From c5cf9a9147ff6fc9f87251a8f8a5b6ac8b8bdcdc Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Wed, 17 May 2017 13:10:04 +0100
Subject: [PATCH] drm/i915: Create a kmem_cache to allocate struct i915_priolist from
Git-commit: c5cf9a9147ff6fc9f87251a8f8a5b6ac8b8bdcdc
Patch-mainline: v4.13-rc1
References: FATE#322643 bsc#1055900

The i915_priolist are allocated within an atomic context on a path where
we wish to minimise latency. If we use a dedicated kmem_cache, we have
the advantage of a local freelist from which to service new requests
that should keep the latency impact of an allocation small. Though
currently we expect the majority of requests to be at default priority
(and so hit the preallocate priolist), once userspace starts using
priorities they are likely to use many fine grained policies improving
the utilisation of a private slab.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170517121007.27224-9-chris@chris-wilson.co.uk
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/gpu/drm/i915/i915_drv.h                  |    1 +
 drivers/gpu/drm/i915/i915_gem.c                  |    9 ++++++++-
 drivers/gpu/drm/i915/i915_guc_submission.c       |    2 +-
 drivers/gpu/drm/i915/intel_lrc.c                 |    4 ++--
 drivers/gpu/drm/i915/selftests/mock_gem_device.c |    9 ++++++++-
 5 files changed, 20 insertions(+), 5 deletions(-)

--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2028,6 +2028,7 @@ struct drm_i915_private {
 	struct kmem_cache *vmas;
 	struct kmem_cache *requests;
 	struct kmem_cache *dependencies;
+	struct kmem_cache *priorities;
 
 	const struct intel_device_info info;
 
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -4891,12 +4891,16 @@ i915_gem_load_init(struct drm_i915_priva
 	if (!dev_priv->dependencies)
 		goto err_requests;
 
+	dev_priv->priorities = KMEM_CACHE(i915_priolist, SLAB_HWCACHE_ALIGN);
+	if (!dev_priv->priorities)
+		goto err_dependencies;
+
 	mutex_lock(&dev_priv->drm.struct_mutex);
 	INIT_LIST_HEAD(&dev_priv->gt.timelines);
 	err = i915_gem_timeline_init__global(dev_priv);
 	mutex_unlock(&dev_priv->drm.struct_mutex);
 	if (err)
-		goto err_dependencies;
+		goto err_priorities;
 
 	INIT_LIST_HEAD(&dev_priv->context_list);
 	INIT_WORK(&dev_priv->mm.free_work, __i915_gem_free_work);
@@ -4920,6 +4924,8 @@ i915_gem_load_init(struct drm_i915_priva
 
 	return 0;
 
+err_priorities:
+	kmem_cache_destroy(dev_priv->priorities);
 err_dependencies:
 	kmem_cache_destroy(dev_priv->dependencies);
 err_requests:
@@ -4943,6 +4949,7 @@ void i915_gem_load_cleanup(struct drm_i9
 	WARN_ON(!list_empty(&dev_priv->gt.timelines));
 	mutex_unlock(&dev_priv->drm.struct_mutex);
 
+	kmem_cache_destroy(dev_priv->priorities);
 	kmem_cache_destroy(dev_priv->dependencies);
 	kmem_cache_destroy(dev_priv->requests);
 	kmem_cache_destroy(dev_priv->vmas);
--- a/drivers/gpu/drm/i915/i915_guc_submission.c
+++ b/drivers/gpu/drm/i915/i915_guc_submission.c
@@ -704,7 +704,7 @@ static bool i915_guc_dequeue(struct inte
 		rb_erase(&p->node, &engine->execlist_queue);
 		INIT_LIST_HEAD(&p->requests);
 		if (p->priority != I915_PRIORITY_NORMAL)
-			kfree(p);
+			kmem_cache_free(engine->i915->priorities, p);
 	}
 done:
 	engine->execlist_first = rb;
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -499,7 +499,7 @@ static void execlists_dequeue(struct int
 		rb_erase(&p->node, &engine->execlist_queue);
 		INIT_LIST_HEAD(&p->requests);
 		if (p->priority != I915_PRIORITY_NORMAL)
-			kfree(p);
+			kmem_cache_free(engine->i915->priorities, p);
 	}
 done:
 	engine->execlist_first = rb;
@@ -661,7 +661,7 @@ find_priolist:
 	if (prio == I915_PRIORITY_NORMAL) {
 		p = &engine->default_priolist;
 	} else {
-		p = kmalloc(sizeof(*p), GFP_ATOMIC);
+		p = kmem_cache_alloc(engine->i915->priorities, GFP_ATOMIC);
 		/* Convert an allocation failure to a priority bump */
 		if (unlikely(!p)) {
 			prio = I915_PRIORITY_NORMAL; /* recurses just once */
--- a/drivers/gpu/drm/i915/selftests/mock_gem_device.c
+++ b/drivers/gpu/drm/i915/selftests/mock_gem_device.c
@@ -74,6 +74,7 @@ static void mock_device_release(struct d
 
 	destroy_workqueue(i915->wq);
 
+	kmem_cache_destroy(i915->priorities);
 	kmem_cache_destroy(i915->dependencies);
 	kmem_cache_destroy(i915->requests);
 	kmem_cache_destroy(i915->vmas);
@@ -186,12 +187,16 @@ struct drm_i915_private *mock_gem_device
 	if (!i915->dependencies)
 		goto err_requests;
 
+	i915->priorities = KMEM_CACHE(i915_priolist, SLAB_HWCACHE_ALIGN);
+	if (!i915->priorities)
+		goto err_dependencies;
+
 	mutex_lock(&i915->drm.struct_mutex);
 	INIT_LIST_HEAD(&i915->gt.timelines);
 	err = i915_gem_timeline_init__global(i915);
 	if (err) {
 		mutex_unlock(&i915->drm.struct_mutex);
-		goto err_dependencies;
+		goto err_priorities;
 	}
 
 	mock_init_ggtt(i915);
@@ -211,6 +216,8 @@ struct drm_i915_private *mock_gem_device
 err_engine:
 	for_each_engine(engine, i915, id)
 		mock_engine_free(engine);
+err_priorities:
+	kmem_cache_destroy(i915->priorities);
 err_dependencies:
 	kmem_cache_destroy(i915->dependencies);
 err_requests: