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drm/i915: Remove i915_request.global_seqno

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Having weaned the interrupt handling off using a single global execution
queue, we no longer need to emit a global_seqno. Note that we still have
a few assumptions about execution order along engine timelines, but this
removes the most obvious artefact!

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190226094922.31617-3-chris@chris-wilson.co.uk
This commit is contained in:
Chris Wilson
2019-02-26 09:49:21 +00:00
parent 8892f47742
commit b300fde896
12 changed files with 32 additions and 194 deletions
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32
drivers/gpu/drm/i915/i915_request.h
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@@ -147,14 +147,6 @@ struct i915_request {
*/
const u32 *hwsp_seqno;
/**
* 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.
*/
u32 global_seqno;
/** Position in the ring of the start of the request */
u32 head;
@@ -247,30 +239,6 @@ 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 inline 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);