drm/i915/gt: Move the batch buffer pool from the engine to the gt

Since the introduction of 'soft-rc6', we aim to park the device quickly
and that results in frequent idling of the whole device. Currently upon
idling we free the batch buffer pool, and so this renders the cache
ineffective for many workloads. If we want to have an effective cache of
recently allocated buffers available for reuse, we need to decouple that
cache from the engine powermanagement and make it timer based. As there
is no reason then to keep it within the engine (where it once made
retirement order easier to track), we can move it up the hierarchy to the
owner of the memory allocations.

v2: Hook up to debugfs/drop_caches to clear the cache on demand.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200430111819.10262-2-chris@chris-wilson.co.uk

1 files changed, 37 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/gt/intel_gt_buffer_pool.h b/drivers/gpu/drm/i915/gt/intel_gt_buffer_pool.h
new file mode 100644
index 000000000000..42cbac003e8a
--- /dev/null
+++ b/drivers/gpu/drm/i915/gt/intel_gt_buffer_pool.h
@@ -0,0 +1,37 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Copyright © 2014-2018 Intel Corporation
+ */
+
+#ifndef INTEL_GT_BUFFER_POOL_H
+#define INTEL_GT_BUFFER_POOL_H
+
+#include <linux/types.h>
+
+#include "i915_active.h"
+#include "intel_gt_buffer_pool_types.h"
+
+struct intel_gt;
+struct i915_request;
+
+struct intel_gt_buffer_pool_node *
+intel_gt_get_buffer_pool(struct intel_gt *gt, size_t size);
+
+static inline int
+intel_gt_buffer_pool_mark_active(struct intel_gt_buffer_pool_node *node,
+				 struct i915_request *rq)
+{
+	return i915_active_add_request(&node->active, rq);
+}
+
+static inline void
+intel_gt_buffer_pool_put(struct intel_gt_buffer_pool_node *node)
+{
+	i915_active_release(&node->active);
+}
+
+void intel_gt_init_buffer_pool(struct intel_gt *gt);
+void intel_gt_flush_buffer_pool(struct intel_gt *gt);
+void intel_gt_fini_buffer_pool(struct intel_gt *gt);
+
+#endif /* INTEL_GT_BUFFER_POOL_H */