} global;
struct active_node {
- struct i915_gem_active base;
+ struct i915_active_request base;
struct i915_active *ref;
struct rb_node node;
u64 timeline;
struct active_node *it, *n;
rbtree_postorder_for_each_entry_safe(it, n, &ref->tree, node) {
- GEM_BUG_ON(i915_gem_active_isset(&it->base));
+ GEM_BUG_ON(i915_active_request_isset(&it->base));
kmem_cache_free(global.slab_cache, it);
}
ref->tree = RB_ROOT;
}
static void
-node_retire(struct i915_gem_active *base, struct i915_request *rq)
+node_retire(struct i915_active_request *base, struct i915_request *rq)
{
__active_retire(container_of(base, struct active_node, base)->ref);
}
static void
-last_retire(struct i915_gem_active *base, struct i915_request *rq)
+last_retire(struct i915_active_request *base, struct i915_request *rq)
{
__active_retire(container_of(base, struct i915_active, last));
}
-static struct i915_gem_active *
+static struct i915_active_request *
active_instance(struct i915_active *ref, u64 idx)
{
struct active_node *node;
* twice for the same timeline (as the older rbtree element will be
* retired before the new request added to last).
*/
- old = i915_gem_active_raw(&ref->last, BKL(ref));
+ old = i915_active_request_raw(&ref->last, BKL(ref));
if (!old || old->fence.context == idx)
goto out;
node = kmem_cache_alloc(global.slab_cache, GFP_KERNEL);
/* kmalloc may retire the ref->last (thanks shrinker)! */
- if (unlikely(!i915_gem_active_raw(&ref->last, BKL(ref)))) {
+ if (unlikely(!i915_active_request_raw(&ref->last, BKL(ref)))) {
kmem_cache_free(global.slab_cache, node);
goto out;
}
if (unlikely(!node))
return ERR_PTR(-ENOMEM);
- init_request_active(&node->base, node_retire);
+ i915_active_request_init(&node->base, NULL, node_retire);
node->ref = ref;
node->timeline = idx;
* callback not two, and so much undo the active counting for the
* overwritten slot.
*/
- if (i915_gem_active_isset(&node->base)) {
+ if (i915_active_request_isset(&node->base)) {
/* Retire ourselves from the old rq->active_list */
__list_del_entry(&node->base.link);
ref->count--;
ref->i915 = i915;
ref->retire = retire;
ref->tree = RB_ROOT;
- init_request_active(&ref->last, last_retire);
+ i915_active_request_init(&ref->last, NULL, last_retire);
ref->count = 0;
}
u64 timeline,
struct i915_request *rq)
{
- struct i915_gem_active *active;
+ struct i915_active_request *active;
active = active_instance(ref, timeline);
if (IS_ERR(active))
return PTR_ERR(active);
- if (!i915_gem_active_isset(active))
+ if (!i915_active_request_isset(active))
ref->count++;
- i915_gem_active_set(active, rq);
+ __i915_active_request_set(active, rq);
GEM_BUG_ON(!ref->count);
return 0;
if (i915_active_acquire(ref))
goto out_release;
- ret = i915_gem_active_retire(&ref->last, BKL(ref));
+ ret = i915_active_request_retire(&ref->last, BKL(ref));
if (ret)
goto out_release;
rbtree_postorder_for_each_entry_safe(it, n, &ref->tree, node) {
- ret = i915_gem_active_retire(&it->base, BKL(ref));
+ ret = i915_active_request_retire(&it->base, BKL(ref));
if (ret)
break;
}
return ret;
}
-static int __i915_request_await_active(struct i915_request *rq,
- struct i915_gem_active *active)
+int i915_request_await_active_request(struct i915_request *rq,
+ struct i915_active_request *active)
{
struct i915_request *barrier =
- i915_gem_active_raw(active, &rq->i915->drm.struct_mutex);
+ i915_active_request_raw(active, &rq->i915->drm.struct_mutex);
return barrier ? i915_request_await_dma_fence(rq, &barrier->fence) : 0;
}
struct active_node *it, *n;
int ret;
- ret = __i915_request_await_active(rq, &ref->last);
+ ret = i915_request_await_active_request(rq, &ref->last);
if (ret)
return ret;
rbtree_postorder_for_each_entry_safe(it, n, &ref->tree, node) {
- ret = __i915_request_await_active(rq, &it->base);
+ ret = i915_request_await_active_request(rq, &it->base);
if (ret)
return ret;
}
#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM)
void i915_active_fini(struct i915_active *ref)
{
- GEM_BUG_ON(i915_gem_active_isset(&ref->last));
+ GEM_BUG_ON(i915_active_request_isset(&ref->last));
GEM_BUG_ON(!RB_EMPTY_ROOT(&ref->tree));
GEM_BUG_ON(ref->count);
}
#endif
+int i915_active_request_set(struct i915_active_request *active,
+ struct i915_request *rq)
+{
+ int err;
+
+ /* Must maintain ordering wrt previous active requests */
+ err = i915_request_await_active_request(rq, active);
+ if (err)
+ return err;
+
+ __i915_active_request_set(active, rq);
+ return 0;
+}
+
+void i915_active_retire_noop(struct i915_active_request *active,
+ struct i915_request *request)
+{
+ /* Space left intentionally blank */
+}
+
#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
#include "selftests/i915_active.c"
#endif
#ifndef _I915_ACTIVE_H_
#define _I915_ACTIVE_H_
+#include <linux/lockdep.h>
+
#include "i915_active_types.h"
+#include "i915_request.h"
+
+/*
+ * We treat requests as fences. This is not be to confused with our
+ * "fence registers" but pipeline synchronisation objects ala GL_ARB_sync.
+ * We use the fences to synchronize access from the CPU with activity on the
+ * GPU, for example, we should not rewrite an object's PTE whilst the GPU
+ * is reading them. We also track fences at a higher level to provide
+ * implicit synchronisation around GEM objects, e.g. set-domain will wait
+ * for outstanding GPU rendering before marking the object ready for CPU
+ * access, or a pageflip will wait until the GPU is complete before showing
+ * the frame on the scanout.
