michaelh/zephyr
1
0
Fork 0
Code Releases Activity

lib: user mode compatible mempools

Browse source 
We would like to offer the capability to have memory pool heap data
structures that are usable from user mode threads. The current
k_mem_pool implementation uses IRQ locking and system-wide membership
lists that make it incompatible with user mode constraints.

However, much of the existing memory pool code can be abstracted to some
common functions that are used by both k_mem_pool and the new
sys_mem_pool implementations.

The sys_mem_pool implementation has the following differences:

* The alloc/free APIs work directly with pointers, no internal memory
block structures are exposed to the end user. A pointer to the source
pool is provided for allocation, but freeing memory just requires the
pointer and nothing else.

* k_mem_pool uses IRQ locks and required very fine-grained locking in
order to not affect system latency. sys_mem_pools just use a semaphore
to protect the pool data structures at the API level, since there aren't
implications for system responsiveness with this kind of concurrency
control.

* sys_mem_pools do not support the notion of timeouts for requesting
memory.

* sys_mem_pools are specified at compile time with macros, just like
kernel memory pools. Alternative forms of specification at runtime
will be a later enhancement.

Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
This commit is contained in:
Andrew Boie 2018-03-06 17:12:37 -08:00 • committed by Andrew Boie
commit aa6de29c4b
7 changed files with 586 additions and 339 deletions
Download patch file Download diff file Expand all files Collapse all files

