[Intel-gfx] [PATCH 06/20] drm/i915/gem: Remove the call for no-evict i915_vma_pin

From: Chris Wilson <chris@chris-wilson.co.uk>
To: intel-gfx@lists.freedesktop.org
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Subject: [Intel-gfx] [PATCH 06/20] drm/i915/gem: Remove the call for no-evict i915_vma_pin
Date: Mon,  6 Jul 2020 07:19:12 +0100	[thread overview]
Message-ID: <20200706061926.6687-7-chris@chris-wilson.co.uk> (raw)
In-Reply-To: <20200706061926.6687-1-chris@chris-wilson.co.uk>

Remove the stub i915_vma_pin() used for incrementally pining objects for
execbuf (under the severe restriction that they must not wait on a
resource as we may have already pinned it) and replace it with a
i915_vma_pin_inplace() that is only allowed to reclaim the currently
bound location for the vma (and will never wait for a pinned resource).

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
---
 .../gpu/drm/i915/gem/i915_gem_execbuffer.c    | 69 +++++++++++--------
 drivers/gpu/drm/i915/i915_vma.c               |  6 +-
 drivers/gpu/drm/i915/i915_vma.h               |  2 +
 3 files changed, 45 insertions(+), 32 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
index 35a57c1fc9c3..1015c4fd9f3e 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
@@ -452,49 +452,55 @@ static u64 eb_pin_flags(const struct drm_i915_gem_exec_object2 *entry,
 	return pin_flags;
 }
 
+static bool eb_pin_vma_fence_inplace(struct eb_vma *ev)
+{
+	struct i915_vma *vma = ev->vma;
+	struct i915_fence_reg *reg = vma->fence;
+
+	if (reg) {
+		if (READ_ONCE(reg->dirty))
+			return false;
+
+		atomic_inc(&reg->pin_count);
+		ev->flags |= __EXEC_OBJECT_HAS_FENCE;
+	} else {
+		if (i915_gem_object_is_tiled(vma->obj))
+			return false;
+	}
+
+	return true;
+}
+
 static inline bool
-eb_pin_vma(struct i915_execbuffer *eb,
-	   const struct drm_i915_gem_exec_object2 *entry,
-	   struct eb_vma *ev)
+eb_pin_vma_inplace(struct i915_execbuffer *eb,
+		   const struct drm_i915_gem_exec_object2 *entry,
+		   struct eb_vma *ev)
 {
 	struct i915_vma *vma = ev->vma;
-	u64 pin_flags;
+	unsigned int pin_flags;
 
-	if (vma->node.size)
-		pin_flags = vma->node.start;
-	else
-		pin_flags = entry->offset & PIN_OFFSET_MASK;
+	if (eb_vma_misplaced(entry, vma, ev->flags))
+		return false;
 
-	pin_flags |= PIN_USER | PIN_NOEVICT | PIN_OFFSET_FIXED;
+	pin_flags = PIN_USER;
 	if (unlikely(ev->flags & EXEC_OBJECT_NEEDS_GTT))
 		pin_flags |= PIN_GLOBAL;
 
 	/* Attempt to reuse the current location if available */
-	if (unlikely(i915_vma_pin(vma, 0, 0, pin_flags))) {
-		if (entry->flags & EXEC_OBJECT_PINNED)
-			return false;
-
-		/* Failing that pick any _free_ space if suitable */
-		if (unlikely(i915_vma_pin(vma,
-					  entry->pad_to_size,
-					  entry->alignment,
-					  eb_pin_flags(entry, ev->flags) |
-					  PIN_USER | PIN_NOEVICT)))
-			return false;
-	}
+	if (!i915_vma_pin_inplace(vma, pin_flags))
+		return false;
 
 	if (unlikely(ev->flags & EXEC_OBJECT_NEEDS_FENCE)) {
-		if (unlikely(i915_vma_pin_fence(vma))) {
-			i915_vma_unpin(vma);
+		if (!eb_pin_vma_fence_inplace(ev)) {
+			__i915_vma_unpin(vma);
 			return false;
 		}
-
-		if (vma->fence)
-			ev->flags |= __EXEC_OBJECT_HAS_FENCE;
 	}
 
+	GEM_BUG_ON(eb_vma_misplaced(entry, vma, ev->flags));
+
 	ev->flags |= __EXEC_OBJECT_HAS_PIN;
-	return !eb_vma_misplaced(entry, vma, ev->flags);
+	return true;
 }
 
 static int
@@ -676,14 +682,17 @@ static int eb_reserve_vm(struct i915_execbuffer *eb)
 		struct drm_i915_gem_exec_object2 *entry = ev->exec;
 		struct i915_vma *vma = ev->vma;
 
-		if (eb_pin_vma(eb, entry, ev)) {
+		if (eb_pin_vma_inplace(eb, entry, ev)) {
 			if (entry->offset != vma->node.start) {
 				entry->offset = vma->node.start | UPDATE;
 				eb->args->flags |= __EXEC_HAS_RELOC;
 			}
 		} else {
-			eb_unreserve_vma(ev);
-			list_add_tail(&ev->unbound_link, &unbound);
+			/* Lightly sort user placed objects to the fore */
+			if (ev->flags & EXEC_OBJECT_PINNED)
+				list_add(&ev->unbound_link, &unbound);
+			else
+				list_add_tail(&ev->unbound_link, &unbound);
 		}
 	}
 
diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c
index 3b43d485d7c2..0c9af30fc3d6 100644
--- a/drivers/gpu/drm/i915/i915_vma.c
+++ b/drivers/gpu/drm/i915/i915_vma.c
@@ -740,11 +740,13 @@ i915_vma_detach(struct i915_vma *vma)
 	list_del(&vma->vm_link);
 }
 
-static bool try_qad_pin(struct i915_vma *vma, unsigned int flags)
+bool i915_vma_pin_inplace(struct i915_vma *vma, unsigned int flags)
 {
 	unsigned int bound;
 	bool pinned = true;
 
+	GEM_BUG_ON(flags & ~I915_VMA_BIND_MASK);
+
 	bound = atomic_read(&vma->flags);
 	do {
 		if (unlikely(flags & ~bound))
@@ -865,7 +867,7 @@ int i915_vma_pin(struct i915_vma *vma, u64 size, u64 alignment, u64 flags)
 	GEM_BUG_ON(!(flags & (PIN_USER | PIN_GLOBAL)));
 
 	/* First try and grab the pin without rebinding the vma */
-	if (try_qad_pin(vma, flags & I915_VMA_BIND_MASK))
+	if (i915_vma_pin_inplace(vma, flags & I915_VMA_BIND_MASK))
 		return 0;
 
 	err = vma_get_pages(vma);
diff --git a/drivers/gpu/drm/i915/i915_vma.h b/drivers/gpu/drm/i915/i915_vma.h
index d0d01f909548..03fea54fd573 100644
--- a/drivers/gpu/drm/i915/i915_vma.h
+++ b/drivers/gpu/drm/i915/i915_vma.h
@@ -236,6 +236,8 @@ static inline void i915_vma_unlock(struct i915_vma *vma)
 	dma_resv_unlock(vma->resv);
 }
 
+bool i915_vma_pin_inplace(struct i915_vma *vma, unsigned int flags);
+
 int __must_check
 i915_vma_pin(struct i915_vma *vma, u64 size, u64 alignment, u64 flags);
 int i915_ggtt_pin(struct i915_vma *vma, u32 align, unsigned int flags);
-- 
2.20.1

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