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drm/i915: Use atomic for dev_priv->mm.bsd_engine_dispatch_index 

Use atomic type and operands for dev_priv->mm.bsd_engine_dispatch_index
to avoid one struct_mutex locking scenario.

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Zhao Yakui <yakui.zhao@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/1472731101-21982-1-git-send-email-joonas.lahtinen@linux.intel.com
This commit is contained in:
Joonas Lahtinen 2016-09-01 14:58:21 +03:00
parent 5423adf1d4
commit 6f63340284
3 changed files with 6 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
drivers/gpu/drm/i915/i915_drv.h
View File

@ -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;

2
drivers/gpu/drm/i915/i915_gem.c
View File

@ -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);
}

10
drivers/gpu/drm/i915/i915_gem_execbuffer.c
View File

@ -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;
}