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rt-thread/src/slab.c

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/*
* Copyright (c) 2006-2018, RT-Thread Development Team
*
* SPDX-License-Identifier: Apache-2.0
*/
/*
* File : slab.c
*
* Change Logs:
* Date Author Notes
* 2008-07-12 Bernard the first version
* 2010-07-13 Bernard fix RT_ALIGN issue found by kuronca
* 2010-10-23 yi.qiu add module memory allocator
* 2010-12-18 yi.qiu fix zone release bug
*/
/*
* KERN_SLABALLOC.C - Kernel SLAB memory allocator
*
* Copyright (c) 2003,2004 The DragonFly Project. All rights reserved.
*
* This code is derived from software contributed to The DragonFly Project
* by Matthew Dillon <dillon@backplane.com>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name of The DragonFly Project nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific, prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
*/
#include <rthw.h>
#include <rtthread.h>
#define RT_MEM_STATS
#if defined (RT_USING_HEAP) && defined (RT_USING_SLAB)
/* some statistical variable */
#ifdef RT_MEM_STATS
static rt_size_t used_mem, max_mem;
#endif
#ifdef RT_USING_HOOK
static void (*rt_malloc_hook)(void *ptr, rt_size_t size);
static void (*rt_free_hook)(void *ptr);
/**
* @addtogroup Hook
*/
/**@{*/
/**
* This function will set a hook function, which will be invoked when a memory
* block is allocated from heap memory.
*
* @param hook the hook function
*/
void rt_malloc_sethook(void (*hook)(void *ptr, rt_size_t size))
{
rt_malloc_hook = hook;
}
RTM_EXPORT(rt_malloc_sethook);
/**
* This function will set a hook function, which will be invoked when a memory
* block is released to heap memory.
*
* @param hook the hook function
*/
void rt_free_sethook(void (*hook)(void *ptr))
{
rt_free_hook = hook;
}
RTM_EXPORT(rt_free_sethook);
/**@}*/
#endif
/*
* slab allocator implementation
*
* A slab allocator reserves a ZONE for each chunk size, then lays the
* chunks out in an array within the zone. Allocation and deallocation
* is nearly instantanious, and fragmentation/overhead losses are limited
* to a fixed worst-case amount.
*
* The downside of this slab implementation is in the chunk size
* multiplied by the number of zones. ~80 zones * 128K = 10MB of VM per cpu.
* In a kernel implementation all this memory will be physical so
* the zone size is adjusted downward on machines with less physical
* memory. The upside is that overhead is bounded... this is the *worst*
* case overhead.
*
* Slab management is done on a per-cpu basis and no locking or mutexes
* are required, only a critical section. When one cpu frees memory
* belonging to another cpu's slab manager an asynchronous IPI message
* will be queued to execute the operation. In addition, both the
* high level slab allocator and the low level zone allocator optimize
* M_ZERO requests, and the slab allocator does not have to pre initialize
* the linked list of chunks.
*
* XXX Balancing is needed between cpus. Balance will be handled through
* asynchronous IPIs primarily by reassigning the z_Cpu ownership of chunks.
*
* XXX If we have to allocate a new zone and M_USE_RESERVE is set, use of
* the new zone should be restricted to M_USE_RESERVE requests only.
*
* Alloc Size Chunking Number of zones
* 0-127 8 16
* 128-255 16 8
* 256-511 32 8
* 512-1023 64 8
* 1024-2047 128 8
* 2048-4095 256 8
* 4096-8191 512 8
* 8192-16383 1024 8
* 16384-32767 2048 8
* (if RT_MM_PAGE_SIZE is 4K the maximum zone allocation is 16383)
*
* Allocations >= zone_limit go directly to kmem.
*
* API REQUIREMENTS AND SIDE EFFECTS
*
* To operate as a drop-in replacement to the FreeBSD-4.x malloc() we
* have remained compatible with the following API requirements:
*
* + small power-of-2 sized allocations are power-of-2 aligned (kern_tty)
* + all power-of-2 sized allocations are power-of-2 aligned (twe)
* + malloc(0) is allowed and returns non-RT_NULL (ahc driver)
* + ability to allocate arbitrarily large chunks of memory
*/
/*
* Chunk structure for free elements
*/
typedef struct slab_chunk
{
struct slab_chunk *c_next;
} slab_chunk;
/*
* The IN-BAND zone header is placed at the beginning of each zone.
