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3b0a05792e
Allow the caller to also wait upon the barriers stored in i915_active. v2: Hook up i915_request_await_active(I915_ACTIVE_AWAIT_BARRIER) as well for completeness, and avoid the lazy GEM_BUG_ON()! v3: Pull flush_lazy_signals() under the active-ref protection as it too walks the rbtree and so we must be careful that we do not free it as we iterate. Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200406155840.1728-2-chris@chris-wilson.co.uk
1077 lines
26 KiB
C
1077 lines
26 KiB
C
/*
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* SPDX-License-Identifier: MIT
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*
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* Copyright © 2019 Intel Corporation
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*/
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#include <linux/debugobjects.h>
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#include "gt/intel_context.h"
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#include "gt/intel_engine_heartbeat.h"
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#include "gt/intel_engine_pm.h"
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#include "gt/intel_ring.h"
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#include "i915_drv.h"
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#include "i915_active.h"
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#include "i915_globals.h"
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/*
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* Active refs memory management
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*
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* To be more economical with memory, we reap all the i915_active trees as
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* they idle (when we know the active requests are inactive) and allocate the
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* nodes from a local slab cache to hopefully reduce the fragmentation.
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*/
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static struct i915_global_active {
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struct i915_global base;
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struct kmem_cache *slab_cache;
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} global;
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struct active_node {
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struct i915_active_fence base;
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struct i915_active *ref;
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struct rb_node node;
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u64 timeline;
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};
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static inline struct active_node *
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node_from_active(struct i915_active_fence *active)
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{
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return container_of(active, struct active_node, base);
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}
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#define take_preallocated_barriers(x) llist_del_all(&(x)->preallocated_barriers)
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static inline bool is_barrier(const struct i915_active_fence *active)
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{
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return IS_ERR(rcu_access_pointer(active->fence));
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}
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static inline struct llist_node *barrier_to_ll(struct active_node *node)
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{
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GEM_BUG_ON(!is_barrier(&node->base));
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return (struct llist_node *)&node->base.cb.node;
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}
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static inline struct intel_engine_cs *
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__barrier_to_engine(struct active_node *node)
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{
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return (struct intel_engine_cs *)READ_ONCE(node->base.cb.node.prev);
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}
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static inline struct intel_engine_cs *
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barrier_to_engine(struct active_node *node)
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{
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GEM_BUG_ON(!is_barrier(&node->base));
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return __barrier_to_engine(node);
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}
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static inline struct active_node *barrier_from_ll(struct llist_node *x)
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{
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return container_of((struct list_head *)x,
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struct active_node, base.cb.node);
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}
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#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM) && IS_ENABLED(CONFIG_DEBUG_OBJECTS)
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static void *active_debug_hint(void *addr)
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{
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struct i915_active *ref = addr;
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return (void *)ref->active ?: (void *)ref->retire ?: (void *)ref;
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}
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static struct debug_obj_descr active_debug_desc = {
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.name = "i915_active",
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.debug_hint = active_debug_hint,
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};
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static void debug_active_init(struct i915_active *ref)
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{
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debug_object_init(ref, &active_debug_desc);
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}
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static void debug_active_activate(struct i915_active *ref)
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{
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lockdep_assert_held(&ref->tree_lock);
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if (!atomic_read(&ref->count)) /* before the first inc */
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debug_object_activate(ref, &active_debug_desc);
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}
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static void debug_active_deactivate(struct i915_active *ref)
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{
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lockdep_assert_held(&ref->tree_lock);
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if (!atomic_read(&ref->count)) /* after the last dec */
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debug_object_deactivate(ref, &active_debug_desc);
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}
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static void debug_active_fini(struct i915_active *ref)
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{
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debug_object_free(ref, &active_debug_desc);
