[gnome-remote-desktop] rdp: Add RDP buffer pool

[Jonas Ådahl <jadahl src gnome org>]

commit b39ba2a7a56e9a67811e4377363e239259a05132
Author: Pascal Nowack <Pascal Nowack gmx de>
Date:   Mon Jan 3 09:21:51 2022 +0100

    rdp: Add RDP buffer pool
    
    Allocating buffers on the GPU or registering pixel buffer objects for
    the use on the GPU takes more time and requires more effort than
    allocating a buffer in memory.
    Unregistering such buffers can introduce additional complexity to this
    problem.
    
    To take care of this problem, introduce a buffer recycle mechanism in
    form a buffer pool.
    This buffer pool allocates N buffers by default.
    Instead of allocating a new buffer, when one is needed, the entity that
    needs a new buffer takes a buffer from the pool.
    If all buffers of a buffer pool are used, the buffer pool takes care of
    allocating another buffer in order to handle such situations
    gracefully.
    Instead of deleting a buffer, when it is not needed any more, it will
    be returned to the buffer pool.
    Returning a buffer is a fast action. When a buffer pool resize is
    needed upon returning a buffer, the buffer pool queues a resize using a
    GSource.
    This GSource will then resize the buffer pool on the main thread.

 src/grd-rdp-buffer-pool.c | 273 ++++++++++++++++++++++++++++++++++++++++++++++
 src/grd-rdp-buffer-pool.h |  44 ++++++++
 src/grd-types.h           |   1 +
 src/meson.build           |   2 +
 4 files changed, 320 insertions(+)
---
diff --git a/src/grd-rdp-buffer-pool.c b/src/grd-rdp-buffer-pool.c
new file mode 100644
index 00000000..d59de088
--- /dev/null
+++ b/src/grd-rdp-buffer-pool.c
@@ -0,0 +1,273 @@
+/*
+ * Copyright (C) 2022 Pascal Nowack
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+ * 02111-1307, USA.
+ */
+
+#include "config.h"
+
+#include "grd-rdp-buffer-pool.h"
+
+#include "grd-rdp-buffer.h"
+
+typedef struct _BufferInfo
+{
+  gboolean buffer_taken;
+} BufferInfo;
+
+struct _GrdRdpBufferPool
+{
+  GObject parent;
+
+  gboolean has_buffer_size;
+  uint32_t buffer_width;
+  uint32_t buffer_height;
+  uint32_t buffer_stride;
+
+  GSource *resize_pool_source;
+  uint32_t minimum_pool_size;
+
+  GMutex pool_mutex;
+  GHashTable *buffer_table;
+  uint32_t buffers_taken;
+};
+
+G_DEFINE_TYPE (GrdRdpBufferPool, grd_rdp_buffer_pool, G_TYPE_OBJECT)
+
+static void
+add_buffer_to_pool (GrdRdpBufferPool *buffer_pool)
+{
+  GrdRdpBuffer *buffer;
+  BufferInfo *buffer_info;
+
+  buffer = grd_rdp_buffer_new ();
+  buffer_info = g_new0 (BufferInfo, 1);
+
+  if (buffer_pool->has_buffer_size)
+    {
+      grd_rdp_buffer_resize (buffer,
+                             buffer_pool->buffer_width,
+                             buffer_pool->buffer_height,
+                             buffer_pool->buffer_stride);
+    }
+
+  g_hash_table_insert (buffer_pool->buffer_table, buffer, buffer_info);
+}
+
+void
+grd_rdp_buffer_pool_resize_buffers (GrdRdpBufferPool *buffer_pool,
+                                    uint32_t          buffer_width,
+                                    uint32_t          buffer_height,
+                                    uint32_t          buffer_stride)
+{
+  GHashTableIter iter;
+  GrdRdpBuffer *buffer;
+  BufferInfo *buffer_info;
+
+  g_mutex_lock (&buffer_pool->pool_mutex);
+  g_assert (buffer_pool->buffers_taken == 0);
+
+  buffer_pool->buffer_width = buffer_width;
+  buffer_pool->buffer_height = buffer_height;
+  buffer_pool->buffer_stride = buffer_stride;
+  buffer_pool->has_buffer_size = TRUE;
+
+  g_hash_table_iter_init (&iter, buffer_pool->buffer_table);
+  while (g_hash_table_iter_next (&iter, (gpointer *) &buffer,
+                                        (gpointer *) &buffer_info))
+    {
