diff options
Diffstat (limited to 'drivers/gpu/drm/i915/i915_request.h')
| -rw-r--r-- | drivers/gpu/drm/i915/i915_request.h | 902 |
1 files changed, 457 insertions, 445 deletions
diff --git a/drivers/gpu/drm/i915/i915_request.h b/drivers/gpu/drm/i915/i915_request.h index 90e9d170a0cd..b09135301f39 100644 --- a/drivers/gpu/drm/i915/i915_request.h +++ b/drivers/gpu/drm/i915/i915_request.h @@ -26,37 +26,154 @@ #define I915_REQUEST_H #include <linux/dma-fence.h> +#include <linux/hrtimer.h> +#include <linux/irq_work.h> +#include <linux/llist.h> +#include <linux/lockdep.h> + +#include <uapi/drm/i915_drm.h> + +#include "gem/i915_gem_context_types.h" +#include "gt/intel_context_types.h" +#include "gt/intel_engine_types.h" +#include "gt/intel_timeline_types.h" #include "i915_gem.h" +#include "i915_ptr_util.h" #include "i915_scheduler.h" +#include "i915_selftest.h" #include "i915_sw_fence.h" -#include "i915_scheduler.h" - -#include <uapi/drm/i915_drm.h> +#include "i915_vma_resource.h" struct drm_file; struct drm_i915_gem_object; +struct drm_printer; +struct i915_deps; struct i915_request; -struct i915_timeline; -struct intel_wait { - struct rb_node node; - struct task_struct *tsk; - struct i915_request *request; - u32 seqno; +#if IS_ENABLED(CONFIG_DRM_I915_CAPTURE_ERROR) +struct i915_capture_list { + struct i915_vma_resource *vma_res; + struct i915_capture_list *next; }; -struct intel_signal_node { - struct intel_wait wait; - struct list_head link; -}; +void i915_request_free_capture_list(struct i915_capture_list *capture); +#else +#define i915_request_free_capture_list(_a) do {} while (0) +#endif -struct i915_capture_list { - struct i915_capture_list *next; - struct i915_vma *vma; +#define RQ_TRACE(rq, fmt, ...) do { \ + const struct i915_request *rq__ = (rq); \ + ENGINE_TRACE(rq__->engine, "fence %llx:%lld, current %d " fmt, \ + rq__->fence.context, rq__->fence.seqno, \ + hwsp_seqno(rq__), ##__VA_ARGS__); \ +} while (0) + +enum { + /* + * I915_FENCE_FLAG_ACTIVE - this request is currently submitted to HW. + * + * Set by __i915_request_submit() on handing over to HW, and cleared + * by __i915_request_unsubmit() if we preempt this request. + * + * Finally cleared for consistency on retiring the request, when + * we know the HW is no longer running this request. + * + * See i915_request_is_active() + */ + I915_FENCE_FLAG_ACTIVE = DMA_FENCE_FLAG_USER_BITS, + + /* + * I915_FENCE_FLAG_PQUEUE - this request is ready for execution + * + * Using the scheduler, when a request is ready for execution it is put + * into the priority queue, and removed from that queue when transferred + * to the HW runlists. We want to track its membership within the + * priority queue so that we can easily check before rescheduling. + * + * See i915_request_in_priority_queue() + */ + I915_FENCE_FLAG_PQUEUE, + + /* + * I915_FENCE_FLAG_HOLD - this request is currently on hold + * + * This request has been suspended, pending an ongoing investigation. + */ + I915_FENCE_FLAG_HOLD, + + /* + * I915_FENCE_FLAG_INITIAL_BREADCRUMB - this request has the initial + * breadcrumb that marks the end of semaphore waits and start of the + * user payload. + */ + I915_FENCE_FLAG_INITIAL_BREADCRUMB, + + /* + * I915_FENCE_FLAG_SIGNAL - this request is currently on signal_list + * + * Internal bookkeeping used by the breadcrumb code to track when + * a request is on the various signal_list. + */ + I915_FENCE_FLAG_SIGNAL, + + /* + * I915_FENCE_FLAG_NOPREEMPT - this request should not be preempted + * + * The execution of some requests should not be interrupted. This is + * a sensitive operation as it makes the request super important, + * blocking other higher priority work. Abuse of this flag will + * lead to quality of service issues. + */ + I915_FENCE_FLAG_NOPREEMPT, + + /* + * I915_FENCE_FLAG_SENTINEL - this request should be last in the queue + * + * A high priority sentinel request may be submitted to clear the + * submission queue. As it will be the only request in-flight, upon + * execution all other active requests will have been preempted and + * unsubmitted. This preemptive pulse is used to re-evaluate the + * in-flight requests, particularly in cases where an active context + * is banned and those active requests need to be cancelled. + */ + I915_FENCE_FLAG_SENTINEL, + + /* + * I915_FENCE_FLAG_BOOST - upclock the gpu for this request + * + * Some requests are more important than others! In particular, a + * request that the user is waiting on is typically required for + * interactive latency, for which we want to minimise by upclocking + * the GPU. Here we track such boost requests on a per-request basis. + */ + I915_FENCE_FLAG_BOOST, + + /* + * I915_FENCE_FLAG_SUBMIT_PARALLEL - request with a context in a + * parent-child relationship (parallel submission, multi-lrc) should + * trigger a submission to the GuC rather than just moving the context + * tail. + */ + I915_FENCE_FLAG_SUBMIT_PARALLEL, + + /* + * I915_FENCE_FLAG_SKIP_PARALLEL - request with a context in a + * parent-child relationship (parallel submission, multi-lrc) that + * hit an error while generating requests in the execbuf IOCTL. + * Indicates this request should be skipped as another request in + * submission / relationship encountered an error. + */ + I915_FENCE_FLAG_SKIP_PARALLEL, + + /* + * I915_FENCE_FLAG_COMPOSITE - Indicates fence is part of a composite + * fence (dma_fence_array) and i915 generated for parallel submission. + */ + I915_FENCE_FLAG_COMPOSITE, }; -/** +/* * Request queue structure. * * The request queue allows us to note sequence numbers that have been emitted @@ -71,7 +188,7 @@ struct i915_capture_list { * RCU lookup of it that may race against reallocation of the struct * from the slab freelist. We intentionally do not zero the structure on * allocation so that the lookup can use the dangling pointers (and is - * cogniscent that those pointers may be wrong). Instead, everything that + * cognisant that those pointers may be wrong). Instead, everything that * needs to be initialised must be done so explicitly. * * The requests are reference counted. @@ -80,10 +197,9 @@ struct i915_request { struct dma_fence fence; spinlock_t lock; - /** On Which ring this request was generated */ struct drm_i915_private *i915; - /** + /* * Context and ring buffer related to this request * Contexts are refcounted, so when this request is associated with a * context, we must increment the context's refcount, to guarantee that @@ -93,12 +209,13 @@ struct i915_request { * i915_request_free() will then decrement the refcount on the * context. */ - struct i915_gem_context *gem_context; struct intel_engine_cs *engine; - struct intel_context *hw_context; + struct intel_context *context; struct intel_ring *ring; - struct i915_timeline *timeline; - struct intel_signal_node signaling; + struct intel_timeline __rcu *timeline; + + struct list_head signal_link; + struct llist_node signal_node; /* * The rcu epoch of when this request was allocated. Used to judiciously @@ -109,6 +226,15 @@ struct i915_request { unsigned long rcustate; /* + * We pin the timeline->mutex while constructing the request to + * ensure that no caller accidentally drops it during construction. + * The timeline->mutex must be held to ensure that only this caller + * can use the ring and manipulate the associated timeline during + * construction. + */ + struct pin_cookie cookie; + + /* * Fences for the various phases in the request's lifetime. * * The submit fence is used to await upon all of the request's @@ -116,8 +242,21 @@ struct i915_request { * It is used by the driver to then queue the request for execution. */ struct i915_sw_fence submit; - wait_queue_entry_t submitq; - wait_queue_head_t execute; + union { + wait_queue_entry_t submitq; + struct i915_sw_dma_fence_cb dmaq; + struct i915_request_duration_cb { + struct dma_fence_cb cb; + ktime_t emitted; + } duration; + }; + struct llist_head execute_cb; + struct i915_sw_fence semaphore; + /* + * complete submit fence from an IRQ if needed for locking hierarchy + * reasons. + */ + struct irq_work submit_work; /* * A list of everyone we wait upon, and everyone who waits upon us. @@ -130,64 +269,95 @@ struct i915_request { */ struct i915_sched_node sched; struct i915_dependency dep; + intel_engine_mask_t execution_mask; - /** - * GEM sequence number associated with this request on the - * global execution timeline. It is zero when the request is not - * on the HW queue (i.e. not on the