*/
typedef struct slab_zone
{
rt_int32_t z_magic; /* magic number for sanity check */
rt_int32_t z_nfree; /* total free chunks / ualloc space in zone */
rt_int32_t z_nmax; /* maximum free chunks */
struct slab_zone *z_next; /* zoneary[] link if z_nfree non-zero */
rt_uint8_t *z_baseptr; /* pointer to start of chunk array */
rt_int32_t z_uindex; /* current initial allocation index */
rt_int32_t z_chunksize; /* chunk size for validation */
rt_int32_t z_zoneindex; /* zone index */
slab_chunk *z_freechunk; /* free chunk list */
} slab_zone;
#define ZALLOC_SLAB_MAGIC 0x51ab51ab
#define ZALLOC_ZONE_LIMIT (16 * 1024) /* max slab-managed alloc */
#define ZALLOC_MIN_ZONE_SIZE (32 * 1024) /* minimum zone size */
#define ZALLOC_MAX_ZONE_SIZE (128 * 1024) /* maximum zone size */
#define NZONES 72 /* number of zones */
#define ZONE_RELEASE_THRESH 2 /* threshold number of zones */
static slab_zone *zone_array[NZONES]; /* linked list of zones NFree > 0 */
static slab_zone *zone_free; /* whole zones that have become free */
static int zone_free_cnt;
static int zone_size;
static int zone_limit;
static int zone_page_cnt;
/*
* Misc constants. Note that allocations that are exact multiples of
* RT_MM_PAGE_SIZE, or exceed the zone limit, fall through to the kmem module.
*/
#define MIN_CHUNK_SIZE 8 /* in bytes */
#define MIN_CHUNK_MASK (MIN_CHUNK_SIZE - 1)
/*
* Array of descriptors that describe the contents of each page
*/
#define PAGE_TYPE_FREE 0x00
#define PAGE_TYPE_SMALL 0x01
#define PAGE_TYPE_LARGE 0x02
struct memusage
{
rt_uint32_t type: 2 ; /* page type */
rt_uint32_t size: 30; /* pages allocated or offset from zone */
};
static struct memusage *memusage = RT_NULL;
#define btokup(addr) \
(&memusage[((rt_ubase_t)(addr) - heap_start) >> RT_MM_PAGE_BITS])
static rt_ubase_t heap_start, heap_end;
/* page allocator */
struct rt_page_head
{
struct rt_page_head *next; /* next valid page */
rt_size_t page; /* number of page */
/* dummy */
char dummy[RT_MM_PAGE_SIZE - (sizeof(struct rt_page_head *) + sizeof(rt_size_t))];
};
static struct rt_page_head *rt_page_list;
static struct rt_semaphore heap_sem;
void *rt_page_alloc(rt_size_t npages)
{
struct rt_page_head *b, *n;
struct rt_page_head **prev;
if (npages == 0)
return RT_NULL;
/* lock heap */
rt_sem_take(&heap_sem, RT_WAITING_FOREVER);
for (prev = &rt_page_list; (b = *prev) != RT_NULL; prev = &(b->next))
{
if (b->page > npages)
{
/* splite pages */
n = b + npages;
n->next = b->next;
n->page = b->page - npages;
*prev = n;
break;
}
if (b->page == npages)
{
/* this node fit, remove this node */
*prev = b->next;
break;
}
}
/* unlock heap */
rt_sem_release(&heap_sem);
return b;
}
void rt_page_free(void *addr, rt_size_t npages)
{
struct rt_page_head *b, *n;
struct rt_page_head **prev;
RT_ASSERT(addr != RT_NULL);
RT_ASSERT((rt_ubase_t)addr % RT_MM_PAGE_SIZE == 0);
RT_ASSERT(npages != 0);
n = (struct rt_page_head *)addr;
/* lock heap */
rt_sem_take(&heap_sem, RT_WAITING_FOREVER);
for (prev = &rt_page_list; (b = *prev) != RT_NULL; prev = &(b->next))
{
RT_ASSERT(b->page > 0);
RT_ASSERT(b > n || b + b->page <= n);
if (b + b->page == n)
{
