[Mesa-dev] [PATCH 06/15] ralloc: add a linear allocator as a child node of ralloc
Marek Olšák
maraeo at gmail.com
Sat Oct 8 10:58:30 UTC 2016
From: Marek Olšák <marek.olsak at amd.com>
---
src/util/ralloc.c | 355 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
src/util/ralloc.h | 84 ++++++++++++-
2 files changed, 435 insertions(+), 4 deletions(-)
diff --git a/src/util/ralloc.c b/src/util/ralloc.c
index bf21ac3..a8e660f 100644
--- a/src/util/ralloc.c
+++ b/src/util/ralloc.c
@@ -522,10 +522,365 @@ ralloc_vasprintf_rewrite_tail(char **str, size_t *start, const char *fmt,
ptr = resize(*str, *start + new_length + 1);
if (unlikely(ptr == NULL))
return false;
vsnprintf(ptr + *start, new_length + 1, fmt, args);
*str = ptr;
*start += new_length;
return true;
}
+
+/***************************************************************************
+ * Linear allocator for short-lived allocations.
+ ***************************************************************************
+ *
+ * The allocator consists of a parent node (2K buffer), which requires
+ * a ralloc parent, and child nodes (allocations). Child nodes can't be freed
+ * directly, because the parent doesn't track them. You have to release
+ * the parent node in order to release all its children.
+ *
+ * The allocator uses a fixed-sized buffer with a monotonically increasing
+ * offset after each allocation. If the buffer is all used, another buffer
+ * is allocated, sharing the same ralloc parent, so all buffers are at
+ * the same level in the ralloc hierarchy.
+ *
+ * The linear parent node is always the first buffer and keeps track of all
+ * other buffers.
+ */
+
+#define ALIGN(x, y) (((x) + (y) - 1) & ~((y) - 1))
+
+#define MIN_LINEAR_BUFSIZE 2048
+#define LMAGIC 0x87b9c7d3
+
+struct linear_header {
+#ifdef DEBUG
+ unsigned magic; /* for debugging */
+#endif
+ unsigned offset; /* points to the first unused byte in the buffer */
+ unsigned size; /* size of the buffer */
+ void *ralloc_parent; /* new buffers will use this */
+ struct linear_header *next; /* next buffer if we have more */
+ struct linear_header *latest; /* the only buffer that has free space */
+
+ /* After this structure, the buffer begins.
+ * Each suballocation consists of linear_size_chunk as its header followed
+ * by the suballocation, so it goes:
+ *
+ * - linear_size_chunk
+ * - allocated space
+ * - linear_size_chunk
+ * - allocated space
+ * etc.
+ *
+ * linear_size_chunk is only needed by linear_realloc.
+ */
+};
+
+struct linear_size_chunk {
+ unsigned size; /* for realloc */
+ unsigned _padding;
+};
+
+typedef struct linear_header linear_header;
+typedef struct linear_size_chunk linear_size_chunk;
+
+#define LINEAR_PARENT_TO_HEADER(parent) \
+ (linear_header*) \
+ ((char*)(parent) - sizeof(linear_size_chunk) - sizeof(linear_header))
+
+/* Allocate the linear buffer with its header. */
+static linear_header *
+create_linear_node(void *ralloc_ctx, unsigned min_size)
+{
+ linear_header *node;
+
+ min_size += sizeof(linear_size_chunk);
+
+ if (likely(min_size < MIN_LINEAR_BUFSIZE))
+ min_size = MIN_LINEAR_BUFSIZE;
+
+ node = ralloc_size(ralloc_ctx, sizeof(linear_header) + min_size);
+ if (unlikely(!node))
+ return NULL;
+
+#ifdef DEBUG
+ node->magic = LMAGIC;
+#endif
+ node->offset = 0;
+ node->size = min_size;
+ node->ralloc_parent = ralloc_ctx;
+ node->next = NULL;
+ node->latest = node;
+ return node;
+}
+
+void *
+linear_alloc_child(void *parent, unsigned size)
+{
+ linear_header *first = LINEAR_PARENT_TO_HEADER(parent);
+ linear_header *latest = first->latest;
+ linear_header *new_node;
+ linear_size_chunk *ptr;
+ unsigned full_size;
+
+ assert(first->magic == LMAGIC);
+ assert(!latest->next);
+
+ size = ALIGN(size, 8);
+ full_size = sizeof(linear_size_chunk) + size;
+
+ if (likely(latest->offset + full_size <= latest->size)) {
+alloc:
+ ptr = (linear_size_chunk *)((char*)&latest[1] + latest->offset);
+ ptr->size = size;
+ latest->offset += full_size;
+ return &ptr[1];
+ }
+
+ /* allocate a new node */
+ new_node = create_linear_node(latest->ralloc_parent, size);
+ if (unlikely(!new_node))
+ return NULL;
+
+ first->latest = new_node;
+ latest->latest = new_node;
+ latest->next = new_node;
+ latest = new_node;
+
+ goto alloc;
+}
+
+void *
+linear_alloc_parent(void *ralloc_ctx, unsigned size)
+{
+ linear_header *node;
+
+ if (unlikely(!ralloc_ctx))
+ return NULL;
+
+ size = ALIGN(size, 8);
+
+ node = create_linear_node(ralloc_ctx, size);
+ if (unlikely(!node))
+ return NULL;
+
+ return linear_alloc_child((char*)node +
+ sizeof(linear_header) +
+ sizeof(linear_size_chunk), size);
+}
+
+void *
+linear_zalloc_child(void *parent, unsigned size)
+{
+ void *ptr = linear_alloc_child(parent, size);
+
+ if (likely(ptr))
+ memset(ptr, 0, size);
+ return ptr;
+}
+
+void *
+linear_zalloc_parent(void *parent, unsigned size)
+{
+ void *ptr = linear_alloc_parent(parent, size);
+
+ if (likely(ptr))
+ memset(ptr, 0, size);
+ return ptr;
+}
+
+void
+linear_free_parent(void *ptr)
+{
+ linear_header *node;
+
+ if (unlikely(!ptr))
+ return;
+
+ node = LINEAR_PARENT_TO_HEADER(ptr);
+ assert(node->magic == LMAGIC);
+
+ while (node) {
+ void *ptr = node;
+
+ node = node->next;
+ ralloc_free(ptr);
+ }
+}
+
+void
+ralloc_steal_linear_parent(void *new_ralloc_ctx, void *ptr)
+{
+ linear_header *node;
+
+ if (unlikely(!ptr))
+ return;
+
+ node = LINEAR_PARENT_TO_HEADER(ptr);
+ assert(node->magic == LMAGIC);
+
+ while (node) {
+ ralloc_steal(new_ralloc_ctx, node);
+ node->ralloc_parent = new_ralloc_ctx;
+ node = node->next;
+ }
+}
+
+void *
+ralloc_parent_of_linear_parent(void *ptr)
+{
+ linear_header *node = LINEAR_PARENT_TO_HEADER(ptr);
+ assert(node->magic == LMAGIC);
+ return node->ralloc_parent;
+}
+
+void *
+linear_realloc(void *parent, void *old, unsigned new_size)
+{
+ size_t old_size = 0;
+ ralloc_header *new_ptr;
+
+ new_ptr = linear_alloc_child(parent, new_size);
+
+ if (unlikely(!old))
+ return new_ptr;
+
+ old_size = ((linear_size_chunk*)old)[-1].size;
+
+ if (likely(new_ptr && old_size))
+ memcpy(new_ptr, old, old_size > new_size ? new_size : old_size);
+
+ return new_ptr;
+}
+
+/* All code below is pretty much copied from ralloc and only the alloc
+ * calls are different.