+ *
+ * In order to use a fence, the object must track the fence it needs to
+ * serialise with. For example, GEM objects want to track both read and
+ * write access so that we can perform concurrent read operations between
+ * the CPU and GPU engines, as well as waiting for all rendering to
+ * complete, or waiting for the last GPU user of a "fence register". The
+ * object then embeds a #i915_active_request to track the most recent (in
+ * retirement order) request relevant for the desired mode of access.
+ * The #i915_active_request is updated with i915_active_request_set() to
+ * track the most recent fence request, typically this is done as part of
+ * i915_vma_move_to_active().
+ *
+ * When the #i915_active_request completes (is retired), it will
+ * signal its completion to the owner through a callback as well as mark
+ * itself as idle (i915_active_request.request == NULL). The owner
+ * can then perform any action, such as delayed freeing of an active
+ * resource including itself.
+ */
+
+void i915_active_retire_noop(struct i915_active_request *active,
+ struct i915_request *request);
+
+/**
+ * i915_active_request_init - prepares the activity tracker for use
+ * @active - the active tracker
+ * @rq - initial request to track, can be NULL
+ * @func - a callback when then the tracker is retired (becomes idle),
+ * can be NULL
+ *
+ * i915_active_request_init() prepares the embedded @active struct for use as
+ * an activity tracker, that is for tracking the last known active request
+ * associated with it. When the last request becomes idle, when it is retired
+ * after completion, the optional callback @func is invoked.
+ */
+static inline void
+i915_active_request_init(struct i915_active_request *active,
+ struct i915_request *rq,
+ i915_active_retire_fn retire)
+{
+ RCU_INIT_POINTER(active->request, rq);
+ INIT_LIST_HEAD(&active->link);
+ active->retire = retire ?: i915_active_retire_noop;
+}
+
+#define INIT_ACTIVE_REQUEST(name) i915_active_request_init((name), NULL, NULL)
+
+/**
+ * i915_active_request_set - updates the tracker to watch the current request
+ * @active - the active tracker
+ * @request - the request to watch
+ *
+ * __i915_active_request_set() watches the given @request for completion. Whilst
+ * that @request is busy, the @active reports busy. When that @request is
+ * retired, the @active tracker is updated to report idle.
+ */
+static inline void
+__i915_active_request_set(struct i915_active_request *active,
+ struct i915_request *request)
+{
+ list_move(&active->link, &request->active_list);
+ rcu_assign_pointer(active->request, request);
+}
+
+int __must_check
+i915_active_request_set(struct i915_active_request *active,
+ struct i915_request *rq);
+
+/**
+ * i915_active_request_set_retire_fn - updates the retirement callback
+ * @active - the active tracker
+ * @fn - the routine called when the request is retired
+ * @mutex - struct_mutex used to guard retirements
+ *
+ * i915_active_request_set_retire_fn() updates the function pointer that
+ * is called when the final request associated with the @active tracker
+ * is retired.
+ */
+static inline void
+i915_active_request_set_retire_fn(struct i915_active_request *active,
+ i915_active_retire_fn fn,
+ struct mutex *mutex)
+{
+ lockdep_assert_held(mutex);
+ active->retire = fn ?: i915_active_retire_noop;
+}
+
+static inline struct i915_request *
+__i915_active_request_peek(const struct i915_active_request *active)
+{
+ /*
+ * Inside the error capture (running with the driver in an unknown
+ * state), we want to bend the rules slightly (a lot).
+ *
+ * Work is in progress to make it safer, in the meantime this keeps
+ * the known issue from spamming the logs.
+ */
+ return rcu_dereference_protected(active->request, 1);
+}
+
+/**
+ * i915_active_request_raw - return the active request
+ * @active - the active tracker
+ *
+ * i915_active_request_raw() returns the current request being tracked, or NULL.
+ * It does not obtain a reference on the request for the caller, so the caller
+ * must hold struct_mutex.
+ */
+static inline struct i915_request *
+i915_active_request_raw(const struct i915_active_request *active,
+ struct mutex *mutex)
+{
+ return rcu_dereference_protected(active->request,
+ lockdep_is_held(mutex));
+}
+
+/**
+ * i915_active_request_peek - report the active request being monitored
+ * @active - the active tracker
+ *
+ * i915_active_request_peek() returns the current request being tracked if
+ * still active, or NULL. It does not obtain a reference on the request
+ * for the caller, so the caller must hold struct_mutex.
+ */
+static inline struct i915_request *
+i915_active_request_peek(const struct i915_active_request *active,
+ struct mutex *mutex)
+{
+ struct i915_request *request;
+
+ request = i915_active_request_raw(active, mutex);
+ if (!request || i915_request_completed(request))
+ return NULL;
+
+ return request;
+}
+
+/**
+ * i915_active_request_get - return a reference to the active request
+ * @active - the active tracker
+ *
+ * i915_active_request_get() returns a reference to the active request, or NULL
+ * if the active tracker is idle. The caller must hold struct_mutex.
+ */
+static inline struct i915_request *
+i915_active_request_get(const struct i915_active_request *active,
+ struct mutex *mutex)
+{
+ return i915_request_get(i915_active_request_peek(active, mutex));
+}
+
+/**
+ * __i915_active_request_get_rcu - return a reference to the active request
+ * @active - the active tracker
+ *
+ * __i915_active_request_get() returns a reference to the active request,
+ * or NULL if the active tracker is idle. The caller must hold the RCU read
+ * lock, but the returned pointer is safe to use outside of RCU.
+ */
+static inline struct i915_request *
+__i915_active_request_get_rcu(const struct i915_active_request *active)
+{
+ /*
+ * Performing a lockless retrieval of the active request is super
+ * tricky. SLAB_TYPESAFE_BY_RCU merely guarantees that the backing
+ * slab of request objects will not be freed whilst we hold the
+ * RCU read lock. It does not guarantee that the request itself
+ * will not be freed and then *reused*. Viz,
+ *
+ * Thread A Thread B
+ *
+ * rq = active.request
+ * retire(rq) -> free(rq);
+ * (rq is now first on the slab freelist)
+ * active.request = NULL
+ *
+ * rq = new submission on a new object
+ * ref(rq)
+ *
+ * To prevent the request from being reused whilst the caller
+ * uses it, we take a reference like normal. Whilst acquiring
+ * the reference we check that it is not in a destroyed state
+ * (refcnt == 0). That prevents the request being reallocated
+ * whilst the caller holds on to it. To check that the request
+ * was not reallocated as we acquired the reference we have to
+ * check that our request remains the active request across
+ * the lookup, in the same manner as a seqlock. The visibility
+ * of the pointer versus the reference counting is controlled
+ * by using RCU barriers (rcu_dereference and rcu_assign_pointer).
