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author | Chris Wilson <chris@chris-wilson.co.uk> | 2019-10-04 16:40:00 +0300 |
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committer | Chris Wilson <chris@chris-wilson.co.uk> | 2019-10-04 17:39:12 +0300 |
commit | b1e3177bd1d8f41e2a9cc847e56a96cdc0eefe62 (patch) | |
tree | 9af22565533f12868a015e18e51406d54773e08a /drivers/gpu/drm/i915/i915_vma.c | |
parent | 274cbf20fd108fa26d0497282b102e00371210fd (diff) | |
download | linux-b1e3177bd1d8f41e2a9cc847e56a96cdc0eefe62.tar.xz |
drm/i915: Coordinate i915_active with its own mutex
Forgo the struct_mutex serialisation for i915_active, and interpose its
own mutex handling for active/retire.
This is a multi-layered sleight-of-hand. First, we had to ensure that no
active/retire callbacks accidentally inverted the mutex ordering rules,
nor assumed that they were themselves serialised by struct_mutex. More
challenging though, is the rule over updating elements of the active
rbtree. Instead of the whole i915_active now being serialised by
struct_mutex, allocations/rotations of the tree are serialised by the
i915_active.mutex and individual nodes are serialised by the caller
using the i915_timeline.mutex (we need to use nested spinlocks to
interact with the dma_fence callback lists).
The pain point here is that instead of a single mutex around execbuf, we
now have to take a mutex for active tracker (one for each vma, context,
etc) and a couple of spinlocks for each fence update. The improvement in
fine grained locking allowing for multiple concurrent clients
(eventually!) should be worth it in typical loads.
v2: Add some comments that barely elucidate anything :(
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/20191004134015.13204-6-chris@chris-wilson.co.uk
Diffstat (limited to 'drivers/gpu/drm/i915/i915_vma.c')
-rw-r--r-- | drivers/gpu/drm/i915/i915_vma.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c index e191247c7c5f..9fdcd4e2c799 100644 --- a/drivers/gpu/drm/i915/i915_vma.c +++ b/drivers/gpu/drm/i915/i915_vma.c @@ -120,8 +120,7 @@ vma_create(struct drm_i915_gem_object *obj, vma->size = obj->base.size; vma->display_alignment = I915_GTT_MIN_ALIGNMENT; - i915_active_init(vm->i915, &vma->active, - __i915_vma_active, __i915_vma_retire); + i915_active_init(&vma->active, __i915_vma_active, __i915_vma_retire); /* Declare ourselves safe for use inside shrinkers */ if (IS_ENABLED(CONFIG_LOCKDEP)) { @@ -1148,6 +1147,7 @@ int __i915_vma_unbind(struct i915_vma *vma) if (ret) return ret; + GEM_BUG_ON(i915_vma_is_active(vma)); if (i915_vma_is_pinned(vma)) { vma_print_allocator(vma, "is pinned"); return -EBUSY; |