gallium/pb_cache: add a copy of cache bufmgr independent of pb_manager

This simplified (basically duplicated) version of pb_cache_manager will
allow removing some ugly hacks from radeon and amdgpu winsyses and
flatten simplify their design.

The difference is that winsyses must manually add buffers to the cache
in "destroy" functions and the cache doesn't know about the buffers before
that. The integration is therefore trivial and the impact on the winsys
design is negligible.

Reviewed-by: Nicolai Hähnle <[email protected]>
Reviewed-by: Edward O'Callaghan <[email protected]>
Acked-by: Michel Dänzer <[email protected]>

1 files changed, 286 insertions, 0 deletions

diff --git a/src/gallium/auxiliary/pipebuffer/pb_cache.c b/src/gallium/auxiliary/pipebuffer/pb_cache.c
new file mode 100644
index 00000000000..ebd06b0e030
--- /dev/null
+++ b/src/gallium/auxiliary/pipebuffer/pb_cache.c
@@ -0,0 +1,286 @@
+/**************************************************************************
+ *
+ * Copyright 2007-2008 VMware, Inc.
+ * Copyright 2015 Advanced Micro Devices, Inc.
+ * All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sub license, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial portions
+ * of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
+ * IN NO EVENT SHALL AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR
+ * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ **************************************************************************/
+
+#include "pb_cache.h"
+#include "util/u_memory.h"
+#include "util/u_time.h"
+
+
+/**
+ * Actually destroy the buffer.
+ */
+static void
+destroy_buffer_locked(struct pb_cache_entry *entry)
+{
+   struct pb_cache *mgr = entry->mgr;
+
+   assert(!pipe_is_referenced(&entry->buffer->reference));
+   if (entry->head.next) {
+      LIST_DEL(&entry->head);
+      assert(mgr->num_buffers);
+      --mgr->num_buffers;
+      mgr->cache_size -= entry->buffer->size;
+   }
+   entry->mgr->destroy_buffer(entry->buffer);
+}
+
+/**
+ * Free as many cache buffers from the list head as possible.
+ */
+static void
+release_expired_buffers_locked(struct pb_cache *mgr)
+{
+   struct list_head *curr, *next;
+   struct pb_cache_entry *entry;
+   int64_t now;
+
+   now = os_time_get();
+
+   curr = mgr->cache.next;
+   next = curr->next;
+   while (curr != &mgr->cache) {
+      entry = LIST_ENTRY(struct pb_cache_entry, curr, head);
+
+      if (!os_time_timeout(entry->start, entry->end, now))
+         break;
+
+      destroy_buffer_locked(entry);
+
+      curr = next;
+      next = curr->next;
+   }
+}
+
+/**
+ * Add a buffer to the cache. This is typically done when the buffer is
+ * being released.
+ */
+void
+pb_cache_add_buffer(struct pb_cache_entry *entry)
+{
+   struct pb_cache *mgr = entry->mgr;
+
+   pipe_mutex_lock(mgr->mutex);
+   assert(!pipe_is_referenced(&entry->buffer->reference));
+
+   release_expired_buffers_locked(mgr);
+
+   /* Directly release any buffer that exceeds the limit. */
+   if (mgr->cache_size + entry->buffer->size > mgr->max_cache_size) {
+      entry->mgr->destroy_buffer(entry->buffer);
+      pipe_mutex_unlock(mgr->mutex);
+      return;
+   }
+
+   entry->start = os_time_get();
+   entry->end = entry->start + mgr->usecs;
+   LIST_ADDTAIL(&entry->head, &mgr->cache);
+   ++mgr->num_buffers;
+   mgr->cache_size += entry->buffer->size;
+   pipe_mutex_unlock(mgr->mutex);
+}
+
+/**
+ * \return 1   if compatible and can be reclaimed
+ *         0   if incompatible
+ *        -1   if compatible and can't be reclaimed
+ */
+static int
+pb_cache_is_buffer_compat(struct pb_cache_entry *entry,
+                          pb_size size, unsigned alignment, unsigned usage)
+{
+   struct pb_buffer *buf = entry->buffer;
+
+   if (usage & entry->mgr->bypass_usage)
+      return 0;
+
+   if (buf->size < size)
+      return 0;
+
+   /* be lenient with size */
+   if (buf->size > (unsigned) (entry->mgr->size_factor * size))
+      return 0;
+
+   if (!pb_check_alignment(alignment, buf->alignment))
+      return 0;
+
+   if (!pb_check_usage(usage, buf->usage))
+      return 0;
+
+   return entry->mgr->can_reclaim(buf) ? 1 : -1;
+}
+
+/**
+ * Find a compatible buffer in the cache, return it, and remove it
+ * from the cache.
+ */
+struct pb_buffer *