+ *
+ * In the middle of all that, we inspect whether the request is
+ * complete. Retiring is lazy so the request may be completed long
+ * before the active tracker is updated. Querying whether the
+ * request is complete is far cheaper (as it involves no locked
+ * instructions setting cachelines to exclusive) than acquiring
+ * the reference, so we do it first. The RCU read lock ensures the
+ * pointer dereference is valid, but does not ensure that the
+ * seqno nor HWS is the right one! However, if the request was
+ * reallocated, that means the active tracker's request was complete.
+ * If the new request is also complete, then both are and we can
+ * just report the active tracker is idle. If the new request is
+ * incomplete, then we acquire a reference on it and check that
+ * it remained the active request.
+ *
+ * It is then imperative that we do not zero the request on
+ * reallocation, so that we can chase the dangling pointers!
+ * See i915_request_alloc().
+ */
+ do {
+ struct i915_request *request;
+
+ request = rcu_dereference(active->request);
+ if (!request || i915_request_completed(request))
+ return NULL;
+
+ /*
+ * An especially silly compiler could decide to recompute the
+ * result of i915_request_completed, more specifically
+ * re-emit the load for request->fence.seqno. A race would catch
+ * a later seqno value, which could flip the result from true to
+ * false. Which means part of the instructions below might not
+ * be executed, while later on instructions are executed. Due to
+ * barriers within the refcounting the inconsistency can't reach
+ * past the call to i915_request_get_rcu, but not executing
+ * that while still executing i915_request_put() creates
+ * havoc enough. Prevent this with a compiler barrier.
+ */
+ barrier();
+
+ request = i915_request_get_rcu(request);
+
+ /*
+ * What stops the following rcu_access_pointer() from occurring
+ * before the above i915_request_get_rcu()? If we were
+ * to read the value before pausing to get the reference to
+ * the request, we may not notice a change in the active
+ * tracker.
+ *
+ * The rcu_access_pointer() is a mere compiler barrier, which
+ * means both the CPU and compiler are free to perform the
+ * memory read without constraint. The compiler only has to
+ * ensure that any operations after the rcu_access_pointer()
+ * occur afterwards in program order. This means the read may
+ * be performed earlier by an out-of-order CPU, or adventurous
+ * compiler.
+ *
+ * The atomic operation at the heart of
+ * i915_request_get_rcu(), see dma_fence_get_rcu(), is
+ * atomic_inc_not_zero() which is only a full memory barrier
+ * when successful. That is, if i915_request_get_rcu()
+ * returns the request (and so with the reference counted
+ * incremented) then the following read for rcu_access_pointer()
+ * must occur after the atomic operation and so confirm
+ * that this request is the one currently being tracked.
+ *
+ * The corresponding write barrier is part of
+ * rcu_assign_pointer().
+ */
+ if (!request || request == rcu_access_pointer(active->request))
+ return rcu_pointer_handoff(request);
+
+ i915_request_put(request);
+ } while (1);
+}
+
+/**
+ * i915_active_request_get_unlocked - return a reference to the active request
+ * @active - the active tracker
+ *
+ * i915_active_request_get_unlocked() returns a reference to the active request,
+ * or NULL if the active tracker is idle. The reference is obtained under RCU,
+ * so no locking is required by the caller.
+ *
+ * The reference should be freed with i915_request_put().
+ */
+static inline struct i915_request *
+i915_active_request_get_unlocked(const struct i915_active_request *active)
+{
+ struct i915_request *request;
+
+ rcu_read_lock();
+ request = __i915_active_request_get_rcu(active);
+ rcu_read_unlock();
+
+ return request;
+}
+
+/**
+ * i915_active_request_isset - report whether the active tracker is assigned
+ * @active - the active tracker
+ *
+ * i915_active_request_isset() returns true if the active tracker is currently
+ * assigned to a request. Due to the lazy retiring, that request may be idle
+ * and this may report stale information.
+ */
+static inline bool
+i915_active_request_isset(const struct i915_active_request *active)
+{
+ return rcu_access_pointer(active->request);
+}
+
+/**
+ * i915_active_request_retire - waits until the request is retired
+ * @active - the active request on which to wait
+ *
+ * i915_active_request_retire() waits until the request is completed,
+ * and then ensures that at least the retirement handler for this
+ * @active tracker is called before returning. If the @active
+ * tracker is idle, the function returns immediately.