if (b + (b->page += npages) == b->next)
{
b->page += b->next->page;
b->next = b->next->next;
}
goto _return;
}
if (b == n + npages)
{
n->page = b->page + npages;
n->next = b->next;
*prev = n;
goto _return;
}
if (b > n + npages)
break;
}
n->page = npages;
n->next = b;
*prev = n;
_return:
/* unlock heap */
rt_sem_release(&heap_sem);
}
/*
* Initialize the page allocator
*/
static void rt_page_init(void *addr, rt_size_t npages)
{
RT_ASSERT(addr != RT_NULL);
RT_ASSERT(npages != 0);
rt_page_list = RT_NULL;
rt_page_free(addr, npages);
}
/**
* @ingroup SystemInit
*
* This function will init system heap
*
* @param begin_addr the beginning address of system page
* @param end_addr the end address of system page
*/
void rt_system_heap_init(void *begin_addr, void *end_addr)
{
rt_uint32_t limsize, npages;
RT_DEBUG_NOT_IN_INTERRUPT;
/* align begin and end addr to page */
heap_start = RT_ALIGN((rt_ubase_t)begin_addr, RT_MM_PAGE_SIZE);
heap_end = RT_ALIGN_DOWN((rt_ubase_t)end_addr, RT_MM_PAGE_SIZE);
if (heap_start >= heap_end)
{
rt_kprintf("rt_system_heap_init, wrong address[0x%x - 0x%x]\n",
(rt_ubase_t)begin_addr, (rt_ubase_t)end_addr);
return;
}
limsize = heap_end - heap_start;
npages = limsize / RT_MM_PAGE_SIZE;
/* initialize heap semaphore */
rt_sem_init(&heap_sem, "heap", 1, RT_IPC_FLAG_FIFO);
RT_DEBUG_LOG(RT_DEBUG_SLAB, ("heap[0x%x - 0x%x], size 0x%x, 0x%x pages\n",
heap_start, heap_end, limsize, npages));
/* init pages */
rt_page_init((void *)heap_start, npages);
/* calculate zone size */
zone_size = ZALLOC_MIN_ZONE_SIZE;
while (zone_size < ZALLOC_MAX_ZONE_SIZE && (zone_size << 1) < (limsize / 1024))
zone_size <<= 1;
zone_limit = zone_size / 4;
if (zone_limit > ZALLOC_ZONE_LIMIT)
zone_limit = ZALLOC_ZONE_LIMIT;
zone_page_cnt = zone_size / RT_MM_PAGE_SIZE;
RT_DEBUG_LOG(RT_DEBUG_SLAB, ("zone size 0x%x, zone page count 0x%x\n",
zone_size, zone_page_cnt));
/* allocate memusage array */
limsize = npages * sizeof(struct memusage);
limsize = RT_ALIGN(limsize, RT_MM_PAGE_SIZE);
memusage = rt_page_alloc(limsize / RT_MM_PAGE_SIZE);
RT_DEBUG_LOG(RT_DEBUG_SLAB, ("memusage 0x%x, size 0x%x\n",
(rt_ubase_t)memusage, limsize));
}
/*
* Calculate the zone index for the allocation request size and set the
* allocation request size to that particular zone's chunk size.
*/
rt_inline int zoneindex(rt_size_t *bytes)
{
/* unsigned for shift opt */
rt_ubase_t n = (rt_ubase_t)(*bytes);
if (n < 128)
{
*bytes = n = (n + 7) & ~7;
/* 8 byte chunks, 16 zones */
return (n / 8 - 1);
}
if (n < 256)
{
*bytes = n = (n + 15) & ~15;
return (n / 16 + 7);
}
if (n < 8192)
{
if (n < 512)
{
*bytes = n = (n + 31) & ~31;
return (n / 32 + 15);
}
if (n < 1024)
{
*bytes = n = (n + 63) & ~63;
return (n / 64 + 23);
}
if (n < 2048)
{
*bytes = n = (n + 127) & ~127;
return (n / 128 + 31);
}
if (n < 4096)
{
*bytes = n = (n + 255) & ~255;
return (n / 256 + 39);
}
*bytes = n = (n + 511) & ~511;
return (n / 512 + 47);
}
if (n < 16384)
{
*bytes = n = (n + 1023) & ~1023;
return (n / 1024 + 55);
}
rt_kprintf("Unexpected byte count %d", n);
return 0;
}
/**
* @addtogroup MM
*/
/**@{*/
/**
* This function will allocate a block from system heap memory.
