drm/i915: evict VM instead of everything

When reserving objects during execbuf, it is possible to come across an
object which will not fit given the current fragmentation of the address
space. We do not have any defragment in drm_mm, so the strategy is to
instead evict everything, and reallocate objects.

With the upcoming addition of multiple VMs, there is no point to evict
everything since doing so is overkill for the specific case mentioned
above.

Recommended-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
[danvet: One additional s/evict_everything/evict_vm/ to update a
comment in the code.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 81ba5bbc97fa43939cdb46fb5049297fe4dd38b6..7caf71d52abe678ceecfe9b542ba1741e76e77b2 100644 (file)
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2106,6 +2106,7 @@ int __must_check i915_gem_evict_something(struct drm_device *dev,
                                          unsigned cache_level,
                                          bool mappable,
                                          bool nonblock);
+int i915_gem_evict_vm(struct i915_address_space *vm, bool do_idle);
 int i915_gem_evict_everything(struct drm_device *dev);
 
 /* i915_gem_stolen.c */

diff --git a/drivers/gpu/drm/i915/i915_gem_evict.c b/drivers/gpu/drm/i915/i915_gem_evict.c
index e9033f02f4982dd6eefe5b193d9f78e8a5aed579..3a3981eb30121fd6df7ef3e8b0fa5f1874ae9f0f 100644 (file)
--- a/drivers/gpu/drm/i915/i915_gem_evict.c
+++ b/drivers/gpu/drm/i915/i915_gem_evict.c
@@ -116,7 +116,7 @@ none:
        }
 
        /* We expect the caller to unpin, evict all and try again, or give up.
-        * So calling i915_gem_evict_everything() is unnecessary.
+        * So calling i915_gem_evict_vm() is unnecessary.
         */
        return -ENOSPC;
 
@@ -155,7 +155,22 @@ found:
        return ret;
 }
 
-static int i915_gem_evict_vm(struct i915_address_space *vm, bool do_idle)
+/**
+ * i915_gem_evict_vm - Try to free up VM space
+ *
+ * @vm: Address space to evict from
+ * @do_idle: Boolean directing whether to idle first.
+ *
+ * VM eviction is about freeing up virtual address space. If one wants fine
+ * grained eviction, they should see evict something for more details. In terms
+ * of freeing up actual system memory, this function may not accomplish the
+ * desired result. An object may be shared in multiple address space, and this
+ * function will not assert those objects be freed.
+ *
+ * Using do_idle will result in a more complete eviction because it retires, and
+ * inactivates current BOs.
+ */
+int i915_gem_evict_vm(struct i915_address_space *vm, bool do_idle)
 {
        struct i915_vma *vma, *next;
        int ret;

diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
index c8a01c141644d80e93936d858b21f0ada1fe6f51..ee933572bdc150ce9fe94a8233be3b95aff80544 100644 (file)
--- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
@@ -549,10 +549,16 @@ i915_gem_execbuffer_reserve(struct intel_ring_buffer *ring,
 {
        struct drm_i915_gem_object *obj;
        struct i915_vma *vma;
+       struct i915_address_space *vm;
        struct list_head ordered_vmas;
        bool has_fenced_gpu_access = INTEL_INFO(ring->dev)->gen < 4;
        int retry;
 
+       if (list_empty(vmas))
+               return 0;
+
+       vm = list_first_entry(vmas, struct i915_vma, exec_list)->vm;
+
        INIT_LIST_HEAD(&ordered_vmas);
        while (!list_empty(vmas)) {
                struct drm_i915_gem_exec_object2 *entry;
@@ -641,7 +647,7 @@ err:                /* Decrement pin count for bound objects */
                if (ret != -ENOSPC || retry++)
                        return ret;
 
-               ret = i915_gem_evict_everything(ring->dev);
+               ret = i915_gem_evict_vm(vm, true);
                if (ret)
                        return ret;
        } while (1);