+ */
+static inline int __must_check
+i915_active_request_retire(struct i915_active_request *active,
+ struct mutex *mutex)
+{
+ struct i915_request *request;
+ long ret;
+
+ request = i915_active_request_raw(active, mutex);
+ if (!request)
+ return 0;
+
+ ret = i915_request_wait(request,
+ I915_WAIT_INTERRUPTIBLE | I915_WAIT_LOCKED,
+ MAX_SCHEDULE_TIMEOUT);
+ if (ret < 0)
+ return ret;
+
+ list_del_init(&active->link);
+ RCU_INIT_POINTER(active->request, NULL);
+
+ active->retire(active, request);
+
+ return 0;
+}
/*
* GPU activity tracking
int i915_request_await_active(struct i915_request *rq,
struct i915_active *ref);
+int i915_request_await_active_request(struct i915_request *rq,
+ struct i915_active_request *active);
bool i915_active_acquire(struct i915_active *ref);
#define _I915_ACTIVE_TYPES_H_
#include <linux/rbtree.h>
-
-#include "i915_request.h"
+#include <linux/rcupdate.h>
struct drm_i915_private;
+struct i915_active_request;
+struct i915_request;
+
+typedef void (*i915_active_retire_fn)(struct i915_active_request *,
+ struct i915_request *);
+
+struct i915_active_request {
+ struct i915_request __rcu *request;
+ struct list_head link;
+ i915_active_retire_fn retire;
+};
struct i915_active {
struct drm_i915_private *i915;
struct rb_root tree;
- struct i915_gem_active last;
+ struct i915_active_request last;
unsigned int count;
void (*retire)(struct i915_active *ref);
if (vma->fence)
seq_printf(m, " , fence: %d%s",
vma->fence->id,
- i915_gem_active_isset(&vma->last_fence) ? "*" : "");
+ i915_active_request_isset(&vma->last_fence) ? "*" : "");
seq_puts(m, ")");
}
if (obj->stolen)
GEM_BUG_ON(i915->gt.active_requests);
for_each_engine(engine, i915, id) {
- GEM_BUG_ON(__i915_gem_active_peek(&engine->timeline.last_request));
+ GEM_BUG_ON(__i915_active_request_peek(&engine->timeline.last_request));
GEM_BUG_ON(engine->last_retired_context !=
to_intel_context(i915->kernel_context, engine));
}
list_for_each_entry(tl, >->active_list, link) {
struct i915_request *rq;
- rq = i915_gem_active_get_unlocked(&tl->last_request);
+ rq = i915_active_request_get_unlocked(&tl->last_request);
if (!rq)
continue;
}
static void
-frontbuffer_retire(struct i915_gem_active *active, struct i915_request *request)
+frontbuffer_retire(struct i915_active_request *active,
+ struct i915_request *request)
{
struct drm_i915_gem_object *obj =
container_of(active, typeof(*obj), frontbuffer_write);
obj->resv = &obj->__builtin_resv;
obj->frontbuffer_ggtt_origin = ORIGIN_GTT;
- init_request_active(&obj->frontbuffer_write, frontbuffer_retire);
+ i915_active_request_init(&obj->frontbuffer_write,
+ NULL, frontbuffer_retire);
obj->mm.madv = I915_MADV_WILLNEED;
INIT_RADIX_TREE(&obj->mm.get_page.radix, GFP_KERNEL | __GFP_NOWARN);
return desc;
}
-static void intel_context_retire(struct i915_gem_active *active,
+static void intel_context_retire(struct i915_active_request *active,
struct i915_request *rq)
{
struct intel_context *ce =
/* Use the whole device by default */
ce->sseu = intel_device_default_sseu(ctx->i915);
- init_request_active(&ce->active_tracker, intel_context_retire);
+ i915_active_request_init(&ce->active_tracker,
+ NULL, intel_context_retire);
}
static struct i915_gem_context *
GEM_BUG_ON(timeline == &engine->timeline);
- rq = i915_gem_active_raw(&timeline->last_request,
- &engine->i915->drm.struct_mutex);
+ rq = i915_active_request_raw(&timeline->last_request,
+ &engine->i915->drm.struct_mutex);
if (rq && rq->engine == engine) {
GEM_TRACE("last request for %s on engine %s: %llx:%llu\n",
timeline->name, engine->name,
}
/* Queue this switch after all other activity by this context. */
- prev = i915_gem_active_raw(&ce->ring->timeline->last_request,
- &i915->drm.struct_mutex);
+ prev = i915_active_request_raw(&ce->ring->timeline->last_request,
+ &i915->drm.struct_mutex);
if (prev && !i915_request_completed(prev)) {
ret = i915_request_await_dma_fence(rq, &prev->fence);
if (ret < 0)
* But we only need to take one pin on the account of it. Or in other
* words transfer the pinned ce object to tracked active request.
*/
- if (!i915_gem_active_isset(&ce->active_tracker))
+ if (!i915_active_request_isset(&ce->active_tracker))
__intel_context_pin(ce);
- i915_gem_active_set(&ce->active_tracker, rq);
+ __i915_active_request_set(&ce->active_tracker, rq);
out_add:
i915_request_add(rq);
* active_tracker: Active tracker for the external rq activity
* on this intel_context object.
*/
- struct i915_gem_active active_tracker;
+ struct i915_active_request active_tracker;
const struct intel_context_ops *ops;
i915_gem_object_get_tiling(vma->obj)))
return -EINVAL;
- ret = i915_gem_active_retire(&vma->last_fence,
+ ret = i915_active_request_retire(&vma->last_fence,
&vma->obj->base.dev->struct_mutex);
if (ret)
return ret;
if (fence->vma) {
struct i915_vma *old = fence->vma;
- ret = i915_gem_active_retire(&old->last_fence,
+ ret = i915_active_request_retire(&old->last_fence,
&old->obj->base.dev->struct_mutex);
if (ret)
return ret;
return ERR_PTR(-ENOMEM);
i915_active_init(i915, &vma->active, NULL);
- init_request_active(&vma->last_fence, NULL);
+ INIT_ACTIVE_REQUEST(&vma->last_fence);
vma->vm = &ggtt->vm;
vma->ops = &pd_vma_ops;
atomic_t frontbuffer_bits;
unsigned int frontbuffer_ggtt_origin; /* write once */
- struct i915_gem_active frontbuffer_write;
+ struct i915_active_request frontbuffer_write;
/** Current tiling stride for the object, if it's tiled. */
unsigned int tiling_and_stride;
}
/* The error capture is special as tries to run underneath the normal
- * locking rules - so we use the raw version of the i915_gem_active lookup.
+ * locking rules - so we use the raw version of the i915_active_request lookup.
*/
static inline u32
-__active_get_seqno(struct i915_gem_active *active)
+__active_get_seqno(struct i915_active_request *active)
{
struct i915_request *request;
- request = __i915_gem_active_peek(active);
+ request = __i915_active_request_peek(active);
return request ? request->global_seqno : 0;
}
static inline int
-__active_get_engine_id(struct i915_gem_active *active)
+__active_get_engine_id(struct i915_active_request *active)
{
struct i915_request *request;
- request = __i915_gem_active_peek(active);
+ request = __i915_active_request_peek(active);
return request ? request->engine->id : -1;
}
#include <linux/sched/signal.h>
#include "i915_drv.h"
+#include "i915_active.h"
#include "i915_reset.h"
static const char *i915_fence_get_driver_name(struct dma_fence *fence)
i915_gem_park(i915);
}
-void i915_gem_retire_noop(struct i915_gem_active *active,
- struct i915_request *request)
-{
- /* Space left intentionally blank */
-}
-
static void advance_ring(struct i915_request *request)
{
struct intel_ring *ring = request->ring;
static void i915_request_retire(struct i915_request *request)
{
- struct i915_gem_active *active, *next;
+ struct i915_active_request *active, *next;
GEM_TRACE("%s fence %llx:%lld, global=%d, current %d:%d\n",
request->engine->name,
* we may spend an inordinate amount of time simply handling
* the retirement of requests and processing their callbacks.