+      g_assert (!buffer_info->buffer_taken);
+      grd_rdp_buffer_resize (buffer, buffer_width, buffer_height, buffer_stride);
+    }
+  g_mutex_unlock (&buffer_pool->pool_mutex);
+}
+
+GrdRdpBuffer *
+grd_rdp_buffer_pool_acquire (GrdRdpBufferPool *buffer_pool)
+{
+  GHashTableIter iter;
+  GrdRdpBuffer *buffer;
+  BufferInfo *buffer_info;
+
+  g_mutex_lock (&buffer_pool->pool_mutex);
+  if (g_hash_table_size (buffer_pool->buffer_table) <= buffer_pool->buffers_taken)
+    add_buffer_to_pool (buffer_pool);
+
+  g_hash_table_iter_init (&iter, buffer_pool->buffer_table);
+  while (g_hash_table_iter_next (&iter, (gpointer *) &buffer,
+                                        (gpointer *) &buffer_info))
+    {
+      if (!buffer_info->buffer_taken)
+        break;
+    }
+
+  buffer_info->buffer_taken = TRUE;
+  ++buffer_pool->buffers_taken;
+  g_mutex_unlock (&buffer_pool->pool_mutex);
+
+  return buffer;
+}
+
+static gboolean
+should_resize_buffer_pool (GrdRdpBufferPool *buffer_pool)
+{
+  uint32_t buffers_taken = buffer_pool->buffers_taken;
+  uint32_t minimum_size = buffer_pool->minimum_pool_size;
+  uint32_t current_pool_size;
+
+  current_pool_size = g_hash_table_size (buffer_pool->buffer_table);
+
+  if (current_pool_size > minimum_size &&
+      current_pool_size > buffers_taken)
+    return TRUE;
+
+  return FALSE;
+}
+
+void
+grd_rdp_buffer_pool_release_buffer (GrdRdpBufferPool *buffer_pool,
+                                    GrdRdpBuffer     *buffer)
+{
+  BufferInfo *buffer_info;
+  gboolean queue_pool_resize;
+
+  g_mutex_lock (&buffer_pool->pool_mutex);
+  if (!g_hash_table_lookup_extended (buffer_pool->buffer_table, buffer,
+                                     NULL, (gpointer *) &buffer_info))
+    g_assert_not_reached ();
+
+  g_assert (buffer_info->buffer_taken);
+
+  buffer_info->buffer_taken = FALSE;
+  --buffer_pool->buffers_taken;
+
+  queue_pool_resize = should_resize_buffer_pool (buffer_pool);
+  g_mutex_unlock (&buffer_pool->pool_mutex);
+
+  if (queue_pool_resize)
+    g_source_set_ready_time (buffer_pool->resize_pool_source, 0);
+}
+
+static gboolean
+resize_buffer_pool (gpointer user_data)
+{
+  GrdRdpBufferPool *buffer_pool = user_data;
+  GHashTableIter iter;
+  BufferInfo *buffer_info;
+
+  g_mutex_lock (&buffer_pool->pool_mutex);
+  g_hash_table_iter_init (&iter, buffer_pool->buffer_table);
+  while (should_resize_buffer_pool (buffer_pool) &&
+         g_hash_table_iter_next (&iter, NULL, (gpointer *) &buffer_info))
+    {
+      if (!buffer_info->buffer_taken)
+        g_hash_table_iter_remove (&iter);
+    }
+  g_mutex_unlock (&buffer_pool->pool_mutex);
+
+  return G_SOURCE_CONTINUE;
+}
+
+static gboolean
+resize_pool_source_dispatch (GSource     *source,
+                             GSourceFunc  callback,
+                             gpointer     user_data)
+{
+  g_source_set_ready_time (source, -1);
+
+  return callback (user_data);
+}
+
+static GSourceFuncs resize_pool_source_funcs =
+{
+  .dispatch = resize_pool_source_dispatch,
+};
+
+static void
+fill_buffer_pool (GrdRdpBufferPool *buffer_pool)
+{
+  uint32_t minimum_size = buffer_pool->minimum_pool_size;
+
+  while (g_hash_table_size (buffer_pool->buffer_table) < minimum_size)
+    add_buffer_to_pool (buffer_pool);
+}
+
+GrdRdpBufferPool *
+grd_rdp_buffer_pool_new (uint32_t minimum_size)
+{
+  GrdRdpBufferPool *buffer_pool;
+
+  buffer_pool = g_object_new (GRD_TYPE_RDP_BUFFER_POOL, NULL);
+  buffer_pool->minimum_pool_size = minimum_size;
+
+  buffer_pool->resize_pool_source = g_source_new (&resize_pool_source_funcs,
+                                                 sizeof (GSource));
+  g_source_set_callback (buffer_pool->resize_pool_source,
+                         resize_buffer_pool, buffer_pool, NULL);