engine timeline list). - * Its value is guarded by the timeline spinlock. + /* + * A convenience pointer to the current breadcrumb value stored in + * the HW status page (or our timeline's local equivalent). The full + * path would be rq->hw_context->ring->timeline->hwsp_seqno. */ - u32 global_seqno; + const u32 *hwsp_seqno; - /** Position in the ring of the start of the request */ + /* Position in the ring of the start of the request */ u32 head; - /** Position in the ring of the start of the user packets */ + /* Position in the ring of the start of the user packets */ u32 infix; - /** + /* * Position in the ring of the start of the postfix. * This is required to calculate the maximum available ring space * without overwriting the postfix. */ u32 postfix; - /** Position in the ring of the end of the whole request */ + /* Position in the ring of the end of the whole request */ u32 tail; - /** Position in the ring of the end of any workarounds after the tail */ + /* Position in the ring of the end of any workarounds after the tail */ u32 wa_tail; - /** Preallocate space in the ring for the emitting the request */ + /* Preallocate space in the ring for the emitting the request */ u32 reserved_space; - /** Batch buffer related to this request if any (used for - * error state dump only). - */ - struct i915_vma *batch; - /** + /* Batch buffer pointer for selftest internal use. */ + I915_SELFTEST_DECLARE(struct i915_vma *batch); + + struct i915_vma_resource *batch_res; + +#if IS_ENABLED(CONFIG_DRM_I915_CAPTURE_ERROR) + /* * Additional buffers requested by userspace to be captured upon * a GPU hang. The vma/obj on this list are protected by their * active reference - all objects on this list must also be * on the active_list (of their final request). */ struct i915_capture_list *capture_list; - struct list_head active_list; +#endif - /** Time at which this request was emitted, in jiffies. */ + /* Time at which this request was emitted, in jiffies. */ unsigned long emitted_jiffies; - bool waitboost; - - /** engine->request_list entry for this request */ + /* timeline->request entry for this request */ struct list_head link; - /** ring->request_list entry for this request */ - struct list_head ring_link; + /* Watchdog support fields. */ + struct i915_request_watchdog { + struct llist_node link; + struct hrtimer timer; + } watchdog; - struct drm_i915_file_private *file_priv; - /** file_priv list entry for this request */ - struct list_head client_link; + /* + * Requests may need to be stalled when using GuC submission waiting for + * certain GuC operations to complete. If that is the case, stalled + * requests are added to a per context list of stalled requests. The + * below list_head is the link in that list. Protected by + * ce->guc_state.lock. + */ + struct list_head guc_fence_link; + + /* + * Priority level while the request is in flight. Differs + * from i915 scheduler priority. See comment above + * I915_SCHEDULER_CAP_STATIC_PRIORITY_MAP for details. Protected by + * ce->guc_active.lock. Two special values (GUC_PRIO_INIT and + * GUC_PRIO_FINI) outside the GuC priority range are used to indicate + * if the priority has not been initialized yet or if no more updates + * are possible because the request has completed. + */ +#define GUC_PRIO_INIT 0xff +#define GUC_PRIO_FINI 0xfe + u8 guc_prio; + + /* + * wait queue entry used to wait on the HuC load to complete + */ + wait_queue_entry_t hucq; + + I915_SELFTEST_DECLARE(struct { + struct list_head link; + unsigned long delay; + } mock;) }; #define I915_FENCE_GFP (GFP_KERNEL | __GFP_RETRY_MAYFAIL | __GFP_NOWARN) @@ -199,9 +369,23 @@ static inline bool dma_fence_is_i915(const struct dma_fence *fence) return fence->ops == &i915_fence_ops; } +struct kmem_cache *i915_request_slab_cache(void); + struct i915_request * __must_check -i915_request_alloc(struct intel_engine_cs *engine, - struct i915_gem_context *ctx); +__i915_request_create(struct intel_context *ce, gfp_t gfp); +struct i915_request * __must_check +i915_request_create(struct intel_context *ce); + +void __i915_request_skip(struct i915_request *rq); +bool i915_request_set_error_once(struct i915_request *rq, int error); +struct i915_request *i915_request_mark_eio(struct