* Of which, this loop itself is particularly hot due to the
- * cache misses when jumping around the list of i915_gem_active.
- * So we try to keep this loop as streamlined as possible and
- * also prefetch the next i915_gem_active to try and hide
- * the likely cache miss.
+ * cache misses when jumping around the list of
+ * i915_active_request. So we try to keep this loop as
+ * streamlined as possible and also prefetch the next
+ * i915_active_request to try and hide the likely cache miss.
*/
prefetchw(next);
return kmem_cache_alloc(ce->gem_context->i915->requests, GFP_KERNEL);
}
-static int add_barrier(struct i915_request *rq, struct i915_gem_active *active)
-{
- struct i915_request *barrier =
- i915_gem_active_raw(active, &rq->i915->drm.struct_mutex);
-
- return barrier ? i915_request_await_dma_fence(rq, &barrier->fence) : 0;
-}
-
static int add_timeline_barrier(struct i915_request *rq)
{
- return add_barrier(rq, &rq->timeline->barrier);
+ return i915_request_await_active_request(rq, &rq->timeline->barrier);
}
/**
* We use RCU to look up requests in flight. The lookups may
* race with the request being allocated from the slab freelist.
* That is the request we are writing to here, may be in the process
- * of being read by __i915_gem_active_get_rcu(). As such,
+ * of being read by __i915_active_request_get_rcu(). As such,
* we have to be very careful when overwriting the contents. During
* the RCU lookup, we change chase the request->engine pointer,
* read the request->global_seqno and increment the reference count.
* see a more recent value in the hws than we are tracking.
*/
- prev = i915_gem_active_raw(&timeline->last_request,
- &request->i915->drm.struct_mutex);
+ prev = i915_active_request_raw(&timeline->last_request,
+ &request->i915->drm.struct_mutex);
if (prev && !i915_request_completed(prev)) {
i915_sw_fence_await_sw_fence(&request->submit, &prev->submit,
&request->submitq);
spin_unlock_irq(&timeline->lock);
GEM_BUG_ON(timeline->seqno != request->fence.seqno);
- i915_gem_active_set(&timeline->last_request, request);
+ __i915_active_request_set(&timeline->last_request, request);
list_add_tail(&request->ring_link, &ring->request_list);
if (list_is_first(&request->ring_link, &ring->request_list)) {
void i915_retire_requests(struct drm_i915_private *i915);
-/*
- * We treat requests as fences. This is not be to confused with our
- * "fence registers" but pipeline synchronisation objects ala GL_ARB_sync.
- * We use the fences to synchronize access from the CPU with activity on the
- * GPU, for example, we should not rewrite an object's PTE whilst the GPU
- * is reading them. We also track fences at a higher level to provide
- * implicit synchronisation around GEM objects, e.g. set-domain will wait
- * for outstanding GPU rendering before marking the object ready for CPU
- * access, or a pageflip will wait until the GPU is complete before showing
- * the frame on the scanout.
- *
- * In order to use a fence, the object must track the fence it needs to
- * serialise with. For example, GEM objects want to track both read and
- * write access so that we can perform concurrent read operations between
- * the CPU and GPU engines, as well as waiting for all rendering to
- * complete, or waiting for the last GPU user of a "fence register". The
- * object then embeds a #i915_gem_active to track the most recent (in
- * retirement order) request relevant for the desired mode of access.
- * The #i915_gem_active is updated with i915_gem_active_set() to track the
- * most recent fence request, typically this is done as part of
- * i915_vma_move_to_active().
- *
- * When the #i915_gem_active completes (is retired), it will
- * signal its completion to the owner through a callback as well as mark
- * itself as idle (i915_gem_active.request == NULL). The owner
- * can then perform any action, such as delayed freeing of an active
- * resource including itself.
- */
-struct i915_gem_active;
-
-typedef void (*i915_gem_retire_fn)(struct i915_gem_active *,
- struct i915_request *);
-
-struct i915_gem_active {
- struct i915_request __rcu *request;
- struct list_head link;
- i915_gem_retire_fn retire;
-};
-
-void i915_gem_retire_noop(struct i915_gem_active *,
- struct i915_request *request);
-
-/**
- * init_request_active - prepares the activity tracker for use
- * @active - the active tracker
- * @func - a callback when then the tracker is retired (becomes idle),
- * can be NULL
- *
- * init_request_active() prepares the embedded @active struct for use as
- * an activity tracker, that is for tracking the last known active request
- * associated with it. When the last request becomes idle, when it is retired
- * after completion, the optional callback @func is invoked.
- */
-static inline void
-init_request_active(struct i915_gem_active *active,
- i915_gem_retire_fn retire)
-{
- RCU_INIT_POINTER(active->request, NULL);
- INIT_LIST_HEAD(&active->link);
- active->retire = retire ?: i915_gem_retire_noop;
-}
-
-/**
- * i915_gem_active_set - updates the tracker to watch the current request
- * @active - the active tracker
- * @request - the request to watch
- *
- * i915_gem_active_set() watches the given @request for completion. Whilst
- * that @request is busy, the @active reports busy. When that @request is
- * retired, the @active tracker is updated to report idle.
- */
-static inline void
-i915_gem_active_set(struct i915_gem_active *active,
- struct i915_request *request)
-{
- list_move(&active->link, &request->active_list);
- rcu_assign_pointer(active->request, request);
-}
-
-/**
- * i915_gem_active_set_retire_fn - updates the retirement callback
- * @active - the active tracker
- * @fn - the routine called when the request is retired
- * @mutex - struct_mutex used to guard retirements
- *
- * i915_gem_active_set_retire_fn() updates the function pointer that
- * is called when the final request associated with the @active tracker
- * is retired.
- */
-static inline void
-i915_gem_active_set_retire_fn(struct i915_gem_active *active,
- i915_gem_retire_fn fn,
- struct mutex *mutex)
-{
- lockdep_assert_held(mutex);
- active->retire = fn ?: i915_gem_retire_noop;
-}
-
-static inline struct i915_request *
-__i915_gem_active_peek(const struct i915_gem_active *active)
-{
- /*
- * Inside the error capture (running with the driver in an unknown
- * state), we want to bend the rules slightly (a lot).
- *
- * Work is in progress to make it safer, in the meantime this keeps
- * the known issue from spamming the logs.
- */
- return rcu_dereference_protected(active->request, 1);
-}
-
-/**
- * i915_gem_active_raw - return the active request
- * @active - the active tracker
- *
- * i915_gem_active_raw() returns the current request being tracked, or NULL.
- * It does not obtain a reference on the request for the caller, so the caller
- * must hold struct_mutex.
- */
-static inline struct i915_request *
-i915_gem_active_raw(const struct i915_gem_active *active, struct mutex *mutex)
-{
- return rcu_dereference_protected(active->request,
- lockdep_is_held(mutex));
-}
-
-/**
- * i915_gem_active_peek - report the active request being monitored
- * @active - the active tracker
- *
- * i915_gem_active_peek() returns the current request being tracked if
- * still active, or NULL. It does not obtain a reference on the request
- * for the caller, so the caller must hold struct_mutex.
- */
-static inline struct i915_request *
-i915_gem_active_peek(const struct i915_gem_active *active, struct mutex *mutex)
-{
- struct i915_request *request;
-
- request = i915_gem_active_raw(active, mutex);
- if (!request || i915_request_completed(request))
- return NULL;
-
- return request;
-}
-
-/**
- * i915_gem_active_get - return a reference to the active request
- * @active - the active tracker
- *
- * i915_gem_active_get() returns a reference to the active request, or NULL
- * if the active tracker is idle. The caller must hold struct_mutex.
- */
-static inline struct i915_request *
-i915_gem_active_get(const struct i915_gem_active *active, struct mutex *mutex)
-{
- return i915_request_get(i915_gem_active_peek(active, mutex));
-}
-
-/**
- * __i915_gem_active_get_rcu - return a reference to the active request
- * @active - the active tracker
- *
- * __i915_gem_active_get() returns a reference to the active request, or NULL
- * if the active tracker is idle. The caller must hold the RCU read lock, but
- * the returned pointer is safe to use outside of RCU.
- */
-static inline struct i915_request *
-__i915_gem_active_get_rcu(const struct i915_gem_active *active)
-{
- /*
- * Performing a lockless retrieval of the active request is super
- * tricky. SLAB_TYPESAFE_BY_RCU merely guarantees that the backing
- * slab of request objects will not be freed whilst we hold the
- * RCU read lock. It does not guarantee that the request itself
- * will not be freed and then *reused*. Viz,
- *
- * Thread A Thread B
- *
- * rq = active.request
- * retire(rq) -> free(rq);
- * (rq is now first on the slab freelist)
- * active.request = NULL
- *
- * rq = new submission on a new object
- * ref(rq)
- *
- * To prevent the request from being reused whilst the caller
- * uses it, we take a reference like normal. Whilst acquiring
- * the reference we check that it is not in a destroyed state
- * (refcnt == 0). That prevents the request being reallocated
- * whilst the caller holds on to it. To check that the request
- * was not reallocated as we acquired the reference we have to
- * check that our request remains the active request across
- * the lookup, in the same manner as a seqlock. The visibility
- * of the pointer versus the reference counting is controlled
- * by using RCU barriers (rcu_dereference and rcu_assign_pointer).
- *
- * In the middle of all that, we inspect whether the request is
- * complete. Retiring is lazy so the request may be completed long
- * before the active tracker is updated. Querying whether the
- * request is complete is far cheaper (as it involves no locked
- * instructions setting cachelines to exclusive) than acquiring
- * the reference, so we do it first. The RCU read lock ensures the
- * pointer dereference is valid, but does not ensure that the
- * seqno nor HWS is the right one! However, if the request was
- * reallocated, that means the active tracker's request was complete.
- * If the new request is also complete, then both are and we can
- * just report the active tracker is idle. If the new request is
- * incomplete, then we acquire a reference on it and check that
- * it remained the active request.
- *
- * It is then imperative that we do not zero the request on
- * reallocation, so that we can chase the dangling pointers!
- * See i915_request_alloc().
- */
- do {
- struct i915_request *request;
-
- request = rcu_dereference(active->request);
- if (!request || i915_request_completed(request))
- return NULL;
-
- /*
- * An especially silly compiler could decide to recompute the
- * result of i915_request_completed, more specifically
- * re-emit the load for request->fence.seqno. A race would catch
- * a later seqno value, which could flip the result from true to
- * false. Which means part of the instructions below might not
- * be executed, while later on instructions are executed. Due to
- * barriers within the refcounting the inconsistency can't reach
- * past the call to i915_request_get_rcu, but not executing
- * that while still executing i915_request_put() creates
- * havoc enough. Prevent this with a compiler barrier.
- */
- barrier();
-
- request = i915_request_get_rcu(request);
-
- /*
- * What stops the following rcu_access_pointer() from occurring
- * before the above i915_request_get_rcu()? If we were
- * to read the value before pausing to get the reference to
- * the request, we may not notice a change in the active
- * tracker.
- *
- * The rcu_access_pointer() is a mere compiler barrier, which
- * means both the CPU and compiler are free to perform the
- * memory read without constraint. The compiler only has to
- * ensure that any operations after the rcu_access_pointer()
- * occur afterwards in program order. This means the read may
- * be performed earlier by an out-of-order CPU, or adventurous
- * compiler.