+  g_source_set_ready_time (buffer_pool->resize_pool_source, -1);
+  g_source_attach (buffer_pool->resize_pool_source, NULL);
+
+  fill_buffer_pool (buffer_pool);
+
+  return buffer_pool;
+}
+
+static void
+grd_rdp_buffer_pool_dispose (GObject *object)
+{
+  GrdRdpBufferPool *buffer_pool = GRD_RDP_BUFFER_POOL (object);
+
+  if (buffer_pool->resize_pool_source)
+    {
+      g_source_destroy (buffer_pool->resize_pool_source);
+      g_clear_pointer (&buffer_pool->resize_pool_source, g_source_unref);
+    }
+
+  g_assert (buffer_pool->buffers_taken == 0);
+
+  G_OBJECT_CLASS (grd_rdp_buffer_pool_parent_class)->dispose (object);
+}
+
+static void
+grd_rdp_buffer_pool_finalize (GObject *object)
+{
+  GrdRdpBufferPool *buffer_pool = GRD_RDP_BUFFER_POOL (object);
+
+  g_mutex_clear (&buffer_pool->pool_mutex);
+
+  g_clear_pointer (&buffer_pool->buffer_table, g_hash_table_unref);
+
+  G_OBJECT_CLASS (grd_rdp_buffer_pool_parent_class)->finalize (object);
+}
+
+static void
+grd_rdp_buffer_pool_init (GrdRdpBufferPool *buffer_pool)
+{
+  buffer_pool->buffer_table = g_hash_table_new_full (NULL, NULL,
+                                                     (GDestroyNotify) grd_rdp_buffer_free,
+                                                     g_free);
+
+  g_mutex_init (&buffer_pool->pool_mutex);
+}
+
+static void
+grd_rdp_buffer_pool_class_init (GrdRdpBufferPoolClass *klass)
+{
+  GObjectClass *object_class = G_OBJECT_CLASS (klass);
+
+  object_class->dispose = grd_rdp_buffer_pool_dispose;
+  object_class->finalize = grd_rdp_buffer_pool_finalize;
+}
diff --git a/src/grd-rdp-buffer-pool.h b/src/grd-rdp-buffer-pool.h
new file mode 100644
index 00000000..121c86f5
--- /dev/null
+++ b/src/grd-rdp-buffer-pool.h
@@ -0,0 +1,44 @@
+/*
+ * Copyright (C) 2022 Pascal Nowack
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+ * 02111-1307, USA.
+ */
+
+#ifndef GRD_RDP_BUFFER_POOL_H
+#define GRD_RDP_BUFFER_POOL_H
+
+#include <glib-object.h>
+#include <stdint.h>
+
+#include "grd-types.h"
+
+#define GRD_TYPE_RDP_BUFFER_POOL (grd_rdp_buffer_pool_get_type ())
+G_DECLARE_FINAL_TYPE (GrdRdpBufferPool, grd_rdp_buffer_pool,
+                      GRD, RDP_BUFFER_POOL, GObject)
+
+GrdRdpBufferPool *grd_rdp_buffer_pool_new (uint32_t minimum_size);
+
+void grd_rdp_buffer_pool_resize_buffers (GrdRdpBufferPool *buffer_pool,
+                                         uint32_t          buffer_width,
+                                         uint32_t          buffer_height,
+                                         uint32_t          buffer_stride);
+
+GrdRdpBuffer *grd_rdp_buffer_pool_acquire (GrdRdpBufferPool *buffer_pool);
+
+void grd_rdp_buffer_pool_release_buffer (GrdRdpBufferPool *buffer_pool,
+                                         GrdRdpBuffer     *buffer);
+
+#endif /* GRD_RDP_BUFFER_POOL_H */
diff --git a/src/grd-types.h b/src/grd-types.h
index ec039771..abd922e1 100644
--- a/src/grd-types.h
+++ b/src/grd-types.h
@@ -31,6 +31,7 @@ typedef struct _GrdEglThread GrdEglThread;
 typedef struct _GrdHwAccelNvidia GrdHwAccelNvidia;
 typedef struct _GrdRdpEventQueue GrdRdpEventQueue;
 typedef struct _GrdRdpBuffer GrdRdpBuffer;
+typedef struct _GrdRdpBufferPool GrdRdpBufferPool;
 typedef struct _GrdRdpGfxFrameLog GrdRdpGfxFrameLog;
 typedef struct _GrdRdpGfxSurface GrdRdpGfxSurface;
 typedef struct _GrdRdpGraphicsPipeline GrdRdpGraphicsPipeline;
diff --git a/src/meson.build b/src/meson.build
index a24c239c..f8699eaf 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -47,6 +47,8 @@ if have_rdp
     'grd-clipboard-rdp.h',
     'grd-rdp-buffer.c',
     'grd-rdp-buffer.h',
+    'grd-rdp-buffer-pool.c',
+    'grd-rdp-buffer-pool.h',
     'grd-rdp-event-queue.c',
     'grd-rdp-event-queue.h',
     'grd-rdp-frame-info.h',