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}
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static void debug_active_assert(struct i915_active *ref)
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{
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debug_object_assert_init(ref, &active_debug_desc);
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}
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#else
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static inline void debug_active_init(struct i915_active *ref) { }
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static inline void debug_active_activate(struct i915_active *ref) { }
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static inline void debug_active_deactivate(struct i915_active *ref) { }
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static inline void debug_active_fini(struct i915_active *ref) { }
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static inline void debug_active_assert(struct i915_active *ref) { }
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#endif
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static void
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__active_retire(struct i915_active *ref)
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{
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struct active_node *it, *n;
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struct rb_root root;
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unsigned long flags;
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GEM_BUG_ON(i915_active_is_idle(ref));
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/* return the unused nodes to our slabcache -- flushing the allocator */
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if (!atomic_dec_and_lock_irqsave(&ref->count, &ref->tree_lock, flags))
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return;
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GEM_BUG_ON(rcu_access_pointer(ref->excl.fence));
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debug_active_deactivate(ref);
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root = ref->tree;
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ref->tree = RB_ROOT;
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ref->cache = NULL;
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spin_unlock_irqrestore(&ref->tree_lock, flags);
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/* After the final retire, the entire struct may be freed */
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if (ref->retire)
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ref->retire(ref);
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/* ... except if you wait on it, you must manage your own references! */
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wake_up_var(ref);
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rbtree_postorder_for_each_entry_safe(it, n, &root, node) {
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GEM_BUG_ON(i915_active_fence_isset(&it->base));
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kmem_cache_free(global.slab_cache, it);
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}
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}
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static void
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active_work(struct work_struct *wrk)
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{
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struct i915_active *ref = container_of(wrk, typeof(*ref), work);
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GEM_BUG_ON(!atomic_read(&ref->count));
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if (atomic_add_unless(&ref->count, -1, 1))
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return;
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__active_retire(ref);
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}
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static void
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active_retire(struct i915_active *ref)
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{
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GEM_BUG_ON(!atomic_read(&ref->count));
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if (atomic_add_unless(&ref->count, -1, 1))
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return;
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if (ref->flags & I915_ACTIVE_RETIRE_SLEEPS) {
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queue_work(system_unbound_wq, &ref->work);
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return;
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}
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__active_retire(ref);
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}
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static inline struct dma_fence **
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__active_fence_slot(struct i915_active_fence *active)
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{
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return (struct dma_fence ** __force)&active->fence;
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}
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static inline bool
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active_fence_cb(struct dma_fence *fence, struct dma_fence_cb *cb)
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{
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struct i915_active_fence *active =
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container_of(cb, typeof(*active), cb);
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return cmpxchg(__active_fence_slot(active), fence, NULL) == fence;
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}
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static void
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node_retire(struct dma_fence *fence, struct dma_fence_cb *cb)
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{
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if (active_fence_cb(fence, cb))
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active_retire(container_of(cb, struct active_node, base.cb)->ref);
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}
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static void
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excl_retire(struct dma_fence *fence, struct dma_fence_cb *cb)
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{
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if (active_fence_cb(fence, cb))
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active_retire(container_of(cb, struct i915_active, excl.cb));
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}
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static struct i915_active_fence *
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active_instance(struct i915_active *ref, struct intel_timeline *tl)
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{
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struct active_node *node, *prealloc;
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struct rb_node **p, *parent;
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u64 idx = tl->fence_context;
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/*
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* We track the most recently used timeline to skip a rbtree search
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* for the common case, under typical loads we never need the rbtree
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* at all. We can reuse the last slot if it is empty, that is
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* after the previous activity has been retired, or if it matches the
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* current timeline.