- *
- * The atomic operation at the heart of
- * i915_request_get_rcu(), see dma_fence_get_rcu(), is
- * atomic_inc_not_zero() which is only a full memory barrier
- * when successful. That is, if i915_request_get_rcu()
- * returns the request (and so with the reference counted
- * incremented) then the following read for rcu_access_pointer()
- * must occur after the atomic operation and so confirm
- * that this request is the one currently being tracked.
- *
- * The corresponding write barrier is part of
- * rcu_assign_pointer().
- */
- if (!request || request == rcu_access_pointer(active->request))
- return rcu_pointer_handoff(request);
-
- i915_request_put(request);
- } while (1);
-}
-
-/**
- * i915_gem_active_get_unlocked - return a reference to the active request
- * @active - the active tracker
- *
- * i915_gem_active_get_unlocked() returns a reference to the active request,
- * or NULL if the active tracker is idle. The reference is obtained under RCU,
- * so no locking is required by the caller.
- *
- * The reference should be freed with i915_request_put().
- */
-static inline struct i915_request *
-i915_gem_active_get_unlocked(const struct i915_gem_active *active)
-{
- struct i915_request *request;
-
- rcu_read_lock();
- request = __i915_gem_active_get_rcu(active);
- rcu_read_unlock();
-
- return request;
-}
-
-/**
- * i915_gem_active_isset - report whether the active tracker is assigned
- * @active - the active tracker
- *
- * i915_gem_active_isset() returns true if the active tracker is currently
- * assigned to a request. Due to the lazy retiring, that request may be idle
- * and this may report stale information.
- */
-static inline bool
-i915_gem_active_isset(const struct i915_gem_active *active)
-{
- return rcu_access_pointer(active->request);
-}
-
-/**
- * i915_gem_active_wait - waits until the request is completed
- * @active - the active request on which to wait
- * @flags - how to wait
- * @timeout - how long to wait at most
- * @rps - userspace client to charge for a waitboost
- *
- * i915_gem_active_wait() waits until the request is completed before
- * returning, without requiring any locks to be held. Note that it does not
- * retire any requests before returning.
- *
- * This function relies on RCU in order to acquire the reference to the active
- * request without holding any locks. See __i915_gem_active_get_rcu() for the
- * glory details on how that is managed. Once the reference is acquired, we
- * can then wait upon the request, and afterwards release our reference,
- * free of any locking.
- *
- * This function wraps i915_request_wait(), see it for the full details on
- * the arguments.
- *
- * Returns 0 if successful, or a negative error code.
- */
-static inline int
-i915_gem_active_wait(const struct i915_gem_active *active, unsigned int flags)
-{
- struct i915_request *request;
- long ret = 0;
-
- request = i915_gem_active_get_unlocked(active);
- if (request) {
- ret = i915_request_wait(request, flags, MAX_SCHEDULE_TIMEOUT);
- i915_request_put(request);
- }
-
- return ret < 0 ? ret : 0;
-}
-
-/**
- * i915_gem_active_retire - waits until the request is retired
- * @active - the active request on which to wait
- *
- * i915_gem_active_retire() waits until the request is completed,
- * and then ensures that at least the retirement handler for this
- * @active tracker is called before returning. If the @active
- * tracker is idle, the function returns immediately.
- */
-static inline int __must_check
-i915_gem_active_retire(struct i915_gem_active *active,
- struct mutex *mutex)
-{
- struct i915_request *request;
- long ret;
-
- request = i915_gem_active_raw(active, mutex);
- if (!request)
- return 0;
-
- ret = i915_request_wait(request,
- I915_WAIT_INTERRUPTIBLE | I915_WAIT_LOCKED,
- MAX_SCHEDULE_TIMEOUT);
- if (ret < 0)
- return ret;
-
- list_del_init(&active->link);
- RCU_INIT_POINTER(active->request, NULL);
-
- active->retire(active, request);
-
- return 0;
-}
-
-#define for_each_active(mask, idx) \
- for (; mask ? idx = ffs(mask) - 1, 1 : 0; mask &= ~BIT(idx))
-
#endif /* I915_REQUEST_H */
struct i915_request *rq;
long timeout;
- rq = i915_gem_active_get_unlocked(&tl->last_request);
+ rq = i915_active_request_get_unlocked(&tl->last_request);
if (!rq)
continue;
spin_lock_init(&timeline->lock);
- init_request_active(&timeline->barrier, NULL);
- init_request_active(&timeline->last_request, NULL);
+ INIT_ACTIVE_REQUEST(&timeline->barrier);
+ INIT_ACTIVE_REQUEST(&timeline->last_request);
INIT_LIST_HEAD(&timeline->requests);
i915_syncmap_init(&timeline->sync);
{
GEM_BUG_ON(timeline->pin_count);
GEM_BUG_ON(!list_empty(&timeline->requests));
- GEM_BUG_ON(i915_gem_active_isset(&timeline->barrier));
+ GEM_BUG_ON(i915_active_request_isset(&timeline->barrier));
i915_syncmap_free(&timeline->sync);
hwsp_free(timeline);
__i915_vma_unpin(tl->hwsp_ggtt);
}
-int i915_timeline_set_barrier(struct i915_timeline *tl, struct i915_request *rq)
-{
- struct i915_request *old;
- int err;
-
- lockdep_assert_held(&rq->i915->drm.struct_mutex);
-
- /* Must maintain ordering wrt existing barriers */
- old = i915_gem_active_raw(&tl->barrier, &rq->i915->drm.struct_mutex);
- if (old) {
- err = i915_request_await_dma_fence(rq, &old->fence);
- if (err)
- return err;
- }
-
- i915_gem_active_set(&tl->barrier, rq);
- return 0;
-}
-
void __i915_timeline_free(struct kref *kref)
{
struct i915_timeline *timeline =
#include <linux/list.h>
#include <linux/kref.h>
+#include "i915_active.h"
#include "i915_request.h"
#include "i915_syncmap.h"
#include "i915_utils.h"
/* Contains an RCU guarded pointer to the last request. No reference is
* held to the request, users must carefully acquire a reference to
- * the request using i915_gem_active_get_request_rcu(), or hold the
+ * the request using i915_active_request_get_request_rcu(), or hold the
* struct_mutex.
*/
- struct i915_gem_active last_request;
+ struct i915_active_request last_request;
/**
* We track the most recent seqno that we wait on in every context so
* subsequent submissions to this timeline be executed only after the
* barrier has been completed.
