Use atomic type and operands for dev_priv->mm.bsd_engine_dispatch_index
to avoid one struct_mutex locking scenario.
Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Imre Deak <imre.deak@xxxxxxxxx>
Cc: Zhao Yakui <yakui.zhao@xxxxxxxxx>
Cc: Daniel Vetter <daniel.vetter@xxxxxxxx>
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/i915_drv.h | 2 +-
drivers/gpu/drm/i915/i915_gem.c | 2 ++
drivers/gpu/drm/i915/i915_gem_execbuffer.c | 10 +++-------
3 files changed, 6 insertions(+), 8 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index c413587..43d5298 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1338,7 +1338,7 @@ struct i915_gem_mm {
bool interruptible;
/* the indicator for dispatch video commands on two BSD rings */
- unsigned int bsd_engine_dispatch_index;
+ atomic_t bsd_engine_dispatch_index;
/** Bit 6 swizzling required for X tiling */
uint32_t bit_6_swizzle_x;
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index d37b441..2401818 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -4622,6 +4622,8 @@ i915_gem_load_init(struct drm_device *dev)
dev_priv->mm.interruptible = true;
+ atomic_set(&dev_priv->mm.bsd_engine_dispatch_index, 0);
+
spin_lock_init(&dev_priv->fb_tracking.lock);
}
diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
index 57d096a..9432d4c 100644
--- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
@@ -1535,13 +1535,9 @@ gen8_dispatch_bsd_engine(struct drm_i915_private *dev_priv,
struct drm_i915_file_private *file_priv = file->driver_priv;
/* Check whether the file_priv has already selected one ring. */
- if ((int)file_priv->bsd_engine < 0) {
- /* If not, use the ping-pong mechanism to select one. */
- mutex_lock(&dev_priv->drm.struct_mutex);
- file_priv->bsd_engine = dev_priv->mm.bsd_engine_dispatch_index;
- dev_priv->mm.bsd_engine_dispatch_index ^= 1;
- mutex_unlock(&dev_priv->drm.struct_mutex);
- }
+ if ((int)file_priv->bsd_engine < 0)
+ file_priv->bsd_engine = atomic_fetch_xor(1,
+ &dev_priv->mm.bsd_engine_dispatch_index);
return file_priv->bsd_engine;
}
--
2.5.5
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