#include "intel_drv.h"
#include "i915_trace.h"
-static bool ggtt_is_idle(struct drm_i915_private *dev_priv)
+static bool ggtt_is_idle(struct drm_i915_private *i915)
{
- struct i915_ggtt *ggtt = &dev_priv->ggtt;
- struct intel_engine_cs *engine;
- enum intel_engine_id id;
+ struct intel_engine_cs *engine;
+ enum intel_engine_id id;
- for_each_engine(engine, dev_priv, id) {
- struct intel_timeline *tl;
+ if (i915->gt.active_requests)
+ return false;
- tl = &ggtt->base.timeline.engine[engine->id];
- if (i915_gem_active_isset(&tl->last_request))
- return false;
- }
+ for_each_engine(engine, i915, id) {
+ if (engine->last_retired_context != i915->kernel_context)
+ return false;
+ }
- return true;
+ return true;
}
static int ggtt_flush(struct drm_i915_private *i915)
min_size, alignment, cache_level,
start, end, mode);
- /* Retire before we search the active list. Although we have
+ /*
+ * Retire before we search the active list. Although we have
* reasonable accuracy in our retirement lists, we may have
* a stray pin (preventing eviction) that can only be resolved by
* retiring.
BUG_ON(ret);
}
- /* Can we unpin some objects such as idle hw contents,
+ /*
+ * Can we unpin some objects such as idle hw contents,
* or pending flips? But since only the GGTT has global entries
* such as scanouts, rinbuffers and contexts, we can skip the
* purge when inspecting per-process local address spaces.
if (!i915_is_ggtt(vm) || flags & PIN_NONBLOCK)
return -ENOSPC;
- if (ggtt_is_idle(dev_priv)) {
- /* If we still have pending pageflip completions, drop
- * back to userspace to give our workqueues time to
- * acquire our locks and unpin the old scanouts.
- */
- return intel_has_pending_fb_unpin(dev_priv) ? -EAGAIN : -ENOSPC;
- }
+ /*
+ * Not everything in the GGTT is tracked via VMA using
+ * i915_vma_move_to_active(), otherwise we could evict as required
+ * with minimal stalling. Instead we are forced to idle the GPU and
+ * explicitly retire outstanding requests which will then remove
+ * the pinning for active objects such as contexts and ring,
+ * enabling us to evict them on the next iteration.
+ *
+ * To ensure that all user contexts are evictable, we perform
+ * a switch to the perma-pinned kernel context. This all also gives
+ * us a termination condition, when the last retired context is
+ * the kernel's there is no more we can evict.
+ */
+ if (!ggtt_is_idle(dev_priv)) {
+ ret = ggtt_flush(dev_priv);
+ if (ret)
+ return ret;
- ret = ggtt_flush(dev_priv);
- if (ret)
- return ret;
+ goto search_again;
+ }
- goto search_again;
+ /*
+ * If we still have pending pageflip completions, drop
+ * back to userspace to give our workqueues time to
+ * acquire our locks and unpin the old scanouts.
+ */
+ return intel_has_pending_fb_unpin(dev_priv) ? -EAGAIN : -ENOSPC;
found:
/* drm_mm doesn't allow any other other operations while