Sometimes we have to be very careful not to allocate underneath a mutex (or spinlock) and yet still want to track activity. Enter i915_active_acquire_for_context(). This raises the activity counter on i915_active prior to use and ensures that the fence-tree contains a slot for the context.
Signed-off-by: Chris Wilson <[email protected]> --- .../gpu/drm/i915/gem/i915_gem_execbuffer.c | 2 +- drivers/gpu/drm/i915/gt/intel_timeline.c | 4 +- drivers/gpu/drm/i915/i915_active.c | 113 +++++++++++++++--- drivers/gpu/drm/i915/i915_active.h | 14 ++- 4 files changed, 113 insertions(+), 20 deletions(-) diff --git a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c index 18e9325dd98a..a027a0557d3a 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c @@ -1782,7 +1782,7 @@ __parser_mark_active(struct i915_vma *vma, { struct intel_gt_buffer_pool_node *node = vma->private; - return i915_active_ref(&node->active, tl, fence); + return i915_active_ref(&node->active, tl->fence_context, fence); } static int diff --git a/drivers/gpu/drm/i915/gt/intel_timeline.c b/drivers/gpu/drm/i915/gt/intel_timeline.c index 4546284fede1..e4a5326633b8 100644 --- a/drivers/gpu/drm/i915/gt/intel_timeline.c +++ b/drivers/gpu/drm/i915/gt/intel_timeline.c @@ -479,7 +479,9 @@ __intel_timeline_get_seqno(struct intel_timeline *tl, * free it after the current request is retired, which ensures that * all writes into the cacheline from previous requests are complete. */ - err = i915_active_ref(&tl->hwsp_cacheline->active, tl, &rq->fence); + err = i915_active_ref(&tl->hwsp_cacheline->active, + tl->fence_context, + &rq->fence); if (err) goto err_cacheline; diff --git a/drivers/gpu/drm/i915/i915_active.c b/drivers/gpu/drm/i915/i915_active.c index d960d0be5bd2..3f595446fd44 100644 --- a/drivers/gpu/drm/i915/i915_active.c +++ b/drivers/gpu/drm/i915/i915_active.c @@ -217,11 +217,10 @@ excl_retire(struct dma_fence *fence, struct dma_fence_cb *cb) } static struct i915_active_fence * -active_instance(struct i915_active *ref, struct intel_timeline *tl) +active_instance(struct i915_active *ref, u64 idx) { struct active_node *node, *prealloc; struct rb_node **p, *parent; - u64 idx = tl->fence_context; /* * We track the most recently used timeline to skip a rbtree search @@ -353,21 +352,17 @@ __active_del_barrier(struct i915_active *ref, struct active_node *node) return ____active_del_barrier(ref, node, barrier_to_engine(node)); } -int i915_active_ref(struct i915_active *ref, - struct intel_timeline *tl, - struct dma_fence *fence) +int i915_active_ref(struct i915_active *ref, u64 idx, struct dma_fence *fence) { struct i915_active_fence *active; int err; - lockdep_assert_held(&tl->mutex); - /* Prevent reaping in case we malloc/wait while building the tree */ err = i915_active_acquire(ref); if (err) return err; - active = active_instance(ref, tl); + active = active_instance(ref, idx); if (!active) { err = -ENOMEM; goto out; @@ -384,32 +379,104 @@ int i915_active_ref(struct i915_active *ref, atomic_dec(&ref->count); } if (!__i915_active_fence_set(active, fence)) - atomic_inc(&ref->count); + __i915_active_acquire(ref); out: i915_active_release(ref); return err; } -struct dma_fence * -i915_active_set_exclusive(struct i915_active *ref, struct dma_fence *f) +static struct dma_fence * +__i915_active_set_fence(struct i915_active *ref, + struct i915_active_fence *active, + struct dma_fence *fence) { struct dma_fence *prev; /* We expect the caller to manage the exclusive timeline ordering */ GEM_BUG_ON(i915_active_is_idle(ref)); + if (is_barrier(active)) { /* proto-node used by our idle barrier */ + /* + * This request is on the kernel_context timeline, and so + * we can use it to substitute for the pending idle-barrer + * request that we want to emit on the kernel_context. + */ + __active_del_barrier(ref, node_from_active(active)); + RCU_INIT_POINTER(active->fence, NULL); + atomic_dec(&ref->count); + } + rcu_read_lock(); - prev = __i915_active_fence_set(&ref->excl, f); + prev = __i915_active_fence_set(active, fence); if (prev) prev = dma_fence_get_rcu(prev); else - atomic_inc(&ref->count); + __i915_active_acquire(ref); rcu_read_unlock(); return prev; } +static struct i915_active_fence * +__active_lookup(struct i915_active *ref, u64 idx) +{ + struct active_node *node; + struct rb_node *p; + + /* Like active_instance() but with no malloc */ + + node = READ_ONCE(ref->cache); + if (node && node->timeline == idx) + return &node->base; + + spin_lock_irq(&ref->tree_lock); + GEM_BUG_ON(i915_active_is_idle(ref)); + + p = ref->tree.rb_node; + while (p) { + node = rb_entry(p, struct active_node, node); + if (node->timeline == idx) { + ref->cache = node; + spin_unlock_irq(&ref->tree_lock); + return &node->base; + } + + if (node->timeline < idx) + p = p->rb_right; + else + p = p->rb_left; + } + + spin_unlock_irq(&ref->tree_lock); + + return NULL; +} + +struct dma_fence * +__i915_active_ref(struct i915_active *ref, u64 idx, struct dma_fence *fence) +{ + struct dma_fence *prev = ERR_PTR(-ENOENT); + struct i915_active_fence *active; + + if (!i915_active_acquire_if_busy(ref)) + return ERR_PTR(-EINVAL); + + active = __active_lookup(ref, idx); + if (active) + prev = __i915_active_set_fence(ref, active, fence); + + i915_active_release(ref); + return prev; +} + +struct dma_fence * +i915_active_set_exclusive(struct i915_active *ref, struct dma_fence *f) +{ + /* We expect the caller to manage the exclusive timeline ordering */ + return __i915_active_set_fence(ref, &ref->excl, f); +} + bool i915_active_acquire_if_busy(struct i915_active *ref) { debug_active_assert(ref); @@ -443,6 +510,24 @@ int i915_active_acquire(struct i915_active *ref) return err; } +int i915_active_acquire_for_context(struct i915_active *ref, u64 idx) +{ + struct i915_active_fence *active; + int err; + + err = i915_active_acquire(ref); + if (err) + return err; + + active = active_instance(ref, idx); + if (!active) { + i915_active_release(ref); + return -ENOMEM; + } + + return 0; /* return with active ref */ +} + void i915_active_release(struct i915_active *ref) { debug_active_assert(ref); @@ -804,7 +889,7 @@ int i915_active_acquire_preallocate_barrier(struct i915_active *ref, */ RCU_INIT_POINTER(node->base.fence, ERR_PTR(-EAGAIN)); node->base.cb.node.prev = (void *)engine; - atomic_inc(&ref->count); + __i915_active_acquire(ref); } GEM_BUG_ON(rcu_access_pointer(node->base.fence) != ERR_PTR(-EAGAIN)); diff --git a/drivers/gpu/drm/i915/i915_active.h b/drivers/gpu/drm/i915/i915_active.h index cf4058150966..2e0bcb3289ec 100644 --- a/drivers/gpu/drm/i915/i915_active.h +++ b/drivers/gpu/drm/i915/i915_active.h @@ -163,14 +163,18 @@ void __i915_active_init(struct i915_active *ref, __i915_active_init(ref, active, retire, &__mkey, &__wkey); \ } while (0) -int i915_active_ref(struct i915_active *ref, - struct intel_timeline *tl, - struct dma_fence *fence); +struct dma_fence * +__i915_active_ref(struct i915_active *ref, u64 idx, struct dma_fence *fence); +int i915_active_ref(struct i915_active *ref, u64 idx, struct dma_fence *fence); static inline int i915_active_add_request(struct i915_active *ref, struct i915_request *rq) { - return i915_active_ref(ref, i915_request_timeline(rq), &rq->fence); + struct intel_timeline *tl = i915_request_timeline(rq); + + lockdep_assert_held(&tl->mutex); + + return i915_active_ref(ref, tl->fence_context, &rq->fence); } struct dma_fence * @@ -198,7 +202,9 @@ int i915_request_await_active(struct i915_request *rq, #define I915_ACTIVE_AWAIT_BARRIER BIT(2) int i915_active_acquire(struct i915_active *ref); +int i915_active_acquire_for_context(struct i915_active *ref, u64 idx); bool i915_active_acquire_if_busy(struct i915_active *ref); + void i915_active_release(struct i915_active *ref); static inline void __i915_active_acquire(struct i915_active *ref) -- 2.20.1 _______________________________________________ Intel-gfx mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/intel-gfx