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*/
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node = READ_ONCE(ref->cache);
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if (node && node->timeline == idx)
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return &node->base;
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/* Preallocate a replacement, just in case */
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prealloc = kmem_cache_alloc(global.slab_cache, GFP_KERNEL);
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if (!prealloc)
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return NULL;
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spin_lock_irq(&ref->tree_lock);
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GEM_BUG_ON(i915_active_is_idle(ref));
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parent = NULL;
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p = &ref->tree.rb_node;
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while (*p) {
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parent = *p;
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node = rb_entry(parent, struct active_node, node);
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if (node->timeline == idx) {
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kmem_cache_free(global.slab_cache, prealloc);
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goto out;
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}
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if (node->timeline < idx)
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p = &parent->rb_right;
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else
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p = &parent->rb_left;
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}
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node = prealloc;
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__i915_active_fence_init(&node->base, NULL, node_retire);
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node->ref = ref;
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node->timeline = idx;
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rb_link_node(&node->node, parent, p);
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rb_insert_color(&node->node, &ref->tree);
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out:
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ref->cache = node;
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spin_unlock_irq(&ref->tree_lock);
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BUILD_BUG_ON(offsetof(typeof(*node), base));
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return &node->base;
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}
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void __i915_active_init(struct i915_active *ref,
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int (*active)(struct i915_active *ref),
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void (*retire)(struct i915_active *ref),
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struct lock_class_key *mkey,
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struct lock_class_key *wkey)
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{
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unsigned long bits;
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debug_active_init(ref);
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ref->flags = 0;
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ref->active = active;
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ref->retire = ptr_unpack_bits(retire, &bits, 2);
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if (bits & I915_ACTIVE_MAY_SLEEP)
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ref->flags |= I915_ACTIVE_RETIRE_SLEEPS;
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spin_lock_init(&ref->tree_lock);
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ref->tree = RB_ROOT;
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ref->cache = NULL;
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init_llist_head(&ref->preallocated_barriers);
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atomic_set(&ref->count, 0);
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__mutex_init(&ref->mutex, "i915_active", mkey);
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__i915_active_fence_init(&ref->excl, NULL, excl_retire);
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INIT_WORK(&ref->work, active_work);
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#if IS_ENABLED(CONFIG_LOCKDEP)
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lockdep_init_map(&ref->work.lockdep_map, "i915_active.work", wkey, 0);
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#endif
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}
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static bool ____active_del_barrier(struct i915_active *ref,
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struct active_node *node,
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struct intel_engine_cs *engine)
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{
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struct llist_node *head = NULL, *tail = NULL;
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struct llist_node *pos, *next;
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GEM_BUG_ON(node->timeline != engine->kernel_context->timeline->fence_context);
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/*
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* Rebuild the llist excluding our node. We may perform this
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* outside of the kernel_context timeline mutex and so someone
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* else may be manipulating the engine->barrier_tasks, in
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* which case either we or they will be upset :)
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*
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* A second __active_del_barrier() will report failure to claim
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* the active_node and the caller will just shrug and know not to
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* claim ownership of its node.
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*
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* A concurrent i915_request_add_active_barriers() will miss adding
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* any of the tasks, but we will try again on the next -- and since
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* we are actively using the barrier, we know that there will be
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* at least another opportunity when we idle.
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*/
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llist_for_each_safe(pos, next, llist_del_all(&engine->barrier_tasks)) {
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if (node == barrier_from_ll(pos)) {
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node = NULL;
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continue;
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}
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pos->next = head;
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head = pos;
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if (!tail)
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tail = pos;
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}
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if (head)
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llist_add_batch(head, tail, &engine->barrier_tasks);
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return !node;
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}