* - If the nbytes is less than zero,
* or
* - If there is no nbytes sized memory valid in system,
* the RT_NULL is returned.
*
* @param size the size of memory to be allocated
*
* @return the allocated memory
*/
void *rt_malloc(rt_size_t size)
{
slab_zone *z;
rt_int32_t zi;
slab_chunk *chunk;
struct memusage *kup;
/* zero size, return RT_NULL */
if (size == 0)
return RT_NULL;
/*
* Handle large allocations directly. There should not be very many of
* these so performance is not a big issue.
*/
if (size >= zone_limit)
{
size = RT_ALIGN(size, RT_MM_PAGE_SIZE);
chunk = rt_page_alloc(size >> RT_MM_PAGE_BITS);
if (chunk == RT_NULL)
return RT_NULL;
/* set kup */
kup = btokup(chunk);
kup->type = PAGE_TYPE_LARGE;
kup->size = size >> RT_MM_PAGE_BITS;
RT_DEBUG_LOG(RT_DEBUG_SLAB,
("malloc a large memory 0x%x, page cnt %d, kup %d\n",
size,
size >> RT_MM_PAGE_BITS,
((rt_ubase_t)chunk - heap_start) >> RT_MM_PAGE_BITS));
/* lock heap */
rt_sem_take(&heap_sem, RT_WAITING_FOREVER);
#ifdef RT_MEM_STATS
used_mem += size;
if (used_mem > max_mem)
max_mem = used_mem;
#endif
goto done;
}
/* lock heap */
rt_sem_take(&heap_sem, RT_WAITING_FOREVER);
/*
* Attempt to allocate out of an existing zone. First try the free list,
* then allocate out of unallocated space. If we find a good zone move
* it to the head of the list so later allocations find it quickly
* (we might have thousands of zones in the list).
*
* Note: zoneindex() will panic of size is too large.
*/
zi = zoneindex(&size);
RT_ASSERT(zi < NZONES);
RT_DEBUG_LOG(RT_DEBUG_SLAB, ("try to malloc 0x%x on zone: %d\n", size, zi));
if ((z = zone_array[zi]) != RT_NULL)
{
RT_ASSERT(z->z_nfree > 0);
/* Remove us from the zone_array[] when we become empty */
if (--z->z_nfree == 0)
{
zone_array[zi] = z->z_next;
z->z_next = RT_NULL;
}
/*
* No chunks are available but nfree said we had some memory, so
* it must be available in the never-before-used-memory area
* governed by uindex. The consequences are very serious if our zone
* got corrupted so we use an explicit rt_kprintf rather then a KASSERT.
*/
if (z->z_uindex + 1 != z->z_nmax)
{
z->z_uindex = z->z_uindex + 1;
chunk = (slab_chunk *)(z->z_baseptr + z->z_uindex * size);
}
else
{
/* find on free chunk list */
chunk = z->z_freechunk;
/* remove this chunk from list */
z->z_freechunk = z->z_freechunk->c_next;
}
#ifdef RT_MEM_STATS
used_mem += z->z_chunksize;
if (used_mem > max_mem)
max_mem = used_mem;
#endif
goto done;
}
/*
* If all zones are exhausted we need to allocate a new zone for this
* index.
*
* At least one subsystem, the tty code (see CROUND) expects power-of-2
* allocations to be power-of-2 aligned. We maintain compatibility by
* adjusting the base offset below.
