Unified double-ended server arena (Phase 1 core). See arena.h for the model. More...

#include "server/mmgr/arena.h"
#include <string.h>

Functions
void	pc_arena_init (pc_arena a, void base, size_t size)
	Initialize `a` over the region `[base, base+size)`.

void *	pc_arena_persist_alloc (pc_arena *a, size_t n)
	Allocate `n` zero-initialized bytes of long-lived storage.

void	pc_arena_persist_free (pc_arena a, void p)
	Free a pointer previously returned by pc_arena_persist_alloc().

void *	pc_arena_scratch_alloc (pc_arena *a, size_t n)
	Bump-allocate `n` transient bytes at the baseline alignment (PC_ARENA_ALIGN).

size_t	pc_arena_free_bytes (const pc_arena *a)
	Free bytes in the middle (max a single new allocation could take, minus a header).

size_t	pc_arena_persist_used (const pc_arena *a)
	Persistent payload bytes currently allocated.

void	pc_arena_set_init (pc_arena_set *s)
	Initialize an empty set (no regions yet).

bool	pc_arena_set_add (pc_arena_set s, void base, size_t size)
	Add a region `[base, base+size)`; regions are searched in the order added.

void *	pc_arena_set_persist_alloc (pc_arena_set *s, size_t n)
	Persistent alloc from the first region that fits (see pc_arena_persist_alloc()).

void	pc_arena_set_persist_free (pc_arena_set s, void p)
	Free a persistent pointer, routed to its owning region by address.

void *	pc_arena_set_scratch_alloc_aligned (pc_arena_set *s, size_t n, size_t align)
	Aligned scratch alloc from the first region that fits (see pc_arena_scratch_alloc_aligned()).

void *	pc_arena_set_scratch_alloc (pc_arena_set *s, size_t n)
	Scratch alloc from the first region that fits (see pc_arena_scratch_alloc()).

pc_arena_mark	pc_arena_set_scratch_mark (const pc_arena_set *s)
	Capture the scratch position of every region.

void	pc_arena_set_scratch_release (pc_arena_set s, const pc_arena_mark m)
	Restore every region's scratch position to `m` (frees scratch made since).

void	pc_arena_set_scratch_reset (pc_arena_set *s)
	Reset scratch in every region.

size_t	pc_arena_set_free_bytes (const pc_arena_set *s)
	Total free middle bytes summed over all regions.

size_t	pc_arena_set_persist_used (const pc_arena_set *s)
	Persistent payload bytes allocated, summed over all regions.

size_t	pc_arena_set_scratch_used (const pc_arena_set *s)
	Scratch bytes allocated, summed over all regions.

Detailed Description

Unified double-ended server arena (Phase 1 core). See arena.h for the model.

Definition in file arena.cpp.

Function Documentation

◆ pc_arena_init()

void pc_arena_init	(	pc_arena *	a,
		void *	base,
		size_t	size
	)

Initialize a over the region [base, base+size).

base should be PC_ARENA_ALIGN-aligned; size must be at least a few blocks.

Definition at line 29 of file arena.cpp.

References pc_arena::base, PC_ARENA_ALIGN, PC_ARENA_MAX_ALIGN, pc_arena::persist_end, pc_arena::persist_hw, pc_arena::persist_used, pc_arena::scratch_hw, pc_arena::scratch_top, and pc_arena::size.

Referenced by pc_arena_set_add().

◆ pc_arena_persist_alloc()

void * pc_arena_persist_alloc	(	pc_arena *	a,
		size_t	n
	)

Allocate n zero-initialized bytes of long-lived storage.

First-fits an existing free block; otherwise carves a new block from the free middle (growing the persistent end up) if it will not cross the scratch end.

Returns: aligned, zeroed pointer, or NULL if the arena cannot satisfy it.

Definition at line 49 of file arena.cpp.

References pc_arena::base, PC_ARENA_ALIGN, pc_arena::persist_end, pc_arena::persist_hw, and pc_arena::persist_used.

Referenced by pc_arena_set_persist_alloc().

◆ pc_arena_persist_free()

void pc_arena_persist_free	(	pc_arena *	a,
		void *	p
	)

Free a pointer previously returned by pc_arena_persist_alloc().

Coalesces with adjacent free blocks; if the freed block sits at the top of the persistent region it returns that space to the free middle (shrinks the boundary). Passing NULL is a no-op.

Definition at line 98 of file arena.cpp.

References pc_arena::base, pc_arena::persist_end, and pc_arena::persist_used.

Referenced by pc_arena_set_persist_free().