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static bool
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__active_del_barrier(struct i915_active *ref, struct active_node *node)
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{
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return ____active_del_barrier(ref, node, barrier_to_engine(node));
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}
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int i915_active_ref(struct i915_active *ref,
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struct intel_timeline *tl,
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struct dma_fence *fence)
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{
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struct i915_active_fence *active;
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int err;
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lockdep_assert_held(&tl->mutex);
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/* Prevent reaping in case we malloc/wait while building the tree */
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err = i915_active_acquire(ref);
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if (err)
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return err;
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active = active_instance(ref, tl);
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if (!active) {
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err = -ENOMEM;
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goto out;
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}
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if (is_barrier(active)) { /* proto-node used by our idle barrier */
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/*
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* This request is on the kernel_context timeline, and so
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* we can use it to substitute for the pending idle-barrer
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* request that we want to emit on the kernel_context.
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*/
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__active_del_barrier(ref, node_from_active(active));
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RCU_INIT_POINTER(active->fence, NULL);
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atomic_dec(&ref->count);
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}
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if (!__i915_active_fence_set(active, fence))
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atomic_inc(&ref->count);
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out:
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i915_active_release(ref);
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return err;
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}
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struct dma_fence *
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i915_active_set_exclusive(struct i915_active *ref, struct dma_fence *f)
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{
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struct dma_fence *prev;
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/* We expect the caller to manage the exclusive timeline ordering */
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GEM_BUG_ON(i915_active_is_idle(ref));
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rcu_read_lock();
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prev = __i915_active_fence_set(&ref->excl, f);
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if (prev)
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prev = dma_fence_get_rcu(prev);
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else
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atomic_inc(&ref->count);
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rcu_read_unlock();
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return prev;
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}
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bool i915_active_acquire_if_busy(struct i915_active *ref)
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{
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debug_active_assert(ref);
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return atomic_add_unless(&ref->count, 1, 0);
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}
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int i915_active_acquire(struct i915_active *ref)
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{
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int err;
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if (i915_active_acquire_if_busy(ref))
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return 0;
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err = mutex_lock_interruptible(&ref->mutex);
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if (err)
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return err;
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if (likely(!i915_active_acquire_if_busy(ref))) {
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if (ref->active)
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err = ref->active(ref);
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if (!err) {
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spin_lock_irq(&ref->tree_lock); /* __active_retire() */
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debug_active_activate(ref);
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atomic_inc(&ref->count);
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spin_unlock_irq(&ref->tree_lock);
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}
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}
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mutex_unlock(&ref->mutex);
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return err;
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}
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void i915_active_release(struct i915_active *ref)
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{
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debug_active_assert(ref);
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active_retire(ref);
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}
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static void enable_signaling(struct i915_active_fence *active)
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{
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struct dma_fence *fence;
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if (unlikely(is_barrier(active)))
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return;
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fence = i915_active_fence_get(active);
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if (!fence)
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return;
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dma_fence_enable_sw_signaling(fence);
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dma_fence_put(fence);
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}
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static int flush_barrier(struct active_node *it)
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{
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struct intel_engine_cs *engine;
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if (likely(!is_barrier(&it->base)))
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return 0;
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engine = __barrier_to_engine(it);
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smp_rmb(); /* serialise with add_active_barriers */
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if (!is_barrier(&it->base))
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return 0;
