From 6f633402847635817fd5eddb2d0e0a50cd521c1e Mon Sep 17 00:00:00 2001 From: Joonas Lahtinen Date: Thu, 1 Sep 2016 14:58:21 +0300 Subject: [PATCH] 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 Cc: Imre Deak Cc: Zhao Yakui Cc: Daniel Vetter Signed-off-by: Joonas Lahtinen Reviewed-by: Chris Wilson Link: http://patchwork.freedesktop.org/patch/msgid/1472731101-21982-1-git-send-email-joonas.lahtinen@linux.intel.com --- 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 c413587895cf..43d5298b821f 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 d37b44126942..2401818171f5 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 57d096aef548..9432d4ce9ffb 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; }