zephyr/kernel/mem_slab.c

142 lines
3.3 KiB
C

/*
* Copyright (c) 2016 Wind River Systems, Inc.
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <kernel.h>
#include <kernel_structs.h>
#include <debug/object_tracing_common.h>
#include <toolchain.h>
#include <linker/sections.h>
#include <wait_q.h>
#include <misc/dlist.h>
#include <ksched.h>
#include <init.h>
extern struct k_mem_slab _k_mem_slab_list_start[];
extern struct k_mem_slab _k_mem_slab_list_end[];
static struct k_spinlock lock;
#ifdef CONFIG_OBJECT_TRACING
struct k_mem_slab *_trace_list_k_mem_slab;
#endif /* CONFIG_OBJECT_TRACING */
/**
* @brief Initialize kernel memory slab subsystem.
*
* Perform any initialization of memory slabs that wasn't done at build time.
* Currently this just involves creating the list of free blocks for each slab.
*
* @return N/A
*/
static void create_free_list(struct k_mem_slab *slab)
{
u32_t j;
char *p;
slab->free_list = NULL;
p = slab->buffer;
for (j = 0U; j < slab->num_blocks; j++) {
*(char **)p = slab->free_list;
slab->free_list = p;
p += slab->block_size;
}
}
/**
* @brief Complete initialization of statically defined memory slabs.
*
* Perform any initialization that wasn't done at build time.
*
* @return N/A
*/
static int init_mem_slab_module(struct device *dev)
{
ARG_UNUSED(dev);
struct k_mem_slab *slab;
for (slab = _k_mem_slab_list_start;
slab < _k_mem_slab_list_end;
slab++) {
create_free_list(slab);
SYS_TRACING_OBJ_INIT(k_mem_slab, slab);
z_object_init(slab);
}
return 0;
}
SYS_INIT(init_mem_slab_module, PRE_KERNEL_1,
CONFIG_KERNEL_INIT_PRIORITY_OBJECTS);
void k_mem_slab_init(struct k_mem_slab *slab, void *buffer,
size_t block_size, u32_t num_blocks)
{
/* block size must be word aligned */
__ASSERT((slab->block_size & (sizeof(void *) - 1)) == 0,
"block size not word aligned");
slab->num_blocks = num_blocks;
slab->block_size = block_size;
slab->buffer = buffer;
slab->num_used = 0U;
create_free_list(slab);
z_waitq_init(&slab->wait_q);
SYS_TRACING_OBJ_INIT(k_mem_slab, slab);
z_object_init(slab);
}
int k_mem_slab_alloc(struct k_mem_slab *slab, void **mem, s32_t timeout)
{
k_spinlock_key_t key = k_spin_lock(&lock);
int result;
/* block size must be word aligned */
__ASSERT((slab->block_size & (sizeof(void *) - 1)) == 0,
"block size not word aligned");
if (slab->free_list != NULL) {
/* take a free block */
*mem = slab->free_list;
slab->free_list = *(char **)(slab->free_list);
slab->num_used++;
result = 0;
} else if (timeout == K_NO_WAIT) {
/* don't wait for a free block to become available */
*mem = NULL;
result = -ENOMEM;
} else {
/* wait for a free block or timeout */
result = z_pend_curr(&lock, key, &slab->wait_q, timeout);
if (result == 0) {
*mem = _current->base.swap_data;
}
return result;
}
k_spin_unlock(&lock, key);
return result;
}
void k_mem_slab_free(struct k_mem_slab *slab, void **mem)
{
k_spinlock_key_t key = k_spin_lock(&lock);
struct k_thread *pending_thread = z_unpend_first_thread(&slab->wait_q);
if (pending_thread != NULL) {
z_set_thread_return_value_with_data(pending_thread, 0, *mem);
z_ready_thread(pending_thread);
z_reschedule(&lock, key);
} else {
**(char ***)mem = slab->free_list;
slab->free_list = *(char **)mem;
slab->num_used--;
k_spin_unlock(&lock, key);
}
}