[Intel-gfx] [PATCH 28/61] drm/i915: Defer pin calls in buffer pool until first use by caller.

Maarten Lankhorst
2020-10-02T13:00:19Z

We need to take the obj lock to pin pages, so wait until the callers
have done so, before making the object unshrinkable.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
---
.../gpu/drm/i915/gem/i915_gem_execbuffer.c | 2 +
.../gpu/drm/i915/gem/i915_gem_object_blt.c | 6 +++
.../gpu/drm/i915/gt/intel_gt_buffer_pool.c | 47 +++++++++----------
.../gpu/drm/i915/gt/intel_gt_buffer_pool.h | 5 ++
.../drm/i915/gt/intel_gt_buffer_pool_types.h | 1 +
5 files changed, 35 insertions(+), 26 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
index 46ef71196f7d..7ef52c876cb8 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
@@ -1338,6 +1338,7 @@ static int __reloc_gpu_alloc(struct i915_execbuffer *eb,
err = PTR_ERR(cmd);
goto err_pool;
}
+ intel_gt_buffer_pool_mark_used(pool);

batch = i915_vma_instance(pool->obj, vma->vm, NULL);
if (IS_ERR(batch)) {
@@ -2625,6 +2626,7 @@ static int eb_parse(struct i915_execbuffer *eb)
err = PTR_ERR(shadow);
goto err;
}
+ intel_gt_buffer_pool_mark_used(pool);
i915_gem_object_set_readonly(shadow->obj);
shadow->private = pool;

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object_blt.c b/drivers/gpu/drm/i915/gem/i915_gem_object_blt.c
index aee7ad3cc3c6..e0b873c3f46a 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_object_blt.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_object_blt.c
@@ -54,6 +54,9 @@ struct i915_vma *intel_emit_vma_fill_blt(struct intel_context *ce,
if (unlikely(err))
goto out_put;

+ /* we pinned the pool, mark it as such */
+ intel_gt_buffer_pool_mark_used(pool);
+
cmd = i915_gem_object_pin_map(pool->obj, I915_MAP_WC);
if (IS_ERR(cmd)) {
err = PTR_ERR(cmd);
@@ -276,6 +279,9 @@ struct i915_vma *intel_emit_vma_copy_blt(struct intel_context *ce,
if (unlikely(err))
goto out_put;

+ /* we pinned the pool, mark it as such */
+ intel_gt_buffer_pool_mark_used(pool);
+
cmd = i915_gem_object_pin_map(pool->obj, I915_MAP_WC);
if (IS_ERR(cmd)) {
err = PTR_ERR(cmd);
diff --git a/drivers/gpu/drm/i915/gt/intel_gt_buffer_pool.c b/drivers/gpu/drm/i915/gt/intel_gt_buffer_pool.c
index 104cb30e8c13..030759305196 100644
--- a/drivers/gpu/drm/i915/gt/intel_gt_buffer_pool.c
+++ b/drivers/gpu/drm/i915/gt/intel_gt_buffer_pool.c
@@ -98,28 +98,6 @@ static void pool_free_work(struct work_struct *wrk)
round_jiffies_up_relative(HZ));
}

-static int pool_active(struct i915_active *ref)
-{
- struct intel_gt_buffer_pool_node *node =
- container_of(ref, typeof(*node), active);
- struct dma_resv *resv = node->obj->base.resv;
- int err;
-
- if (dma_resv_trylock(resv)) {
- dma_resv_add_excl_fence(resv, NULL);
- dma_resv_unlock(resv);
- }
-
- err = i915_gem_object_pin_pages(node->obj);
- if (err)
- return err;
-
- /* Hide this pinned object from the shrinker until retired */
- i915_gem_object_make_unshrinkable(node->obj);
-
- return 0;
-}
-
__i915_active_call
static void pool_retire(struct i915_active *ref)
{
@@ -129,10 +107,13 @@ static void pool_retire(struct i915_active *ref)
struct list_head *list = bucket_for_size(pool, node->obj->base.size);
unsigned long flags;

- i915_gem_object_unpin_pages(node->obj);
+ if (node->pinned) {
+ i915_gem_object_unpin_pages(node->obj);

- /* Return this object to the shrinker pool */
- i915_gem_object_make_purgeable(node->obj);
+ /* Return this object to the shrinker pool */
+ i915_gem_object_make_purgeable(node->obj);
+ node->pinned = false;
+ }

GEM_BUG_ON(node->age);
spin_lock_irqsave(&pool->lock, flags);
@@ -144,6 +125,19 @@ static void pool_retire(struct i915_active *ref)
round_jiffies_up_relative(HZ));
}

+void intel_gt_buffer_pool_mark_used(struct intel_gt_buffer_pool_node *node)
+{
+ assert_object_held(node->obj);
+
+ if (node->pinned)
+ return;
+
+ __i915_gem_object_pin_pages(node->obj);
+ /* Hide this pinned object from the shrinker until retired */
+ i915_gem_object_make_unshrinkable(node->obj);
+ node->pinned = true;
+}
+
static struct intel_gt_buffer_pool_node *
node_create(struct intel_gt_buffer_pool *pool, size_t sz)
{
@@ -158,7 +152,8 @@ node_create(struct intel_gt_buffer_pool *pool, size_t sz)

node->age = 0;
node->pool = pool;
- i915_active_init(&node->active, pool_active, pool_retire);
+ node->pinned = false;
+ i915_active_init(&node->active, NULL, pool_retire);

obj = i915_gem_object_create_internal(gt->i915, sz);
if (IS_ERR(obj)) {
diff --git a/drivers/gpu/drm/i915/gt/intel_gt_buffer_pool.h b/drivers/gpu/drm/i915/gt/intel_gt_buffer_pool.h
index 42cbac003e8a..9878ce9a07ab 100644
--- a/drivers/gpu/drm/i915/gt/intel_gt_buffer_pool.h
+++ b/drivers/gpu/drm/i915/gt/intel_gt_buffer_pool.h
@@ -17,10 +17,15 @@ struct i915_request;
struct intel_gt_buffer_pool_node *
intel_gt_get_buffer_pool(struct intel_gt *gt, size_t size);

+void intel_gt_buffer_pool_mark_used(struct intel_gt_buffer_pool_node *node);
+
static inline int
intel_gt_buffer_pool_mark_active(struct intel_gt_buffer_pool_node *node,
struct i915_request *rq)
{
+ /* did we call mark_used? */
+ GEM_WARN_ON(!node->pinned);
+
return i915_active_add_request(&node->active, rq);
}

diff --git a/drivers/gpu/drm/i915/gt/intel_gt_buffer_pool_types.h b/drivers/gpu/drm/i915/gt/intel_gt_buffer_pool_types.h
index bcf1658c9633..0401825e829d 100644
--- a/drivers/gpu/drm/i915/gt/intel_gt_buffer_pool_types.h
+++ b/drivers/gpu/drm/i915/gt/intel_gt_buffer_pool_types.h
@@ -31,6 +31,7 @@ struct intel_gt_buffer_pool_node {
struct rcu_head rcu;
};
unsigned long age;
+ bool pinned;
};

#endif /* INTEL_GT_BUFFER_POOL_TYPES_H */