*/
{
rt_int32_t off;
if ((z = zone_free) != RT_NULL)
{
/* remove zone from free zone list */
zone_free = z->z_next;
-- zone_free_cnt;
}
else
{
/* unlock heap, since page allocator will think about lock */
rt_sem_release(&heap_sem);
/* allocate a zone from page */
z = rt_page_alloc(zone_size / RT_MM_PAGE_SIZE);
if (z == RT_NULL)
{
chunk = RT_NULL;
goto __exit;
}
/* lock heap */
rt_sem_take(&heap_sem, RT_WAITING_FOREVER);
RT_DEBUG_LOG(RT_DEBUG_SLAB, ("alloc a new zone: 0x%x\n",
(rt_ubase_t)z));
/* set message usage */
for (off = 0, kup = btokup(z); off < zone_page_cnt; off ++)
{
kup->type = PAGE_TYPE_SMALL;
kup->size = off;
kup ++;
}
}
/* clear to zero */
rt_memset(z, 0, sizeof(slab_zone));
/* offset of slab zone struct in zone */
off = sizeof(slab_zone);
/*
* Guarentee power-of-2 alignment for power-of-2-sized chunks.
* Otherwise just 8-byte align the data.
*/
if ((size | (size - 1)) + 1 == (size << 1))
off = (off + size - 1) & ~(size - 1);
else
off = (off + MIN_CHUNK_MASK) & ~MIN_CHUNK_MASK;
z->z_magic = ZALLOC_SLAB_MAGIC;
z->z_zoneindex = zi;
z->z_nmax = (zone_size - off) / size;
z->z_nfree = z->z_nmax - 1;
z->z_baseptr = (rt_uint8_t *)z + off;
z->z_uindex = 0;
z->z_chunksize = size;
chunk = (slab_chunk *)(z->z_baseptr + z->z_uindex * size);
/* link to zone array */
z->z_next = zone_array[zi];
zone_array[zi] = z;
#ifdef RT_MEM_STATS
used_mem += z->z_chunksize;
if (used_mem > max_mem)
max_mem = used_mem;
#endif
}
done:
rt_sem_release(&heap_sem);
RT_OBJECT_HOOK_CALL(rt_malloc_hook, ((char *)chunk, size));
__exit:
return chunk;
}
RTM_EXPORT(rt_malloc);
/**
* This function will change the size of previously allocated memory block.
*
* @param ptr the previously allocated memory block
* @param size the new size of memory block
*
* @return the allocated memory
*/
void *rt_realloc(void *ptr, rt_size_t size)
{
void *nptr;
slab_zone *z;
struct memusage *kup;
if (ptr == RT_NULL)
return rt_malloc(size);
if (size == 0)
{
rt_free(ptr);
return RT_NULL;
}
/*
* Get the original allocation's zone. If the new request winds up
* using the same chunk size we do not have to do anything.
*/
kup = btokup((rt_ubase_t)ptr & ~RT_MM_PAGE_MASK);
if (kup->type == PAGE_TYPE_LARGE)
{
rt_size_t osize;
osize = kup->size << RT_MM_PAGE_BITS;
if ((nptr = rt_malloc(size)) == RT_NULL)
return RT_NULL;
rt_memcpy(nptr, ptr, size > osize ? osize : size);
rt_free(ptr);
return nptr;
}
else if (kup->type == PAGE_TYPE_SMALL)
{
z = (slab_zone *)(((rt_ubase_t)ptr & ~RT_MM_PAGE_MASK) -
kup->size * RT_MM_PAGE_SIZE);
RT_ASSERT(z->z_magic == ZALLOC_SLAB_MAGIC);
zoneindex(&size);
if (z->z_chunksize == size)
return (ptr); /* same chunk */
/*
* Allocate memory for the new request size. Note that zoneindex has
* already adjusted the request size to the appropriate chunk size, which
* should optimize our bcopy(). Then copy and return the new pointer.
*/
if ((nptr = rt_malloc(size)) == RT_NULL)
return RT_NULL;
rt_memcpy(nptr, ptr, size > z->z_chunksize ? z->z_chunksize : size);
rt_free(ptr);
return nptr;
}
return RT_NULL;
}
RTM_EXPORT(rt_realloc);
/**
* This function will contiguously allocate enough space for count objects
* that are size bytes of memory each and returns a pointer to the allocated
* memory.
*
* The allocated memory is filled with bytes of value zero.
*
* @param count number of objects to allocate
* @param size size of the objects to allocate
*
* @return pointer to allocated memory / NULL pointer if there is an error
*/
void *rt_calloc(rt_size_t count, rt_size_t size)
{
void *p;
/* allocate 'count' objects of size 'size' */
p = rt_malloc(count * size);
/* zero the memory */
if (p)
rt_memset(p, 0, count * size);
return p;
}
RTM_EXPORT(rt_calloc);
/**
* This function will release the previous allocated memory block by rt_malloc.
