct ww_acquire_ctx *ticket,
+	      void (*fn)(struct drm_gem_object *obj),
+	      struct drm_gem_object *obj)
+{
+	/*
+	 * Track last locked entry for for unwinding locks in error and
+	 * success paths
+	 */
+	struct drm_gpuvm_bo *vm_bo, *last_locked = NULL;
+	int ret = 0;
+
+	drm_gem_for_each_gpuvm_bo (vm_bo, obj) {
+		struct dma_resv *resv = drm_gpuvm_resv(vm_bo->vm);
+
+		if (resv == obj->resv)
+			continue;
+
+		ret = dma_resv_lock(resv, ticket);
+
+		/*
+		 * Since we already skip the case when the VM and obj
+		 * share a resv (ie. _NO_SHARE objs), we don't expect
+		 * to hit a double-locking scenario... which the lock
+		 * unwinding cannot really cope with.
+		 */
+		WARN_ON(ret == -EALREADY);
+
+		/*
+		 * Don't bother with slow-lock / backoff / retry sequence,
+		 * if we can't get the lock just give up and move on to
+		 * the next object.
+		 */
+		if (ret)
+			goto out_unlock;
+
+		/*
+		 * Hold a ref to prevent the vm_bo from being freed
+		 * and removed from the obj's gpuva list, as that would
+		 * would result in missing the unlock below
+		 */
+		drm_gpuvm_bo_get(vm_bo);
+
+		last_locked = vm_bo;
+	}
+
+	fn(obj);
+
+out_unlock:
+	if (last_locked) {
+		drm_gem_for_each_gpuvm_bo (vm_bo, obj) {
+			struct dma_resv *resv = drm_gpuvm_resv(vm_bo->vm);
+
+			if (resv == obj->resv)
+				continue;
+
+			dma_resv_unlock(resv);
+
+			/* Drop the ref taken while locking: */
+			drm_gpuvm_bo_put(vm_bo);
+
+			if (last_locked == vm_bo)
+				break;
+		}
+	}
+
+	return ret == 0;
+}
+
+static bool
+purge(struct drm_gem_object *obj, struct ww_acquire_ctx *ticket)
+{
+	if (!is_purgeable(to_msm_bo(obj)))
+		return false;
+
+	if (msm_gem_active(obj))
+		return false;
+
+	return with_vm_locks(ticket, msm_gem_purge, obj);
+}
+
+static bool
+evict(struct drm_gem_object *obj, struct ww_acquire_ctx *ticket)
+{
+	if (is_unevictable(to_msm_bo(obj)))
+		return false;
+
+	if (msm_gem_active(obj))
+		return false;
+
+	return with_vm_locks(ticket, msm_gem_evict, obj);
+}
+
+static bool
+wait_for_idle(struct drm_gem_object *obj)
+{
+	enum dma_resv_usage usage = DMA_RESV_USAGE_BOOKKEEP;
+	return dma_resv_wait_timeout(obj->resv, usage, false, 10) > 0;
+}
+
+static bool
+active_purge(struct drm_gem_object *obj, struct ww_acquire_ctx *ticket)
+{
+	if (!wait_for_idle(obj))
+		return false;
+
+	return purge(obj, ticket);
+}
+
+static bool
+active_evict(struct drm_gem_object *obj, struct ww_acquire_ctx *ticket)
+{
+	if (!wait_for_idle(obj))
+		return false;
+
+	return evict(obj, ticket);
+}
+
+static unsigned long
+msm_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc)
+{
+	struct msm_drm_private *priv = shrinker->private_data;
+	struct ww_acquire_ctx ticket;
+	struct {
+		struct drm_gem_lru *lru;
+		bool (*shrink)(struct drm_gem_object *obj, struct ww_acquire_ctx *ticket);
+		bool cond;
+		unsigned long freed;
+		unsigned long remaining;
+	} stages[] = {
+		/* Stages of progressively more aggressive/expensive reclaim: */
+		{ &priv->lru.dontneed, purge,        true },
+		{ &priv->lru.willneed, evict,        can_swap() },
+		{ &priv->lru.dontneed, active_purge, can_block(sc) },
+		{ &priv->lru.willneed, active_evict, can_swap() && can_block(sc) },
+	};
+	long nr = sc->nr_to_scan;