93
include/kernel.h
View file

@ -25,6 +25,7 @@
#include <misc/dlist.h>
#include <misc/slist.h>
#include <misc/util.h>
#include <misc/mempool_base.h>
#include <kernel_version.h>
#include <random/rand32.h>
#include <kernel_arch_thread.h>
@ -3544,86 +3545,11 @@ static inline u32_t k_mem_slab_num_free_get(struct k_mem_slab *slab)
* @cond INTERNAL_HIDDEN
*/
struct k_mem_pool_lvl {
union {
u32_t *bits_p;
u32_t bits;
};
sys_dlist_t free_list;
};
struct k_mem_pool {
void *buf;
size_t max_sz;
u16_t n_max;
u8_t n_levels;
u8_t max_inline_level;
struct k_mem_pool_lvl *levels;
struct sys_mem_pool_base base;
_wait_q_t wait_q;
};
#define _ALIGN4(n) ((((n)+3)/4)*4)
#define _MPOOL_HAVE_LVL(max, min, l) (((max) >> (2*(l))) >= (min) ? 1 : 0)
#define __MPOOL_LVLS(maxsz, minsz) \
(_MPOOL_HAVE_LVL((maxsz), (minsz), 0) + \
_MPOOL_HAVE_LVL((maxsz), (minsz), 1) + \
_MPOOL_HAVE_LVL((maxsz), (minsz), 2) + \
_MPOOL_HAVE_LVL((maxsz), (minsz), 3) + \
_MPOOL_HAVE_LVL((maxsz), (minsz), 4) + \
_MPOOL_HAVE_LVL((maxsz), (minsz), 5) + \
_MPOOL_HAVE_LVL((maxsz), (minsz), 6) + \
_MPOOL_HAVE_LVL((maxsz), (minsz), 7) + \
_MPOOL_HAVE_LVL((maxsz), (minsz), 8) + \
_MPOOL_HAVE_LVL((maxsz), (minsz), 9) + \
_MPOOL_HAVE_LVL((maxsz), (minsz), 10) + \
_MPOOL_HAVE_LVL((maxsz), (minsz), 11) + \
_MPOOL_HAVE_LVL((maxsz), (minsz), 12) + \
_MPOOL_HAVE_LVL((maxsz), (minsz), 13) + \
_MPOOL_HAVE_LVL((maxsz), (minsz), 14) + \
_MPOOL_HAVE_LVL((maxsz), (minsz), 15))
#define _MPOOL_MINBLK sizeof(sys_dnode_t)
#define _MPOOL_LVLS(max, min) \
__MPOOL_LVLS((max), (min) >= _MPOOL_MINBLK ? (min) : _MPOOL_MINBLK)
/* Rounds the needed bits up to integer multiples of u32_t */
#define _MPOOL_LBIT_WORDS_UNCLAMPED(n_max, l) \
((((n_max) << (2*(l))) + 31) / 32)
/* One word gets stored free unioned with the pointer, otherwise the
* calculated unclamped value
*/
#define _MPOOL_LBIT_WORDS(n_max, l) \
(_MPOOL_LBIT_WORDS_UNCLAMPED(n_max, l) < 2 ? 0 \
: _MPOOL_LBIT_WORDS_UNCLAMPED(n_max, l))
/* How many bytes for the bitfields of a single level? */
#define _MPOOL_LBIT_BYTES(maxsz, minsz, l, n_max) \
(_MPOOL_LVLS((maxsz), (minsz)) >= (l) ? \
4 * _MPOOL_LBIT_WORDS((n_max), l) : 0)
/* Size of the bitmap array that follows the buffer in allocated memory */
#define _MPOOL_BITS_SIZE(maxsz, minsz, n_max) \
(_MPOOL_LBIT_BYTES(maxsz, minsz, 0, n_max) + \
_MPOOL_LBIT_BYTES(maxsz, minsz, 1, n_max) + \
_MPOOL_LBIT_BYTES(maxsz, minsz, 2, n_max) + \
_MPOOL_LBIT_BYTES(maxsz, minsz, 3, n_max) + \
_MPOOL_LBIT_BYTES(maxsz, minsz, 4, n_max) + \
_MPOOL_LBIT_BYTES(maxsz, minsz, 5, n_max) + \
_MPOOL_LBIT_BYTES(maxsz, minsz, 6, n_max) + \
_MPOOL_LBIT_BYTES(maxsz, minsz, 7, n_max) + \
_MPOOL_LBIT_BYTES(maxsz, minsz, 8, n_max) + \
_MPOOL_LBIT_BYTES(maxsz, minsz, 9, n_max) + \
_MPOOL_LBIT_BYTES(maxsz, minsz, 10, n_max) + \
_MPOOL_LBIT_BYTES(maxsz, minsz, 11, n_max) + \
_MPOOL_LBIT_BYTES(maxsz, minsz, 12, n_max) + \
_MPOOL_LBIT_BYTES(maxsz, minsz, 13, n_max) + \
_MPOOL_LBIT_BYTES(maxsz, minsz, 14, n_max) + \
_MPOOL_LBIT_BYTES(maxsz, minsz, 15, n_max))
/**
* INTERNAL_HIDDEN @endcond
*/
@ -3655,13 +3581,16 @@ struct k_mem_pool {
#define K_MEM_POOL_DEFINE(name, minsz, maxsz, nmax, align) \
char __aligned(align) _mpool_buf_##name[_ALIGN4(maxsz * nmax) \
+ _MPOOL_BITS_SIZE(maxsz, minsz, nmax)]; \
struct k_mem_pool_lvl _mpool_lvls_##name[_MPOOL_LVLS(maxsz, minsz)]; \
struct sys_mem_pool_lvl _mpool_lvls_##name[_MPOOL_LVLS(maxsz, minsz)]; \
struct k_mem_pool name __in_section(_k_mem_pool, static, name) = { \
.buf = _mpool_buf_##name, \
.max_sz = maxsz, \
.n_max = nmax, \
.n_levels = _MPOOL_LVLS(maxsz, minsz), \
.levels = _mpool_lvls_##name, \
.base = { \
.buf = _mpool_buf_##name, \
.max_sz = maxsz, \
.n_max = nmax, \
.n_levels = _MPOOL_LVLS(maxsz, minsz), \
.levels = _mpool_lvls_##name, \
.flags = SYS_MEM_POOL_KERNEL \
} \
}
/**