linux/drivers/gpu/drm/i915/i915_timeline.c
Chris Wilson a89d1f921c drm/i915: Split i915_gem_timeline into individual timelines
We need to move to a more flexible timeline that doesn't assume one
fence context per engine, and so allow for a single timeline to be used
across a combination of engines. This means that preallocating a fence
context per engine is now a hindrance, and so we want to introduce the
singular timeline. From the code perspective, this has the notable
advantage of clearing up a lot of mirky semantics and some clumsy
pointer chasing.

By splitting the timeline up into a single entity rather than an array
of per-engine timelines, we can realise the goal of the previous patch
of tracking the timeline alongside the ring.

v2: Tweak wait_for_idle to stop the compiling thinking that ret may be
uninitialised.

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/20180502163839.3248-2-chris@chris-wilson.co.uk
2018-05-02 23:57:18 +01:00

106 lines
2.6 KiB
C

/*
* SPDX-License-Identifier: MIT
*
* Copyright © 2016-2018 Intel Corporation
*/
#include "i915_drv.h"
#include "i915_timeline.h"
#include "i915_syncmap.h"
void i915_timeline_init(struct drm_i915_private *i915,
struct i915_timeline *timeline,
const char *name)
{
lockdep_assert_held(&i915->drm.struct_mutex);
/*
* Ideally we want a set of engines on a single leaf as we expect
* to mostly be tracking synchronisation between engines. It is not
* a huge issue if this is not the case, but we may want to mitigate
* any page crossing penalties if they become an issue.
*/
BUILD_BUG_ON(KSYNCMAP < I915_NUM_ENGINES);
timeline->name = name;
list_add(&timeline->link, &i915->gt.timelines);
/* Called during early_init before we know how many engines there are */
timeline->fence_context = dma_fence_context_alloc(1);
spin_lock_init(&timeline->lock);
init_request_active(&timeline->last_request, NULL);
INIT_LIST_HEAD(&timeline->requests);
i915_syncmap_init(&timeline->sync);
}
/**
* i915_timelines_park - called when the driver idles
* @i915: the drm_i915_private device
*
* When the driver is completely idle, we know that all of our sync points
* have been signaled and our tracking is then entirely redundant. Any request
* to wait upon an older sync point will be completed instantly as we know
* the fence is signaled and therefore we will not even look them up in the
* sync point map.
*/
void i915_timelines_park(struct drm_i915_private *i915)
{
struct i915_timeline *timeline;
lockdep_assert_held(&i915->drm.struct_mutex);
list_for_each_entry(timeline, &i915->gt.timelines, link) {
/*
* All known fences are completed so we can scrap
* the current sync point tracking and start afresh,
* any attempt to wait upon a previous sync point
* will be skipped as the fence was signaled.
*/
i915_syncmap_free(&timeline->sync);
}
}
void i915_timeline_fini(struct i915_timeline *timeline)
{
GEM_BUG_ON(!list_empty(&timeline->requests));
i915_syncmap_free(&timeline->sync);
list_del(&timeline->link);
}
struct i915_timeline *
i915_timeline_create(struct drm_i915_private *i915, const char *name)
{
struct i915_timeline *timeline;
timeline = kzalloc(sizeof(*timeline), GFP_KERNEL);
if (!timeline)
return ERR_PTR(-ENOMEM);
i915_timeline_init(i915, timeline, name);
kref_init(&timeline->kref);
return timeline;
}
void __i915_timeline_free(struct kref *kref)
{
struct i915_timeline *timeline =
container_of(kref, typeof(*timeline), kref);
i915_timeline_fini(timeline);
kfree(timeline);
}
#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
#include "selftests/mock_timeline.c"
#include "selftests/i915_timeline.c"
#endif