util: import the slab allocator from gallium

There are also some cosmetic changes.

1 files changed, 62 insertions, 0 deletions

diff --git a/src/util/slab.h b/src/util/slab.h
new file mode 100644
index 0000000..9d13f6a
--- /dev/null
+++ b/src/util/slab.h
@@ -0,0 +1,62 @@
+/*
+ * Copyright 2010 Marek Olšák <maraeo@gmail.com>
+ * Copyright 2016 Advanced Micro Devices, Inc.
+ *
+ * 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
+ * on 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
+ * THE AUTHOR(S) AND/OR THEIR 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. */
+
+/**
+ * Slab allocator for equally sized memory allocations.
+ * The thread-safe path ("*_mt" functions) is usually slower than malloc/free.
+ * The single-threaded path ("*_st" functions) is faster than malloc/free.
+ */
+
+#ifndef SLAB_H
+#define SLAB_H
+
+#include "c11/threads.h"
+
+/* The page is an array of allocations in one block. */
+struct slab_page_header {
+   /* The header (linked-list pointers). */
+   struct slab_page_header *prev, *next;
+
+   /* Memory after the last member is dedicated to the page itself.
+    * The allocated size is always larger than this structure.
+    */
+};
+
+struct slab_mempool {
+   mtx_t mutex;
+   unsigned element_size;
+   unsigned num_elements;
+   struct slab_element_header *first_free;
+   struct slab_page_header list;
+};
+
+void slab_create(struct slab_mempool *pool,
+                 unsigned item_size,
+                 unsigned num_items);
+void slab_destroy(struct slab_mempool *pool);
+void *slab_alloc_st(struct slab_mempool *pool);
+void slab_free_st(struct slab_mempool *pool, void *ptr);
+void *slab_alloc_mt(struct slab_mempool *pool);
+void slab_free_mt(struct slab_mempool *pool, void *ptr);
+
+#endif