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return intel_engine_flush_barriers(engine);
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}
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static int flush_lazy_signals(struct i915_active *ref)
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{
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struct active_node *it, *n;
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int err = 0;
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enable_signaling(&ref->excl);
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rbtree_postorder_for_each_entry_safe(it, n, &ref->tree, node) {
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err = flush_barrier(it); /* unconnected idle barrier? */
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if (err)
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break;
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enable_signaling(&it->base);
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}
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return err;
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}
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int __i915_active_wait(struct i915_active *ref, int state)
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{
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int err;
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might_sleep();
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if (!i915_active_acquire_if_busy(ref))
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return 0;
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/* Any fence added after the wait begins will not be auto-signaled */
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err = flush_lazy_signals(ref);
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i915_active_release(ref);
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if (err)
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return err;
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if (!i915_active_is_idle(ref) &&
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___wait_var_event(ref, i915_active_is_idle(ref),
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state, 0, 0, schedule()))
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return -EINTR;
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|
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flush_work(&ref->work);
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return 0;
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}
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|
|
static int __await_active(struct i915_active_fence *active,
|
|
int (*fn)(void *arg, struct dma_fence *fence),
|
|
void *arg)
|
|
{
|
|
struct dma_fence *fence;
|
|
|
|
if (is_barrier(active)) /* XXX flush the barrier? */
|
|
return 0;
|
|
|
|
fence = i915_active_fence_get(active);
|
|
if (fence) {
|
|
int err;
|
|
|
|
err = fn(arg, fence);
|
|
dma_fence_put(fence);
|
|
if (err < 0)
|
|
return err;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
struct wait_barrier {
|
|
struct wait_queue_entry base;
|
|
struct i915_active *ref;
|
|
};
|
|
|
|
static int
|
|
barrier_wake(wait_queue_entry_t *wq, unsigned int mode, int flags, void *key)
|
|
{
|
|
struct wait_barrier *wb = container_of(wq, typeof(*wb), base);
|
|
|
|
if (i915_active_is_idle(wb->ref)) {
|
|
list_del(&wq->entry);
|
|
i915_sw_fence_complete(wq->private);
|
|
kfree(wq);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int __await_barrier(struct i915_active *ref, struct i915_sw_fence *fence)
|
|
{
|
|
struct wait_barrier *wb;
|
|
|
|
wb = kmalloc(sizeof(*wb), GFP_KERNEL);
|
|
if (unlikely(!wb))
|
|
return -ENOMEM;
|
|
|
|
GEM_BUG_ON(i915_active_is_idle(ref));
|
|
if (!i915_sw_fence_await(fence)) {
|
|
kfree(wb);
|
|
return -EINVAL;
|
|
}
|
|
|
|
wb->base.flags = 0;
|
|
wb->base.func = barrier_wake;
|
|
wb->base.private = fence;
|
|
wb->ref = ref;
|
|
|
|
add_wait_queue(__var_waitqueue(ref), &wb->base);
|
|
return 0;
|
|
}
|
|
|
|
static int await_active(struct i915_active *ref,
|
|
unsigned int flags,
|
|
int (*fn)(void *arg, struct dma_fence *fence),
|
|
void *arg, struct i915_sw_fence *barrier)
|
|
{
|
|
int err = 0;
|
|
|
|
if (!i915_active_acquire_if_busy(ref))
|
|
return 0;
|
|
|
|
if (flags & I915_ACTIVE_AWAIT_EXCL &&
|
|
rcu_access_pointer(ref->excl.fence)) {
|
|
err = __await_active(&ref->excl, fn, arg);
|
|
if (err)
|
|
goto out;
|
|
}
|
|
|
|
if (flags & I915_ACTIVE_AWAIT_ACTIVE) {
|
|
struct active_node *it, *n;
|
|
|
|
rbtree_postorder_for_each_entry_safe(it, n, &ref->tree, node) {
|
|
err = __await_active(&it->base, fn, arg);
|
|
if (err)
|
|
goto out;
|
|
}
|
|
}
|
|
|
|
if (flags & I915_ACTIVE_AWAIT_BARRIER) {
|
|
err = flush_lazy_signals(ref);
|
|
if (err)
|
|
goto out;
|
|
|
|
err = __await_barrier(ref, barrier);
|
|
if (err)
|
|
goto out;
|
|
}
|
|
|
|
out:
|
|
i915_active_release(ref);
|
|
return err;
|
|
}
|
|
|
|
static int rq_await_fence(void *arg, struct dma_fence *fence)
|
|
{
|
|
return i915_request_await_dma_fence(arg, fence);
|
|
}
|
|
|
|
int i915_request_await_active(struct i915_request *rq,
|
|
struct i915_active *ref,
|
|
unsigned int flags)
|
|
{
|
|
return await_active(ref, flags, rq_await_fence, rq, &rq->submit);
|
|
}
|
|
|
|
static int sw_await_fence(void *arg, struct dma_fence *fence)
|
|
{
|
|
return i915_sw_fence_await_dma_fence(arg, fence, 0,
|
|
GFP_NOWAIT | __GFP_NOWARN);
|
|
}
|
|
|
|
int i915_sw_fence_await_active(struct i915_sw_fence *fence,
|
|
struct i915_active *ref,
|
|
unsigned int flags)
|
|
{
|
|
return await_active(ref, flags, sw_await_fence, fence, fence);
|
|
}
|
|
|
|
#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM)
|
|
void i915_active_fini(struct i915_active *ref)
|
|
{
|
|
debug_active_fini(ref);
|
|
GEM_BUG_ON(atomic_read(&ref->count));
|
|
GEM_BUG_ON(work_pending(&ref->work));
|
|
GEM_BUG_ON(!RB_EMPTY_ROOT(&ref->tree));
|
|
mutex_destroy(&ref->mutex);
|
|
}
|
|
#endif
|
|
|
|
static inline bool is_idle_barrier(struct active_node *node, u64 idx)
|
|
{
|
|
return node->timeline == idx && !i915_active_fence_isset(&node->base);
|
|
}
|
|
|
|
static struct active_node *reuse_idle_barrier(struct i915_active *ref, u64 idx)
|
|
{
|
|
struct rb_node *prev, *p;
|
|
|
|
if (RB_EMPTY_ROOT(&ref->tree))
|
|
return NULL;
|
|
|
|
spin_lock_irq(&ref->tree_lock);
|
|
GEM_BUG_ON(i915_active_is_idle(ref));
|
|
|
|
/*
|
|
* Try to reuse any existing barrier nodes already allocated for this
|
|
* i915_active, due to overlapping active phases there is likely a
|
|
* node kept alive (as we reuse before parking). We prefer to reuse
|
|
* completely idle barriers (less hassle in manipulating the llists),
|
|
* but otherwise any will do.
|
|
*/
|
|
if (ref->cache && is_idle_barrier(ref->cache, idx)) {
|
|
p = &ref->cache->node;
|
|
goto match;
|
|
}
|
|
|
|
prev = NULL;
|
|
p = ref->tree.rb_node;
|
|
while (p) {
|
|
struct active_node *node =
|
|
rb_entry(p, struct active_node, node);
|
|
|
|
if (is_idle_barrier(node, idx))
|
|
goto match;
|
|
|
|
prev = p;
|
|
if (node->timeline < idx)
|
|
p = p->rb_right;
|
|
else
|
|
p = p->rb_left;
|
|
}
|
|
|
|
/*
|
|
* No quick match, but we did find the leftmost rb_node for the
|
|
* kernel_context. Walk the rb_tree in-order to see if there were
|
|
* any idle-barriers on this timeline that we missed, or just use
|
|
* the first pending barrier.
|
|
*/
|
|
for (p = prev; p; p = rb_next(p)) {
|
|
struct active_node *node =
|
|
rb_entry(p, struct active_node, node);
|
|
struct intel_engine_cs *engine;
|
|
|
|
if (node->timeline > idx)
|
|
break;
|
|
|
|
if (node->timeline < idx)
|
|
continue;
|
|
|
|
if (is_idle_barrier(node, idx))
|
|
goto match;
|
|
|
|
/*
|
|
* The list of pending barriers is protected by the
|
|
* kernel_context timeline, which notably we do not hold
|
|
* here. i915_request_add_active_barriers() may consume
|
|
* the barrier before we claim it, so we have to check
|
|
* for success.