+pb_cache_reclaim_buffer(struct pb_cache *mgr, pb_size size,
+                        unsigned alignment, unsigned usage)
+{
+   struct pb_cache_entry *entry;
+   struct pb_cache_entry *cur_entry;
+   struct list_head *cur, *next;
+   int64_t now;
+   int ret = 0;
+
+   pipe_mutex_lock(mgr->mutex);
+
+   entry = NULL;
+   cur = mgr->cache.next;
+   next = cur->next;
+
+   /* search in the expired buffers, freeing them in the process */
+   now = os_time_get();
+   while (cur != &mgr->cache) {
+      cur_entry = LIST_ENTRY(struct pb_cache_entry, cur, head);
+
+      if (!entry && (ret = pb_cache_is_buffer_compat(cur_entry, size,
+                                                     alignment, usage) > 0))
+         entry = cur_entry;
+      else if (os_time_timeout(cur_entry->start, cur_entry->end, now))
+         destroy_buffer_locked(cur_entry);
+      else
+         /* This buffer (and all hereafter) are still hot in cache */
+         break;
+
+      /* the buffer is busy (and probably all remaining ones too) */
+      if (ret == -1)
+         break;
+
+      cur = next;
+      next = cur->next;
+   }
+
+   /* keep searching in the hot buffers */
+   if (!entry && ret != -1) {
+      while (cur != &mgr->cache) {
+         cur_entry = LIST_ENTRY(struct pb_cache_entry, cur, head);
+         ret = pb_cache_is_buffer_compat(cur_entry, size, alignment, usage);
+
+         if (ret > 0) {
+            entry = cur_entry;
+            break;
+         }
+         if (ret == -1)
+            break;
+         /* no need to check the timeout here */
+         cur = next;
+         next = cur->next;
+      }
+   }
+
+   /* found a compatible buffer, return it */
+   if (entry) {
+      struct pb_buffer *buf = entry->buffer;
+
+      mgr->cache_size -= buf->size;
+      LIST_DEL(&entry->head);
+      --mgr->num_buffers;
+      pipe_mutex_unlock(mgr->mutex);
+      /* Increase refcount */
+      pipe_reference_init(&buf->reference, 1);
+      return buf;
+   }
+
+   pipe_mutex_unlock(mgr->mutex);
+   return NULL;
+}
+
+/**
+ * Empty the cache. Useful when there is not enough memory.
+ */
+void
+pb_cache_release_all_buffers(struct pb_cache *mgr)
+{
+   struct list_head *curr, *next;
+   struct pb_cache_entry *buf;
+
+   pipe_mutex_lock(mgr->mutex);
+   curr = mgr->cache.next;
+   next = curr->next;
+   while (curr != &mgr->cache) {
+      buf = LIST_ENTRY(struct pb_cache_entry, curr, head);
+      destroy_buffer_locked(buf);
+      curr = next;
+      next = curr->next;
+   }
+   pipe_mutex_unlock(mgr->mutex);
+}
+
+void
+pb_cache_init_entry(struct pb_cache *mgr, struct pb_cache_entry *entry,
+                    struct pb_buffer *buf)
+{
+   memset(entry, 0, sizeof(*entry));
+   entry->buffer = buf;
+   entry->mgr = mgr;
+}
+
+/**
+ * Initialize a caching buffer manager.
+ *
+ * @param mgr     The cache buffer manager
+ * @param usecs   Unused buffers may be released from the cache after this
+ *                time
+ * @param size_factor  Declare buffers that are size_factor times bigger than
+ *                     the requested size as cache hits.
+ * @param bypass_usage  Bitmask. If (requested usage & bypass_usage) != 0,
+ *                      buffer allocation requests are rejected.
+ * @param maximum_cache_size  Maximum size of all unused buffers the cache can
+ *                            hold.
+ * @param destroy_buffer  Function that destroys a buffer for good.
+ * @param can_reclaim     Whether a buffer can be reclaimed (e.g. is not busy)
+ */
+void
+pb_cache_init(struct pb_cache *mgr, uint usecs, float size_factor,
+              unsigned bypass_usage, uint64_t maximum_cache_size,
+              void (*destroy_buffer)(struct pb_buffer *buf),
+              bool (*can_reclaim)(struct pb_buffer *buf))
+{
+   LIST_INITHEAD(&mgr->cache);
+   pipe_mutex_init(mgr->mutex);
+   mgr->cache_size = 0;
+   mgr->max_cache_size = maximum_cache_size;
+   mgr->usecs = usecs;
+   mgr->num_buffers = 0;
+   mgr->bypass_usage = bypass_usage;
+   mgr->size_factor = size_factor;
+   mgr->destroy_buffer = destroy_buffer;
+   mgr->can_reclaim = can_reclaim;
+}
+
+/**
+ * Deinitialize the manager completely.
+ */
+void
+pb_cache_deinit(struct pb_cache *mgr)
+{
+   pb_cache_release_all_buffers(mgr);
+   pipe_mutex_destroy(mgr->mutex);
+}