arena.c File Reference

Request-scoped arena allocator built on libttak arena generations. More...

#include <cwist/core/mem/arena.h>
#include <cwist/sys/platform.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdlib.h>

Include dependency graph for arena.c:

Go to the source code of this file.

Functions
cwist_arena_t *	cwist_arena_create (size_t generation_bytes)
	Create an arena backed by a recycled thread-local generation buffer.
void *	cwist_arena_alloc (cwist_arena_t *arena, size_t size)
	Bump-allocate size bytes from the active generation.
bool	cwist_arena_owns (const cwist_arena_t *arena, const void *ptr)
	Check whether ptr lies inside the active generation buffer.
void	cwist_arena_destroy (cwist_arena_t *arena)
	Retire the generation and destroy the arena, releasing every allocation made from it at once.

Detailed Description

Request-scoped arena allocator built on libttak arena generations.

Performance notes:

• Generation buffers are recycled through a per-thread free list, so the steady-state request cycle performs no libttak mem-tree registration or epoch-GC work at all; ttak_mem_alloc/free is only touched when the cache underflows/overflows (thread start or concurrency watermark changes).
• The ttak_arena_env_t (epoch/GC coordinator) lives in thread-local storage and is initialized once per thread, never per request.
• Cleanup on thread exit is handled through a pthread key destructor, which keeps this file portable C11/POSIX with no architecture-specific code.

Definition in file arena.c.

Function Documentation

cwist_arena_alloc()

void * cwist_arena_alloc	(	cwist_arena_t *	arena,
		size_t	size
	)

Bump-allocate size bytes from the active generation.

Returns

Aligned chunk, or NULL when the generation is exhausted (callers should fall back to cwist_alloc).

Note

The returned memory is NOT zeroed.

Definition at line 44 of file arena.c.

cwist_arena_create()

cwist_arena_t * cwist_arena_create

(

size_t

generation_bytes

)

Create an arena backed by a recycled thread-local generation buffer.

Parameters

generation_bytes

Capacity of the generation buffer (0 = default).

Returns

New arena, or NULL on failure (callers should fall back to heap).

Note

Default-sized buffers come from a per-thread recycle cache, so steady-state creation triggers no libttak GC/mem-tree activity.

Definition at line 32 of file arena.c.

References CWIST_ARENA_DEFAULT_GENERATION_BYTES.

Referenced by cwist_http_request_create(), and cwist_http_response_create().

cwist_arena_destroy()

void cwist_arena_destroy

(

cwist_arena_t *

arena

)

Retire the generation and destroy the arena, releasing every allocation made from it at once.

Definition at line 60 of file arena.c.

Referenced by cwist_http_request_create(), cwist_http_request_destroy(), cwist_http_response_create(), and cwist_http_response_destroy().

cwist_arena_owns()

bool cwist_arena_owns	(	const cwist_arena_t *	arena,
		const void *	ptr
	)

Check whether ptr lies inside the active generation buffer.

Definition at line 54 of file arena.c.

Referenced by cwist_http_request_destroy(), and cwist_http_response_destroy().