|
|
*/
|
|
engine = __barrier_to_engine(node);
|
|
smp_rmb(); /* serialise with add_active_barriers */
|
|
if (is_barrier(&node->base) &&
|
|
____active_del_barrier(ref, node, engine))
|
|
goto match;
|
|
}
|
|
|
|
spin_unlock_irq(&ref->tree_lock);
|
|
|
|
return NULL;
|
|
|
|
match:
|
|
rb_erase(p, &ref->tree); /* Hide from waits and sibling allocations */
|
|
if (p == &ref->cache->node)
|
|
ref->cache = NULL;
|
|
spin_unlock_irq(&ref->tree_lock);
|
|
|
|
return rb_entry(p, struct active_node, node);
|
|
}
|
|
|
|
int i915_active_acquire_preallocate_barrier(struct i915_active *ref,
|
|
struct intel_engine_cs *engine)
|
|
{
|
|
intel_engine_mask_t tmp, mask = engine->mask;
|
|
struct llist_node *first = NULL, *last = NULL;
|
|
struct intel_gt *gt = engine->gt;
|
|
int err;
|
|
|
|
GEM_BUG_ON(i915_active_is_idle(ref));
|
|
|
|
/* Wait until the previous preallocation is completed */
|
|
while (!llist_empty(&ref->preallocated_barriers))
|
|
cond_resched();
|
|
|
|
/*
|
|
* Preallocate a node for each physical engine supporting the target
|
|
* engine (remember virtual engines have more than one sibling).
|
|
* We can then use the preallocated nodes in
|
|
* i915_active_acquire_barrier()
|
|
*/
|
|
GEM_BUG_ON(!mask);
|
|
for_each_engine_masked(engine, gt, mask, tmp) {
|
|
u64 idx = engine->kernel_context->timeline->fence_context;
|
|
struct llist_node *prev = first;
|
|
struct active_node *node;
|
|
|
|
node = reuse_idle_barrier(ref, idx);
|
|
if (!node) {
|
|
node = kmem_cache_alloc(global.slab_cache, GFP_KERNEL);
|
|
if (!node) {
|
|
err = ENOMEM;
|
|
goto unwind;
|
|
}
|
|
|
|
RCU_INIT_POINTER(node->base.fence, NULL);
|
|
node->base.cb.func = node_retire;
|
|
node->timeline = idx;
|
|
node->ref = ref;
|
|
}
|
|
|
|
if (!i915_active_fence_isset(&node->base)) {
|
|
/*
|
|
* Mark this as being *our* unconnected proto-node.
|
|
*
|
|
* Since this node is not in any list, and we have
|
|
* decoupled it from the rbtree, we can reuse the
|
|
* request to indicate this is an idle-barrier node
|
|
* and then we can use the rb_node and list pointers
|
|
* for our tracking of the pending barrier.
|
|
*/
|
|
RCU_INIT_POINTER(node->base.fence, ERR_PTR(-EAGAIN));
|
|
node->base.cb.node.prev = (void *)engine;
|
|
atomic_inc(&ref->count);
|
|
}
|
|
GEM_BUG_ON(rcu_access_pointer(node->base.fence) != ERR_PTR(-EAGAIN));
|
|
|
|
GEM_BUG_ON(barrier_to_engine(node) != engine);
|
|
first = barrier_to_ll(node);
|
|
first->next = prev;
|
|
if (!last)
|
|
last = first;
|
|
intel_engine_pm_get(engine);
|
|
}
|
|
|
|
GEM_BUG_ON(!llist_empty(&ref->preallocated_barriers));
|
|
llist_add_batch(first, last, &ref->preallocated_barriers);
|
|
|
|
return 0;
|
|
|
|
unwind:
|
|
while (first) {
|
|
struct active_node *node = barrier_from_ll(first);
|
|
|
|
first = first->next;
|
|
|
|
atomic_dec(&ref->count);
|
|
intel_engine_pm_put(barrier_to_engine(node));
|
|
|
|
kmem_cache_free(global.slab_cache, node);
|
|
}
|
|
return err;
|
|
}
|
|
|
|
void i915_active_acquire_barrier(struct i915_active *ref)
|
|
{
|
|
struct llist_node *pos, *next;
|
|
unsigned long flags;
|
|
|
|
GEM_BUG_ON(i915_active_is_idle(ref));
|
|
|
|
/*
|
|
* Transfer the list of preallocated barriers into the
|
|
* i915_active rbtree, but only as proto-nodes. They will be
|
|
* populated by i915_request_add_active_barriers() to point to the
|
|
* request that will eventually release them.