*/
- struct i915_gem_active barrier;
+ struct i915_active_request barrier;
struct list_head link;
const char *name;
* submissions on @timeline. Subsequent requests will not be submitted to GPU
* until the barrier has been completed.
*/
-int i915_timeline_set_barrier(struct i915_timeline *timeline,
- struct i915_request *rq);
+static inline int
+i915_timeline_set_barrier(struct i915_timeline *tl, struct i915_request *rq)
+{
+ return i915_active_request_set(&tl->barrier, rq);
+}
#endif
return ERR_PTR(-ENOMEM);
i915_active_init(vm->i915, &vma->active, __i915_vma_retire);
- init_request_active(&vma->last_fence, NULL);
+ INIT_ACTIVE_REQUEST(&vma->last_fence);
vma->vm = vm;
vma->ops = &vm->vma_ops;
GEM_BUG_ON(vma->node.allocated);
GEM_BUG_ON(vma->fence);
- GEM_BUG_ON(i915_gem_active_isset(&vma->last_fence));
+ GEM_BUG_ON(i915_active_request_isset(&vma->last_fence));
mutex_lock(&vma->vm->mutex);
list_del(&vma->vm_link);
obj->write_domain = I915_GEM_DOMAIN_RENDER;
if (intel_fb_obj_invalidate(obj, ORIGIN_CS))
- i915_gem_active_set(&obj->frontbuffer_write, rq);
+ __i915_active_request_set(&obj->frontbuffer_write, rq);
obj->read_domains = 0;
}
obj->read_domains |= I915_GEM_GPU_DOMAINS;
if (flags & EXEC_OBJECT_NEEDS_FENCE)
- i915_gem_active_set(&vma->last_fence, rq);
+ __i915_active_request_set(&vma->last_fence, rq);
export_fence(vma, rq, flags);
return 0;
if (ret)
goto unpin;
- ret = i915_gem_active_retire(&vma->last_fence,
- &vma->vm->i915->drm.struct_mutex);
+ ret = i915_active_request_retire(&vma->last_fence,
+ &vma->vm->i915->drm.struct_mutex);
unpin:
__i915_vma_unpin(vma);
if (ret)
#define I915_VMA_GGTT_WRITE BIT(15)
struct i915_active active;
- struct i915_gem_active last_fence;
+ struct i915_active_request last_fence;
/**
* Support different GGTT views into the same object.
* the last request that remains in the timeline. When idle, it is
* the last executed context as tracked by retirement.
*/
- rq = __i915_gem_active_peek(&engine->timeline.last_request);
+ rq = __i915_active_request_peek(&engine->timeline.last_request);
if (rq)
return rq->hw_context == kernel_context;
else
struct overlay_registers __iomem *regs;
u32 flip_addr;
/* flip handling */
- struct i915_gem_active last_flip;
+ struct i915_active_request last_flip;
};
static void i830_overlay_clock_gating(struct drm_i915_private *dev_priv,
static void intel_overlay_submit_request(struct intel_overlay *overlay,
struct i915_request *rq,
- i915_gem_retire_fn retire)
+ i915_active_retire_fn retire)
{
- GEM_BUG_ON(i915_gem_active_peek(&overlay->last_flip,
- &overlay->i915->drm.struct_mutex));
- i915_gem_active_set_retire_fn(&overlay->last_flip, retire,
- &overlay->i915->drm.struct_mutex);
- i915_gem_active_set(&overlay->last_flip, rq);
+ GEM_BUG_ON(i915_active_request_peek(&overlay->last_flip,
+ &overlay->i915->drm.struct_mutex));
+ i915_active_request_set_retire_fn(&overlay->last_flip, retire,
+ &overlay->i915->drm.struct_mutex);
+ __i915_active_request_set(&overlay->last_flip, rq);
i915_request_add(rq);
}
static int intel_overlay_do_wait_request(struct intel_overlay *overlay,
struct i915_request *rq,
- i915_gem_retire_fn retire)
+ i915_active_retire_fn retire)
{
intel_overlay_submit_request(overlay, rq, retire);
- return i915_gem_active_retire(&overlay->last_flip,
- &overlay->i915->drm.struct_mutex);
+ return i915_active_request_retire(&overlay->last_flip,
+ &overlay->i915->drm.struct_mutex);
}
static struct i915_request *alloc_request(struct intel_overlay *overlay)
i915_vma_put(vma);
}
-static void intel_overlay_release_old_vid_tail(struct i915_gem_active *active,
- struct i915_request *rq)
+static void
+intel_overlay_release_old_vid_tail(struct i915_active_request *active,
+ struct i915_request *rq)
{
struct intel_overlay *overlay =
container_of(active, typeof(*overlay), last_flip);
intel_overlay_release_old_vma(overlay);
}
-static void intel_overlay_off_tail(struct i915_gem_active *active,
+static void intel_overlay_off_tail(struct i915_active_request *active,
struct i915_request *rq)
{
struct intel_overlay *overlay =
* We have to be careful not to repeat work forever an make forward progess. */
static int intel_overlay_recover_from_interrupt(struct intel_overlay *overlay)
{
- return i915_gem_active_retire(&overlay->last_flip,
- &overlay->i915->drm.struct_mutex);
+ return i915_active_request_retire(&overlay->last_flip,
+ &overlay->i915->drm.struct_mutex);
}
/* Wait for pending overlay flip and release old frame.
overlay->contrast = 75;
overlay->saturation = 146;
- init_request_active(&overlay->last_flip, NULL);
+ INIT_ACTIVE_REQUEST(&overlay->last_flip);
mutex_lock(&dev_priv->drm.struct_mutex);
spin_lock_init(&timeline->lock);
- init_request_active(&timeline->barrier, NULL);
- init_request_active(&timeline->last_request, NULL);
+ INIT_ACTIVE_REQUEST(&timeline->barrier);
+ INIT_ACTIVE_REQUEST(&timeline->last_request);
INIT_LIST_HEAD(&timeline->requests);
i915_syncmap_init(&timeline->sync);
projects / platform / kernel / linux-starfive.git / commitdiff