i915_request *rq); + +struct i915_request *__i915_request_commit(struct i915_request *request); +void __i915_request_queue(struct i915_request *rq, + const struct i915_sched_attr *attr); +void __i915_request_queue_bh(struct i915_request *rq); + +bool i915_request_retire(struct i915_request *rq); void i915_request_retire_upto(struct i915_request *rq); static inline struct i915_request * @@ -231,491 +415,319 @@ i915_request_put(struct i915_request *rq) dma_fence_put(&rq->fence); } -/** - * i915_request_global_seqno - report the current global seqno - * @request - the request - * - * A request is assigned a global seqno only when it is on the hardware - * execution queue. The global seqno can be used to maintain a list of - * requests on the same engine in retirement order, for example for - * constructing a priority queue for waiting. Prior to its execution, or - * if it is subsequently removed in the event of preemption, its global - * seqno is zero. As both insertion and removal from the execution queue - * may operate in IRQ context, it is not guarded by the usual struct_mutex - * BKL. Instead those relying on the global seqno must be prepared for its - * value to change between reads. Only when the request is complete can - * the global seqno be stable (due to the memory barriers on submitting - * the commands to the hardware to write the breadcrumb, if the HWS shows - * that it has passed the global seqno and the global seqno is unchanged - * after the read, it is indeed complete). - */ -static u32 -i915_request_global_seqno(const struct i915_request *request) -{ - return READ_ONCE(request->global_seqno); -} - int i915_request_await_object(struct i915_request *to, struct drm_i915_gem_object *obj, bool write); int i915_request_await_dma_fence(struct i915_request *rq, struct dma_fence *fence); +int i915_request_await_deps(struct i915_request *rq, const struct i915_deps *deps); +int i915_request_await_execution(struct i915_request *rq, + struct dma_fence *fence); void i915_request_add(struct i915_request *rq); -void __i915_request_submit(struct i915_request *request); +bool __i915_request_submit(struct i915_request *request); void i915_request_submit(struct i915_request *request); -void i915_request_skip(struct i915_request *request, int error); - void __i915_request_unsubmit(struct i915_request *request); void i915_request_unsubmit(struct i915_request *request); +void i915_request_cancel(struct i915_request *rq, int error); + +long i915_request_wait_timeout(struct i915_request *rq, + unsigned int flags, + long timeout) + __attribute__((nonnull(1))); + long i915_request_wait(struct i915_request *rq, unsigned int flags, long timeout) __attribute__((nonnull(1))); #define I915_WAIT_INTERRUPTIBLE BIT(0) -#define I915_WAIT_LOCKED BIT(1) /* struct_mutex held, handle GPU reset */ -#define I915_WAIT_PRIORITY BIT(2) /* small priority bump for the request */ -#define I915_WAIT_ALL BIT(3) /* used by i915_gem_object_wait() */ -#define I915_WAIT_FOR_IDLE_BOOST BIT(4) +#define I915_WAIT_PRIORITY BIT(1) /* small priority bump for the request */ +#define I915_WAIT_ALL BIT(2) /* used by i915_gem_object_wait() */ -static inline bool intel_engine_has_started(struct intel_engine_cs *engine, - u32 seqno); -static inline bool intel_engine_has_completed(struct intel_engine_cs *engine, - u32 seqno); +void i915_request_show(struct drm_printer *m, + const struct i915_request *rq, + const char *prefix, + int indent); -/** - * Returns true if seq1 is later than seq2. - */ -static inline bool i915_seqno_passed(u32 seq1, u32 seq2) +static inline bool i915_request_signaled(const struct i915_request *rq) { - return (s32)(seq1 - seq2) >= 0; + /* The request may live longer than its HWSP, so check flags first! */ + return test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &rq->fence.flags); } -/** - * i915_request_started - check if the request has begun being executed - * @rq: the request - * - * Returns true if the request has been submitted to hardware, and the hardware - * has advanced passed the end of the previous request and so should be either - * currently processing the request (though it may be preempted and so - * not necessarily the next request to complete) or have completed