|
|
*/
|
|
llist_for_each_safe(pos, next, take_preallocated_barriers(ref)) {
|
|
struct active_node *node = barrier_from_ll(pos);
|
|
struct intel_engine_cs *engine = barrier_to_engine(node);
|
|
struct rb_node **p, *parent;
|
|
|
|
spin_lock_irqsave_nested(&ref->tree_lock, flags,
|
|
SINGLE_DEPTH_NESTING);
|
|
parent = NULL;
|
|
p = &ref->tree.rb_node;
|
|
while (*p) {
|
|
struct active_node *it;
|
|
|
|
parent = *p;
|
|
|
|
it = rb_entry(parent, struct active_node, node);
|
|
if (it->timeline < node->timeline)
|
|
p = &parent->rb_right;
|
|
else
|
|
p = &parent->rb_left;
|
|
}
|
|
rb_link_node(&node->node, parent, p);
|
|
rb_insert_color(&node->node, &ref->tree);
|
|
spin_unlock_irqrestore(&ref->tree_lock, flags);
|
|
|
|
GEM_BUG_ON(!intel_engine_pm_is_awake(engine));
|
|
llist_add(barrier_to_ll(node), &engine->barrier_tasks);
|
|
intel_engine_pm_put_delay(engine, 1);
|
|
}
|
|
}
|
|
|
|
static struct dma_fence **ll_to_fence_slot(struct llist_node *node)
|
|
{
|
|
return __active_fence_slot(&barrier_from_ll(node)->base);
|
|
}
|
|
|
|
void i915_request_add_active_barriers(struct i915_request *rq)
|
|
{
|
|
struct intel_engine_cs *engine = rq->engine;
|
|
struct llist_node *node, *next;
|
|
unsigned long flags;
|
|
|
|
GEM_BUG_ON(!intel_context_is_barrier(rq->context));
|
|
GEM_BUG_ON(intel_engine_is_virtual(engine));
|
|
GEM_BUG_ON(i915_request_timeline(rq) != engine->kernel_context->timeline);
|
|
|
|
node = llist_del_all(&engine->barrier_tasks);
|
|
if (!node)
|
|
return;
|
|
/*
|
|
* Attach the list of proto-fences to the in-flight request such
|
|
* that the parent i915_active will be released when this request
|
|
* is retired.
|
|
*/
|
|
spin_lock_irqsave(&rq->lock, flags);
|
|
llist_for_each_safe(node, next, node) {
|
|
/* serialise with reuse_idle_barrier */
|
|
smp_store_mb(*ll_to_fence_slot(node), &rq->fence);
|
|
list_add_tail((struct list_head *)node, &rq->fence.cb_list);
|
|
}
|
|
spin_unlock_irqrestore(&rq->lock, flags);
|
|
}
|
|
|
|
/*
|
|
* __i915_active_fence_set: Update the last active fence along its timeline
|
|
* @active: the active tracker
|
|
* @fence: the new fence (under construction)
|
|
*
|
|
* Records the new @fence as the last active fence along its timeline in
|
|
* this active tracker, moving the tracking callbacks from the previous
|
|
* fence onto this one. Returns the previous fence (if not already completed),
|
|
* which the caller must ensure is executed before the new fence. To ensure
|
|
* that the order of fences within the timeline of the i915_active_fence is
|
|
* understood, it should be locked by the caller.
|
|
*/
|
|
struct dma_fence *
|
|
__i915_active_fence_set(struct i915_active_fence *active,
|
|
struct dma_fence *fence)
|
|
{
|
|
struct dma_fence *prev;
|
|
unsigned long flags;
|
|
|
|
if (fence == rcu_access_pointer(active->fence))
|
|
return fence;
|
|
|
|
GEM_BUG_ON(test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags));
|
|
|
|
/*
|
|
* Consider that we have two threads arriving (A and B), with
|
|
* C already resident as the active->fence.
|
|
*
|
|
* A does the xchg first, and so it sees C or NULL depending
|
|
* on the timing of the interrupt handler. If it is NULL, the
|
|
* previous fence must have been signaled and we know that
|
|
* we are first on the timeline. If it is still present,
|
|
* we acquire the lock on that fence and serialise with the interrupt
|
|
* handler, in the process removing it from any future interrupt
|
|
* callback. A will then wait on C before executing (if present).