+ */
+
+char *
+linear_strdup(void *parent, const char *str)
+{
+ size_t n;
+ char *ptr;
+
+ if (unlikely(!str))
+ return NULL;
+
+ n = strlen(str);
+ ptr = linear_alloc_child(parent, n + 1);
+ if (unlikely(!ptr))
+ return NULL;
+
+ memcpy(ptr, str, n);
+ ptr[n] = '\0';
+ return ptr;
+}
+
+char *
+linear_asprintf(void *parent, const char *fmt, ...)
+{
+ char *ptr;
+ va_list args;
+ va_start(args, fmt);
+ ptr = linear_vasprintf(parent, fmt, args);
+ va_end(args);
+ return ptr;
+}
+
+char *
+linear_vasprintf(void *parent, const char *fmt, va_list args)
+{
+ size_t size = printf_length(fmt, args) + 1;
+
+ char *ptr = linear_alloc_child(parent, size);
+ if (ptr != NULL)
+ vsnprintf(ptr, size, fmt, args);
+
+ return ptr;
+}
+
+bool
+linear_asprintf_append(void *parent, char **str, const char *fmt, ...)
+{
+ bool success;
+ va_list args;
+ va_start(args, fmt);
+ success = linear_vasprintf_append(parent, str, fmt, args);
+ va_end(args);
+ return success;
+}
+
+bool
+linear_vasprintf_append(void *parent, char **str, const char *fmt, va_list args)
+{
+ size_t existing_length;
+ assert(str != NULL);
+ existing_length = *str ? strlen(*str) : 0;
+ return linear_vasprintf_rewrite_tail(parent, str, &existing_length, fmt, args);
+}
+
+bool
+linear_asprintf_rewrite_tail(void *parent, char **str, size_t *start,
+ const char *fmt, ...)
+{
+ bool success;
+ va_list args;
+ va_start(args, fmt);
+ success = linear_vasprintf_rewrite_tail(parent, str, start, fmt, args);
+ va_end(args);
+ return success;
+}
+
+bool
+linear_vasprintf_rewrite_tail(void *parent, char **str, size_t *start,
+ const char *fmt, va_list args)
+{
+ size_t new_length;
+ char *ptr;
+
+ assert(str != NULL);
+
+ if (unlikely(*str == NULL)) {
+ *str = linear_vasprintf(parent, fmt, args);
+ *start = strlen(*str);
+ return true;
+ }
+
+ new_length = printf_length(fmt, args);
+
+ ptr = linear_realloc(parent, *str, *start + new_length + 1);
+ if (unlikely(ptr == NULL))
+ return false;
+
+ vsnprintf(ptr + *start, new_length + 1, fmt, args);
+ *str = ptr;
+ *start += new_length;
+ return true;
+}
+
+/* helper routine for strcat/strncat - n is the exact amount to copy */
+static bool
+linear_cat(void *parent, char **dest, const char *str, size_t n)
+{
+ char *both;
+ size_t existing_length;
+ assert(dest != NULL && *dest != NULL);
+
+ existing_length = strlen(*dest);
+ both = linear_realloc(parent, *dest, existing_length + n + 1);
+ if (unlikely(both == NULL))
+ return false;
+
+ memcpy(both + existing_length, str, n);
+ both[existing_length + n] = '\0';
+
+ *dest = both;
+ return true;
+}
+
+bool
+linear_strcat(void *parent, char **dest, const char *str)
+{
+ return linear_cat(parent, dest, str, strlen(str));
+}
diff --git a/src/util/ralloc.h b/src/util/ralloc.h
index d74a398..3e2d342 100644
--- a/src/util/ralloc.h
+++ b/src/util/ralloc.h
@@ -400,24 +400,20 @@ bool ralloc_asprintf_append (char **str, const char *fmt, ...)
* \sa ralloc_vasprintf_rewrite_tail
* \sa ralloc_strcat
*
* \p str will be updated to the new pointer unless allocation fails.
*
* \return True unless allocation failed.
*/
bool ralloc_vasprintf_append(char **str, const char *fmt, va_list args);
/// @}
-#ifdef __cplusplus
-} /* end of extern "C" */
-#endif
-
/**
* Declare C++ new and delete operators which use ralloc.