the request. - */ -static inline bool i915_request_started(const struct i915_request *rq) +static inline bool i915_request_is_active(const struct i915_request *rq) { - u32 seqno; - - seqno = i915_request_global_seqno(rq); - if (!seqno) /* not yet submitted to HW */ - return false; + return test_bit(I915_FENCE_FLAG_ACTIVE, &rq->fence.flags); +} - return intel_engine_has_started(rq->engine, seqno); +static inline bool i915_request_in_priority_queue(const struct i915_request *rq) +{ + return test_bit(I915_FENCE_FLAG_PQUEUE, &rq->fence.flags); } static inline bool -__i915_request_completed(const struct i915_request *rq, u32 seqno) +i915_request_has_initial_breadcrumb(const struct i915_request *rq) { - GEM_BUG_ON(!seqno); - return intel_engine_has_completed(rq->engine, seqno) && - seqno == i915_request_global_seqno(rq); + return test_bit(I915_FENCE_FLAG_INITIAL_BREADCRUMB, &rq->fence.flags); } -static inline bool i915_request_completed(const struct i915_request *rq) +/* + * Returns true if seq1 is later than seq2. + */ +static inline bool i915_seqno_passed(u32 seq1, u32 seq2) { - u32 seqno; + return (s32)(seq1 - seq2) >= 0; +} - seqno = i915_request_global_seqno(rq); - if (!seqno) - return false; +static inline u32 __hwsp_seqno(const struct i915_request *rq) +{ + const u32 *hwsp = READ_ONCE(rq->hwsp_seqno); - return __i915_request_completed(rq, seqno); + return READ_ONCE(*hwsp); } -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. +/** + * hwsp_seqno - the current breadcrumb value in the HW status page + * @rq: the request, to chase the relevant HW status page * - * 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(). + * The emphasis in naming here is that hwsp_seqno() is not a property of the + * request, but an indication of the current HW state (associated with this + * request). Its value will change as the GPU executes more requests. * - * 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. + * Returns the current breadcrumb value in the associated HW status page (or + * the local timeline's equivalent) for this request. The request itself + * has the associated breadcrumb value of rq->fence.seqno, when the HW + * status page has that breadcrumb or later, this request is complete. */ -struct i915_gem_active; +static inline u32 hwsp_seqno(const struct i915_request *rq) +{ + u32 seqno; -typedef void (*i915_gem_retire_fn)(struct i915_gem_active *, - struct i915_request *); + rcu_read_lock(); /* the HWSP may be freed at runtime */ + seqno = __hwsp_seqno(rq); + rcu_read_unlock(); -struct i915_gem_active { - struct i915_request __rcu *request; - struct list_head link; - i915_gem_retire_fn retire; -}; + return seqno; +} -void i915_gem_retire_noop(struct i915_gem_active *, - struct i915_request *request); +static inline bool __i915_request_has_started(const struct i915_request *rq) +{ + return i915_seqno_passed(__hwsp_seqno(rq), rq->fence.seqno - 1); +} /** - * 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 + * i915_request_started - check if the request has begun being executed + * @rq: the request + * + * If the timeline is not using initial breadcrumbs, a request is + * considered started if the previous request on its timeline (i.e. + * context) has been signaled. * - * 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. + * If the timeline is using semaphores, it will also be emitting an + * "initial breadcrumb" after the semaphores are complete and just before + * it began executing the user payload. A request can therefore be active + * on the HW and not yet started as it is still busywaiting on its + * dependencies (via HW semaphores). + * + * If the request has started, its dependencies will have been signaled + * (either by fences or by semaphores) and it will have begun processing + * the user payload. + * + * However, even if a request has started, it may have been preempted and + * so no longer active, or it may have already completed. + * + * See also i915_request_is_active(). + * + * Returns true if the request has begun executing the user payload, or + * has completed: */ -static inline void -init_request_active(struct i915_gem_active *active, - i915_gem_retire_fn retire) +static inline bool i915_request_started(const struct