|
|
*
|
|
* As B is second, it sees A as the previous fence and so waits for
|
|
* it to complete its transition and takes over the occupancy for
|
|
* itself -- remembering that it needs to wait on A before executing.
|
|
*
|
|
* Note the strong ordering of the timeline also provides consistent
|
|
* nesting rules for the fence->lock; the inner lock is always the
|
|
* older lock.
|
|
*/
|
|
spin_lock_irqsave(fence->lock, flags);
|
|
prev = xchg(__active_fence_slot(active), fence);
|
|
if (prev) {
|
|
GEM_BUG_ON(prev == fence);
|
|
spin_lock_nested(prev->lock, SINGLE_DEPTH_NESTING);
|
|
__list_del_entry(&active->cb.node);
|
|
spin_unlock(prev->lock); /* serialise with prev->cb_list */
|
|
}
|
|
list_add_tail(&active->cb.node, &fence->cb_list);
|
|
spin_unlock_irqrestore(fence->lock, flags);
|
|
|
|
return prev;
|
|
}
|
|
|
|
int i915_active_fence_set(struct i915_active_fence *active,
|
|
struct i915_request *rq)
|
|
{
|
|
struct dma_fence *fence;
|
|
int err = 0;
|
|
|
|
/* Must maintain timeline ordering wrt previous active requests */
|
|
rcu_read_lock();
|
|
fence = __i915_active_fence_set(active, &rq->fence);
|
|
if (fence) /* but the previous fence may not belong to that timeline! */
|
|
fence = dma_fence_get_rcu(fence);
|
|
rcu_read_unlock();
|
|
if (fence) {
|
|
err = i915_request_await_dma_fence(rq, fence);
|
|
dma_fence_put(fence);
|
|
}
|
|
|
|
return err;
|
|
}
|
|
|
|
void i915_active_noop(struct dma_fence *fence, struct dma_fence_cb *cb)
|
|
{
|
|
active_fence_cb(fence, cb);
|
|
}
|
|
|
|
struct auto_active {
|
|
struct i915_active base;
|
|
struct kref ref;
|
|
};
|
|
|
|
struct i915_active *i915_active_get(struct i915_active *ref)
|
|
{
|
|
struct auto_active *aa = container_of(ref, typeof(*aa), base);
|
|
|
|
kref_get(&aa->ref);
|
|
return &aa->base;
|
|
}
|
|
|
|
static void auto_release(struct kref *ref)
|
|
{
|
|
struct auto_active *aa = container_of(ref, typeof(*aa), ref);
|
|
|
|
i915_active_fini(&aa->base);
|
|
kfree(aa);
|
|
}
|
|
|
|
void i915_active_put(struct i915_active *ref)
|
|
{
|
|
struct auto_active *aa = container_of(ref, typeof(*aa), base);
|
|
|
|
kref_put(&aa->ref, auto_release);
|
|
}
|
|
|
|
static int auto_active(struct i915_active *ref)
|
|
{
|
|
i915_active_get(ref);
|
|
return 0;
|
|
}
|
|
|
|
static void auto_retire(struct i915_active *ref)
|
|
{
|
|
i915_active_put(ref);
|
|
}
|
|
|
|
struct i915_active *i915_active_create(void)
|
|
{
|
|
struct auto_active *aa;
|
|
|
|
aa = kmalloc(sizeof(*aa), GFP_KERNEL);
|
|
if (!aa)
|
|
return NULL;
|
|
|
|
kref_init(&aa->ref);
|
|
i915_active_init(&aa->base, auto_active, auto_retire);
|
|
|
|
return &aa->base;
|
|
}
|
|
|
|
#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
|
|
#include "selftests/i915_active.c"
|
|
#endif
|
|
|
|
static void i915_global_active_shrink(void)
|
|
{
|
|
kmem_cache_shrink(global.slab_cache);
|
|
}
|
|
|
|
static void i915_global_active_exit(void)
|
|
{
|
|
kmem_cache_destroy(global.slab_cache);
|
|
}
|
|
|
|
static struct i915_global_active global = { {
|
|
.shrink = i915_global_active_shrink,
|
|
.exit = i915_global_active_exit,
|
|
} };
|
|
|
|
int __init i915_global_active_init(void)
|
|
{
|
|
global.slab_cache = KMEM_CACHE(active_node, SLAB_HWCACHE_ALIGN);
|
|
if (!global.slab_cache)
|
|
return -ENOMEM;
|
|
|
|
i915_global_register(&global.base);
|
|
return 0;
|
|
}
|