*
* Placing this macro in the body of a class makes it possible to do:
*
* TYPE *var = new(mem_ctx) TYPE(...);
* delete var;
*
* which is more idiomatic in C++ than calling ralloc.
*/
@@ -447,11 +443,91 @@ public: \
ralloc_set_destructor(p, NULL); \
ralloc_free(p); \
}
#define DECLARE_RALLOC_CXX_OPERATORS(type) \
DECLARE_ALLOC_CXX_OPERATORS_TEMPLATE(type, ralloc_size)
#define DECLARE_RZALLOC_CXX_OPERATORS(type) \
DECLARE_ALLOC_CXX_OPERATORS_TEMPLATE(type, rzalloc_size)
+#define DECLARE_LINEAR_ALLOC_CXX_OPERATORS(type) \
+ DECLARE_ALLOC_CXX_OPERATORS_TEMPLATE(type, linear_alloc_child)
+
+#define DECLARE_LINEAR_ZALLOC_CXX_OPERATORS(type) \
+ DECLARE_ALLOC_CXX_OPERATORS_TEMPLATE(type, linear_zalloc_child)
+
+
+/**
+ * Do a fast allocation from the linear buffer, also known as the child node
+ * from the allocator's point of view. It can't be freed directly. You have
+ * to free the parent or the ralloc parent.
+ *
+ * \param parent parent node of the linear allocator
+ * \param size size to allocate (max 32 bits)
+ */
+void *linear_alloc_child(void *parent, unsigned size);
+
+/**
+ * Allocate a parent node that will hold linear buffers. The returned
+ * allocation is actually the first child node, but it's also the handle
+ * of the parent node. Use it for all child node allocations.
+ *
+ * \param ralloc_ctx ralloc context, must not be NULL
+ * \param size size to allocate (max 32 bits)
+ */
+void *linear_alloc_parent(void *ralloc_ctx, unsigned size);
+
+/**
+ * Same as linear_alloc_child, but also clears memory.
+ */
+void *linear_zalloc_child(void *parent, unsigned size);
+
+/**
+ * Same as linear_alloc_parent, but also clears memory.
+ */
+void *linear_zalloc_parent(void *ralloc_ctx, unsigned size);
+
+/**
+ * Free the linear parent node. This will free all child nodes too.
+ * Freeing the ralloc parent will also free this.
+ */
+void linear_free_parent(void *ptr);
+
+/**
+ * Same as ralloc_steal, but steals the linear parent node.
+ */
+void ralloc_steal_linear_parent(void *new_ralloc_ctx, void *ptr);
+
+/**
+ * Return the ralloc parent of the linear parent node.
+ */
+void *ralloc_parent_of_linear_parent(void *ptr);
+
+/**
+ * Same as realloc except that the linear allocator doesn't free child nodes,
+ * so it's reduced to memory duplication. It's used in places where
+ * reallocation is required. Don't use it often. It's much slower than
+ * realloc.
+ */
+void *linear_realloc(void *parent, void *old, unsigned new_size);
+
+/* The functions below have the same semantics as their ralloc counterparts,
+ * except that they always allocate a linear child node.
+ */
+char *linear_strdup(void *parent, const char *str);
+char *linear_asprintf(void *parent, const char *fmt, ...);
+char *linear_vasprintf(void *parent, const char *fmt, va_list args);
+bool linear_asprintf_append(void *parent, char **str, const char *fmt, ...);
+bool linear_vasprintf_append(void *parent, char **str, const char *fmt,
+ va_list args);
+bool linear_asprintf_rewrite_tail(void *parent, char **str, size_t *start,
+ const char *fmt, ...);
+bool linear_vasprintf_rewrite_tail(void *parent, char **str, size_t *start,
+ const char *fmt, va_list args);
+bool linear_strcat(void *parent, char **dest, const char *str);
+
+#ifdef __cplusplus
+} /* end of extern "C" */
+#endif
+
#endif
--
2.7.4
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