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author | Chris Wilson <chris@chris-wilson.co.uk> | 2019-10-04 14:40:00 +0100 |
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committer | Chris Wilson <chris@chris-wilson.co.uk> | 2019-10-04 15:39:12 +0100 |
commit | b1e3177bd1d8f41e2a9cc847e56a96cdc0eefe62 (patch) | |
tree | 9af22565533f12868a015e18e51406d54773e08a /drivers/gpu/drm/i915/gem/i915_gem_context.c | |
parent | 274cbf20fd108fa26d0497282b102e00371210fd (diff) | |
download | linux-b1e3177bd1d8f41e2a9cc847e56a96cdc0eefe62.tar.bz2 |
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/gem/i915_gem_context.c')
-rw-r--r-- | drivers/gpu/drm/i915/gem/i915_gem_context.c | 4 |
1 files changed, 1 insertions, 3 deletions
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c index 4cd7d2ecf1d5..9d85aab68d34 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_context.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c @@ -868,20 +868,18 @@ static int context_barrier_task(struct i915_gem_context *ctx, void (*task)(void *data), void *data) { - struct drm_i915_private *i915 = ctx->i915; struct context_barrier_task *cb; struct i915_gem_engines_iter it; struct intel_context *ce; int err = 0; - lockdep_assert_held(&i915->drm.struct_mutex); GEM_BUG_ON(!task); cb = kmalloc(sizeof(*cb), GFP_KERNEL); if (!cb) return -ENOMEM; - i915_active_init(i915, &cb->base, NULL, cb_retire); + i915_active_init(&cb->base, NULL, cb_retire); err = i915_active_acquire(&cb->base); if (err) { kfree(cb); |