diff options
| author | Chris Wilson <chris@chris-wilson.co.uk> | 2020-07-31 09:50:14 +0100 |
|---|---|---|
| committer | Joonas Lahtinen <joonas.lahtinen@linux.intel.com> | 2020-09-03 15:35:25 +0300 |
| commit | 0e69f4622e6aa5d1147d15e1d7ff4bba70496c8a (patch) | |
| tree | 7ba089e2c6e79c3af47e083811cf6ceae4dec2ad | |
| parent | e17a6ce709c2a54ffae61c3a556a429365d5968d (diff) | |
drm/i915: Reduce locking around i915_active_acquire_preallocate_barrier()
As the conversion between idle-barrier and full i915_active_fence is
already serialised by explicit memory barriers, we can reduce the
spinlock in i915_active_acquire_preallocate_barrier() for finding an
idle-barrier to reuse to an RCU read lock to ensure the fence remains
valid, only taking the spinlock for the update of the rbtree itself.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Thomas Hellström <thomas.hellstrom@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200731085015.32368-6-chris@chris-wilson.co.uk
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
| -rw-r--r-- | drivers/gpu/drm/i915/i915_active.c | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/drivers/gpu/drm/i915/i915_active.c b/drivers/gpu/drm/i915/i915_active.c index 89c34a69a2ea..b0a6522be3d1 100644 --- a/drivers/gpu/drm/i915/i915_active.c +++ b/drivers/gpu/drm/i915/i915_active.c @@ -807,7 +807,6 @@ static struct active_node *reuse_idle_barrier(struct i915_active *ref, u64 idx) if (RB_EMPTY_ROOT(&ref->tree)) return NULL; - spin_lock_irq(&ref->tree_lock); GEM_BUG_ON(i915_active_is_idle(ref)); /* @@ -833,9 +832,9 @@ static struct active_node *reuse_idle_barrier(struct i915_active *ref, u64 idx) prev = p; if (node->timeline < idx) - p = p->rb_right; + p = READ_ONCE(p->rb_right); else - p = p->rb_left; + p = READ_ONCE(p->rb_left); } /* @@ -872,11 +871,10 @@ static struct active_node *reuse_idle_barrier(struct i915_active *ref, u64 idx) goto match; } - spin_unlock_irq(&ref->tree_lock); - return NULL; match: + spin_lock_irq(&ref->tree_lock); rb_erase(p, &ref->tree); /* Hide from waits and sibling allocations */ if (p == &ref->cache->node) WRITE_ONCE(ref->cache, NULL); @@ -910,7 +908,9 @@ int i915_active_acquire_preallocate_barrier(struct i915_active *ref, struct llist_node *prev = first; struct active_node *node; + rcu_read_lock(); node = reuse_idle_barrier(ref, idx); + rcu_read_unlock(); if (!node) { node = kmem_cache_alloc(global.slab_cache, GFP_KERNEL); if (!node) |