+	unsigned long freed = 0;
+	unsigned long remaining = 0;
+
+	for (unsigned i = 0; (nr > 0) && (i < ARRAY_SIZE(stages)); i++) {
+		if (!stages[i].cond)
+			continue;
+		stages[i].freed =
+			drm_gem_lru_scan(stages[i].lru, nr,
+					 &stages[i].remaining,
+					 stages[i].shrink,
+					 &ticket);
+		nr -= stages[i].freed;
+		freed += stages[i].freed;
+		remaining += stages[i].remaining;
+	}
+
+	if (freed) {
+		trace_msm_gem_shrink(sc->nr_to_scan, stages[0].freed,
+				     stages[1].freed, stages[2].freed,
+				     stages[3].freed);
+	}
+
+	return (freed > 0 && remaining > 0) ? freed : SHRINK_STOP;
+}
+
+#ifdef CONFIG_DEBUG_FS
+unsigned long
+msm_gem_shrinker_shrink(struct drm_device *dev, unsigned long nr_to_scan)
+{
+	struct msm_drm_private *priv = dev->dev_private;
+	struct shrink_control sc = {
+		.nr_to_scan = nr_to_scan,
+	};
+	unsigned long ret = SHRINK_STOP;
+
+	fs_reclaim_acquire(GFP_KERNEL);
+	if (priv->shrinker)
+		ret = msm_gem_shrinker_scan(priv->shrinker, &sc);
+	fs_reclaim_release(GFP_KERNEL);
+
+	return ret;
+}
+#endif
+
+/* since we don't know any better, lets bail after a few
+ * and if necessary the shrinker will be invoked again.
+ * Seems better than unmapping *everything*
+ */
+static const int vmap_shrink_limit = 15;
+
+static bool
+vmap_shrink(struct drm_gem_object *obj, struct ww_acquire_ctx *ticket)
+{
+	if (!is_vunmapable(to_msm_bo(obj)))
+		return false;
+
+	msm_gem_vunmap(obj);
+
+	return true;
+}
+
+static int
+msm_gem_shrinker_vmap(struct notifier_block *nb, unsigned long event, void *ptr)
+{
+	struct msm_drm_private *priv =
+		container_of(nb, struct msm_drm_private, vmap_notifier);
+	struct drm_gem_lru *lrus[] = {
+		&priv->lru.dontneed,
+		&priv->lru.willneed,
+		&priv->lru.pinned,
+		NULL,
+	};
+	unsigned idx, unmapped = 0;
+	unsigned long remaining = 0;
+
+	for (idx = 0; lrus[idx] && unmapped < vmap_shrink_limit; idx++) {
+		unmapped += drm_gem_lru_scan(lrus[idx],
+					     vmap_shrink_limit - unmapped,
+					     &remaining,
+					     vmap_shrink,
+					     NULL);
+	}
+
+	*(unsigned long *)ptr += unmapped;
+
+	if (unmapped > 0)
+		trace_msm_gem_purge_vmaps(unmapped);
+
+	return NOTIFY_DONE;
+}
+
+/**
+ * msm_gem_shrinker_init - Initialize msm shrinker
+ * @dev: drm device
+ *
+ * This function registers and sets up the msm shrinker.
+ */
+int msm_gem_shrinker_init(struct drm_device *dev)
+{
+	struct msm_drm_private *priv = dev->dev_private;
+
+	priv->shrinker = shrinker_alloc(0, "drm-msm_gem");
+	if (!priv->shrinker)
+		return -ENOMEM;
+
+	priv->shrinker->count_objects = msm_gem_shrinker_count;
+	priv->shrinker->scan_objects = msm_gem_shrinker_scan;
+	priv->shrinker->private_data = priv;
+
+	shrinker_register(priv->shrinker);
+
+	priv->vmap_notifier.notifier_call = msm_gem_shrinker_vmap;
+	WARN_ON(register_vmap_purge_notifier(&priv->vmap_notifier));
+
+	return 0;
+}
+
+/**
+ * msm_gem_shrinker_cleanup - Clean up msm shrinker
+ * @dev: drm device
+ *
+ * This function unregisters the msm shrinker.
+ */
+void msm_gem_shrinker_cleanup(struct drm_device *dev)
+{
+	struct msm_drm_private *priv = dev->dev_private;
+
+	if (priv->shrinker) {
+		WARN_ON(unregister_vmap_purge_notifier(&priv->vmap_notifier));
+		shrinker_free(priv->shrinker);
+	}
+}