i915_request *rq) { - RCU_INIT_POINTER(active->request, NULL); - INIT_LIST_HEAD(&active->link); - active->retire = retire ?: i915_gem_retire_noop; + bool result; + + if (i915_request_signaled(rq)) + return true; + + result = true; + rcu_read_lock(); /* the HWSP may be freed at runtime */ + if (likely(!i915_request_signaled(rq))) + /* Remember: started but may have since been preempted! */ + result = __i915_request_has_started(rq); + rcu_read_unlock(); + + return result; } /** - * i915_gem_active_set - updates the tracker to watch the current request - * @active - the active tracker - * @request - the request to watch + * i915_request_is_running - check if the request may actually be executing + * @rq: the request * - * 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. + * Returns true if the request is currently submitted to hardware, has passed + * its start point (i.e. the context is setup and not busywaiting). Note that + * it may no longer be running by the time the function returns! */ -static inline void -i915_gem_active_set(struct i915_gem_active *active, - struct i915_request *request) +static inline bool i915_request_is_running(const struct i915_request *rq) { - list_move(&active->link, &request->active_list); - rcu_assign_pointer(active->request, request); + bool result; + + if (!i915_request_is_active(rq)) + return false; + + rcu_read_lock(); + result = __i915_request_has_started(rq) && i915_request_is_active(rq); + rcu_read_unlock(); + + return result; } /** - * 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_request_is_ready - check if the request is ready for execution + * @rq: the request * - * i915_gem_active_set_retire_fn() updates the function pointer that - * is called when the final request associated with the @active tracker - * is retired. + * Upon construction, the request is instructed to wait upon various + * signals before it is ready to be executed by the HW. That is, we do + * not want to start execution and read data before it is written. In practice, + * this is controlled with a mixture of interrupts and semaphores. Once + * the submit fence is completed, the backend scheduler will place the + * request into its queue and from there submit it for execution. So we + * can detect when a request is eligible for execution (and is under control + * of the scheduler) by querying where it is in any of the scheduler's lists. + * + * Returns true if the request is ready for execution (it may be inflight), + * false otherwise. */ -static inline void -i915_gem_active_set_retire_fn(struct i915_gem_active *active, - i915_gem_retire_fn fn, - struct mutex *mutex) +static inline bool i915_request_is_ready(const struct i915_request *rq) { - lockdep_assert_held(mutex); - active->retire = fn ?: i915_gem_retire_noop; + return !list_empty(&rq->sched.link); } -static inline struct i915_request * -__i915_gem_active_peek(const struct i915_gem_active *active) +static inline bool __i915_request_is_complete(const struct i915_request *rq) { - /* - * 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); + return i915_seqno_passed(__hwsp_seqno(rq), rq->fence.seqno); } -/** - * 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) +static inline bool i915_request_completed(const struct i915_request *rq) { - return rcu_dereference_protected(active->request, - lockdep_is_held(mutex)); -} + bool result; -/** - * 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; + if (i915_request_signaled(rq)) + return true; - request = i915_gem_active_raw(active, mutex); - if (!request || i915_request_completed(request)) - return NULL; + result = true; + rcu_read_lock(); /* the HWSP may be freed at runtime */ + if (likely(!i915_request_signaled(rq))) + result = __i915_request_is_complete(rq); + rcu_read_unlock(); - return request; + return result; } -/** - * 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) +static inline void i915_request_mark_complete(struct i915_request *rq) { - return i915_request_get(i915_gem_active_peek(active, mutex)); + WRITE_ONCE(rq->hwsp_seqno, /* decouple from HWSP */ + (u32 *)&rq->fence.seqno); } -/** - * __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) +static inline bool i915_request_has_waitboost(const struct i915_request *rq) { - /* - * 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); + return test_bit(I915_FENCE_FLAG_BOOST, &rq->fence.flags); } -/** - * 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) +static inline bool i915_request_has_nopreempt(const struct i915_request *rq) { - struct i915_request *request; + /* Preemption should only be disabled very rarely */ + return unlikely(test_bit(I915_FENCE_FLAG_NOPREEMPT, &rq->fence.flags)); +} - rcu_read_lock(); - request = __i915_gem_active_get_rcu(active); - rcu_read_unlock(); +static inline bool i915_request_has_sentinel(const struct i915_request *rq) +{ + return unlikely(test_bit(I915_FENCE_FLAG_SENTINEL, &rq->fence.flags)); +} - return request; +static inline bool i915_request_on_hold(const struct i915_request *rq) +{ + return unlikely(test_bit(I915_FENCE_FLAG_HOLD, &rq->fence.flags)); } -/** - * 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) +static inline void i915_request_set_hold(struct i915_request *rq) { - return rcu_access_pointer(active->request); + set_bit(I915_FENCE_FLAG_HOLD, &rq->fence.flags); } -/** - * 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) +static inline void i915_request_clear_hold(struct i915_request *rq) { - struct i915_request *request; - long ret = 0; + clear_bit(I915_FENCE_FLAG_HOLD, &rq->fence.flags); +} - request = i915_gem_active_get_unlocked(active); - if (request) { - ret = i915_request_wait(request, flags, MAX_SCHEDULE_TIMEOUT); - i915_request_put(request); - } +static inline struct intel_timeline * +i915_request_timeline(const struct i915_request *rq) +{ + /* Valid only while the request is being constructed (or retired). */ + return rcu_dereference_protected(rq->timeline, + lockdep_is_held(&rcu_access_pointer(rq->timeline)->mutex) || + test_bit(CONTEXT_IS_PARKING, &rq->context->flags)); +} - return ret < 0 ? ret : 0; +static inline struct i915_gem_context * +i915_request_gem_context(const struct i915_request *rq) +{ + /* Valid only while the request is being constructed (or retired). */ + return rcu_dereference_protected(rq->context->gem_context, true); } -/** - * 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) +static inline struct intel_timeline * +i915_request_active_timeline(const struct i915_request *rq) +{ + /* + * When in use during submission, we are protected by a guarantee that + * the context/timeline is pinned and must remain pinned until after + * this submission. + */ + return rcu_dereference_protected(rq->timeline, + lockdep_is_held(&rq->engine->sched_engine->lock)); +} + +static inline u32 +i915_request_active_seqno(const struct i915_request *rq) { - struct i915_request *request; - long ret; + u32 hwsp_phys_base = + page_mask_bits(i915_request_active_timeline(rq)->hwsp_offset); + u32 hwsp_relative_offset = offset_in_page(rq->hwsp_seqno); - request = i915_gem_active_raw(active, mutex); - if (!request) - return 0; + /* + * Because of wraparound, we cannot simply take tl->hwsp_offset, + * but instead use the fact that the relative for vaddr is the + * offset as for hwsp_offset. Take the top bits from tl->hwsp_offset + * and combine them with the relative offset in rq->hwsp_seqno. + * + * As rw->hwsp_seqno is rewritten when signaled, this only works + * when the request isn't signaled yet, but at that point you + * no longer need the offset. + */ - ret = i915_request_wait(request, - I915_WAIT_INTERRUPTIBLE | I915_WAIT_LOCKED, - MAX_SCHEDULE_TIMEOUT); - if (ret < 0) - return ret; + return hwsp_phys_base + hwsp_relative_offset; +} - list_del_init(&active->link); - RCU_INIT_POINTER(active->request, NULL); +bool +i915_request_active_engine(struct i915_request *rq, + struct intel_engine_cs **active); - active->retire(active, request); +void i915_request_notify_execute_cb_imm(struct i915_request *rq); - return 0; -} +enum i915_request_state { + I915_REQUEST_UNKNOWN = 0, + I915_REQUEST_COMPLETE, + I915_REQUEST_PENDING, + I915_REQUEST_QUEUED, + I915_REQUEST_ACTIVE, +}; + +enum i915_request_state i915_test_request_state(struct i915_request *rq); -#define for_each_active(mask, idx) \ - for (; mask ? idx = ffs(mask) - 1, 1 : 0; mask &= ~BIT(idx)) +void i915_request_module_exit(void); +int i915_request_module_init(void); #endif /* I915_REQUEST_H */ |