[Mesa-dev] [PATCH 1/2] util: import the slab allocator from gallium
Marek Olšák
maraeo at gmail.com
Mon Aug 29 15:29:36 UTC 2016
From: Marek Olšák <marek.olsak at amd.com>
There are also some cosmetic changes.
---
src/util/Makefile.sources | 2 +
src/util/slab.c | 180 ++++++++++++++++++++++++++++++++++++++++++++++
src/util/slab.h | 62 ++++++++++++++++
3 files changed, 244 insertions(+)
create mode 100644 src/util/slab.c
create mode 100644 src/util/slab.h
diff --git a/src/util/Makefile.sources b/src/util/Makefile.sources
index 6def4f7..d72107a 100644
--- a/src/util/Makefile.sources
+++ b/src/util/Makefile.sources
@@ -18,19 +18,21 @@ MESA_UTIL_FILES := \
ralloc.c \
ralloc.h \
register_allocate.c \
register_allocate.h \
rgtc.c \
rgtc.h \
rounding.h \
set.c \
set.h \
simple_list.h \
+ slab.c \
+ slab.h \
strndup.c \
strndup.h \
strtod.c \
strtod.h \
texcompress_rgtc_tmp.h \
u_atomic.h
MESA_UTIL_GENERATED_FILES = \
format_srgb.c
diff --git a/src/util/slab.c b/src/util/slab.c
new file mode 100644
index 0000000..acf818b
--- /dev/null
+++ b/src/util/slab.c
@@ -0,0 +1,180 @@
+/*
+ * Copyright 2010 Marek Olšák <maraeo at 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. */
+
+#include "slab.h"
+#include "macros.h"
+#include "simple_list.h"
+#include <stdbool.h>
+#include <string.h>
+
+#define ALIGN(value, align) (((value) + (align) - 1) & ~((align) - 1))
+
+#ifdef DEBUG
+#define SLAB_MAGIC 0xcafe4321
+#define SET_MAGIC(element) (element)->magic = SLAB_MAGIC
+#define CHECK_MAGIC(element) assert((element)->magic == SLAB_MAGIC)
+#else
+#define SET_MAGIC(element)
+#define CHECK_MAGIC(element)
+#endif
+
+/* One array element within a big buffer. */
+struct slab_element_header {
+ /* The next free element. */
+ struct slab_element_header *next_free;
+
+#ifdef DEBUG
+ /* Use intptr_t to keep the header aligned to a pointer size. */
+ intptr_t magic;
+#endif
+};
+
+static struct slab_element_header *
+slab_get_element(struct slab_mempool *pool,
+ struct slab_page_header *page, unsigned index)
+{
+ return (struct slab_element_header*)
+ ((uint8_t*)&page[1] + (pool->element_size * index));
+}
+
+static bool
+slab_add_new_page(struct slab_mempool *pool)
+{
+ struct slab_page_header *page;
+ struct slab_element_header *element;
+ unsigned i;
+
+ page = malloc(sizeof(struct slab_page_header) +
+ pool->num_elements * pool->element_size);
+ if (!page)
+ return false;
+
+ if (!pool->list.prev)
+ make_empty_list(&pool->list);
+
+ insert_at_tail(&pool->list, page);
+
+ /* Mark all elements as free. */
+ for (i = 0; i < pool->num_elements-1; i++) {
+ element = slab_get_element(pool, page, i);
+ element->next_free = slab_get_element(pool, page, i + 1);
+ SET_MAGIC(element);
+ }
+
+ element = slab_get_element(pool, page, pool->num_elements - 1);
+ element->next_free = pool->first_free;
+ SET_MAGIC(element);
+ pool->first_free = slab_get_element(pool, page, 0);
+ return true;
+}
+
+/**
+ * Allocate an object from the slab. Single-threaded (no mutex).
+ */
+void *
+slab_alloc_st(struct slab_mempool *pool)
+{
+ struct slab_element_header *element;
+
+ /* Allocate a new page. */
+ if (!pool->first_free &&
+ !slab_add_new_page(pool))
+ return NULL;
+
+ element = pool->first_free;
+ CHECK_MAGIC(element);
+ pool->first_free = element->next_free;
+ return &element[1];
+}
+
+/**
+ * Free an object allocated from the slab. Single-threaded (no mutex).
+ */
+void
+slab_free_st(struct slab_mempool *pool, void *ptr)
+{
+ struct slab_element_header *element =
+ ((struct slab_element_header*)ptr - 1);
+
+ CHECK_MAGIC(element);
+ element->next_free = pool->first_free;
+ pool->first_free = element;
+}
+
+/**
+ * Allocate an object from the slab. Thread-safe.
+ */
+void *
+slab_alloc_mt(struct slab_mempool *pool)
+{
+ void *mem;
+
+ mtx_lock(&pool->mutex);
+ mem = slab_alloc_st(pool);
+ mtx_unlock(&pool->mutex);
+ return mem;
+}
+
+/**
+ * Free an object allocated from the slab. Thread-safe.
+ */
+void
+slab_free_mt(struct slab_mempool *pool, void *ptr)
+{
+ mtx_lock(&pool->mutex);
+ slab_free_st(pool, ptr);
+ mtx_unlock(&pool->mutex);
+}
+
+void
+slab_destroy(struct slab_mempool *pool)
+{
+ struct slab_page_header *page, *temp;
+
+ if (pool->list.next) {
+ foreach_s(page, temp, &pool->list) {
+ remove_from_list(page);
+ free(page);
+ }
+ }
+
+ mtx_destroy(&pool->mutex);
+}
+
+/**
+ * Create an allocator for same-sized objects.
+ *
+ * \param item_size Size of one object.
+ * \param num_items Number of objects to allocate at once.
+ */
+void
+slab_create(struct slab_mempool *pool,
+ unsigned item_size,
+ unsigned num_items)
+{
+ mtx_init(&pool->mutex, mtx_plain);
+ pool->element_size = ALIGN(sizeof(struct slab_element_header) + item_size,
+ sizeof(intptr_t));
+ pool->num_elements = num_items;
+ pool->first_free = NULL;
+}
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 at 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
--
2.7.4
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