drm/i915: Make request allocation caches global

As kmem_caches share the same properties (size, allocation/free behaviour)
for all potential devices, we can use global caches. While this
potential has worse fragmentation behaviour (one can argue that
different devices would have different activity lifetimes, but you can
also argue that activity is temporal across the system) it is the
default behaviour of the system at large to amalgamate matching caches.

The benefit for us is much reduced pointer dancing along the frequent
allocation paths.

v2: Defer shrinking until after a global grace period for futureproofing
multiple consumers of the slab caches, similar to the current strategy
for avoiding shrinking too early.

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/20190228102035.5857-1-chris@chris-wilson.co.uk

1 files changed, 5 insertions, 29 deletions

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index de8b92da56cf..f6fe10fce0ec 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -42,6 +42,7 @@
 #include "i915_drv.h"
 #include "i915_gem_clflush.h"
 #include "i915_gemfs.h"
+#include "i915_globals.h"
 #include "i915_reset.h"
 #include "i915_trace.h"
 #include "i915_vgpu.h"
@@ -187,6 +188,8 @@ void i915_gem_unpark(struct drm_i915_private *i915)
 	if (unlikely(++i915->gt.epoch == 0)) /* keep 0 as invalid */
 		i915->gt.epoch = 1;
 
+	i915_globals_unpark();
+
 	intel_enable_gt_powersave(i915);
 	i915_update_gfx_val(i915);
 	if (INTEL_GEN(i915) >= 6)
@@ -2892,12 +2895,11 @@ static void shrink_caches(struct drm_i915_private *i915)
 	 * filled slabs to prioritise allocating from the mostly full slabs,
 	 * with the aim of reducing fragmentation.
 	 */
-	kmem_cache_shrink(i915->priorities);
-	kmem_cache_shrink(i915->dependencies);
-	kmem_cache_shrink(i915->requests);
 	kmem_cache_shrink(i915->luts);
 	kmem_cache_shrink(i915->vmas);
 	kmem_cache_shrink(i915->objects);
+
+	i915_globals_park();
 }
 
 struct sleep_rcu_work {
@@ -5237,23 +5239,6 @@ int i915_gem_init_early(struct drm_i915_private *dev_priv)
 	if (!dev_priv->luts)
 		goto err_vmas;
 
-	dev_priv->requests = KMEM_CACHE(i915_request,
-					SLAB_HWCACHE_ALIGN |
-					SLAB_RECLAIM_ACCOUNT |
-					SLAB_TYPESAFE_BY_RCU);
-	if (!dev_priv->requests)
-		goto err_luts;
-
-	dev_priv->dependencies = KMEM_CACHE(i915_dependency,
-					    SLAB_HWCACHE_ALIGN |
-					    SLAB_RECLAIM_ACCOUNT);
-	if (!dev_priv->dependencies)
-		goto err_requests;
-
-	dev_priv->priorities = KMEM_CACHE(i915_priolist, SLAB_HWCACHE_ALIGN);
-	if (!dev_priv->priorities)
-		goto err_dependencies;
-
 	INIT_LIST_HEAD(&dev_priv->gt.active_rings);
 	INIT_LIST_HEAD(&dev_priv->gt.closed_vma);
 
@@ -5278,12 +5263,6 @@ int i915_gem_init_early(struct drm_i915_private *dev_priv)
 
 	return 0;
 
-err_dependencies:
-	kmem_cache_destroy(dev_priv->dependencies);
-err_requests:
-	kmem_cache_destroy(dev_priv->requests);
-err_luts:
-	kmem_cache_destroy(dev_priv->luts);
 err_vmas:
 	kmem_cache_destroy(dev_priv->vmas);
 err_objects:
@@ -5301,9 +5280,6 @@ void i915_gem_cleanup_early(struct drm_i915_private *dev_priv)
 
 	cleanup_srcu_struct(&dev_priv->gpu_error.reset_backoff_srcu);
 
-	kmem_cache_destroy(dev_priv->priorities);
-	kmem_cache_destroy(dev_priv->dependencies);
-	kmem_cache_destroy(dev_priv->requests);
 	kmem_cache_destroy(dev_priv->luts);
 	kmem_cache_destroy(dev_priv->vmas);
 	kmem_cache_destroy(dev_priv->objects);