* The released memory block is taken back to system heap.
*
* @param ptr the address of memory which will be released
*/
void rt_free(void *ptr)
{
slab_zone *z;
slab_chunk *chunk;
struct memusage *kup;
/* free a RT_NULL pointer */
if (ptr == RT_NULL)
return ;
RT_OBJECT_HOOK_CALL(rt_free_hook, (ptr));
/* get memory usage */
#if RT_DEBUG_SLAB
{
rt_ubase_t addr = ((rt_ubase_t)ptr & ~RT_MM_PAGE_MASK);
RT_DEBUG_LOG(RT_DEBUG_SLAB,
("free a memory 0x%x and align to 0x%x, kup index %d\n",
(rt_ubase_t)ptr,
(rt_ubase_t)addr,
((rt_ubase_t)(addr) - heap_start) >> RT_MM_PAGE_BITS));
}
#endif
kup = btokup((rt_ubase_t)ptr & ~RT_MM_PAGE_MASK);
/* release large allocation */
if (kup->type == PAGE_TYPE_LARGE)
{
rt_ubase_t size;
/* lock heap */
rt_sem_take(&heap_sem, RT_WAITING_FOREVER);
/* clear page counter */
size = kup->size;
kup->size = 0;
#ifdef RT_MEM_STATS
used_mem -= size * RT_MM_PAGE_SIZE;
#endif
rt_sem_release(&heap_sem);
RT_DEBUG_LOG(RT_DEBUG_SLAB,
("free large memory block 0x%x, page count %d\n",
(rt_ubase_t)ptr, size));
/* free this page */
rt_page_free(ptr, size);
return;
}
/* lock heap */
rt_sem_take(&heap_sem, RT_WAITING_FOREVER);
/* zone case. get out zone. */
z = (slab_zone *)(((rt_ubase_t)ptr & ~RT_MM_PAGE_MASK) -
kup->size * RT_MM_PAGE_SIZE);
RT_ASSERT(z->z_magic == ZALLOC_SLAB_MAGIC);
chunk = (slab_chunk *)ptr;
chunk->c_next = z->z_freechunk;
z->z_freechunk = chunk;
#ifdef RT_MEM_STATS
used_mem -= z->z_chunksize;
#endif
/*
* Bump the number of free chunks. If it becomes non-zero the zone
* must be added back onto the appropriate list.
*/
if (z->z_nfree++ == 0)
{
z->z_next = zone_array[z->z_zoneindex];
zone_array[z->z_zoneindex] = z;
}
/*
* If the zone becomes totally free, and there are other zones we
* can allocate from, move this zone to the FreeZones list. Since
* this code can be called from an IPI callback, do *NOT* try to mess
* with kernel_map here. Hysteresis will be performed at malloc() time.
*/
if (z->z_nfree == z->z_nmax &&
(z->z_next || zone_array[z->z_zoneindex] != z))
{
slab_zone **pz;
RT_DEBUG_LOG(RT_DEBUG_SLAB, ("free zone 0x%x\n",
(rt_ubase_t)z, z->z_zoneindex));
/* remove zone from zone array list */
for (pz = &zone_array[z->z_zoneindex]; z != *pz; pz = &(*pz)->z_next)
;
*pz = z->z_next;
/* reset zone */
z->z_magic = -1;
/* insert to free zone list */
z->z_next = zone_free;
zone_free = z;
++ zone_free_cnt;
/* release zone to page allocator */
if (zone_free_cnt > ZONE_RELEASE_THRESH)
{
register rt_base_t i;
z = zone_free;
zone_free = z->z_next;
-- zone_free_cnt;
/* set message usage */
for (i = 0, kup = btokup(z); i < zone_page_cnt; i ++)
{
kup->type = PAGE_TYPE_FREE;
kup->size = 0;
kup ++;
}
/* unlock heap */
rt_sem_release(&heap_sem);
/* release pages */
rt_page_free(z, zone_size / RT_MM_PAGE_SIZE);
return;
}
}
/* unlock heap */
rt_sem_release(&heap_sem);
}
RTM_EXPORT(rt_free);
#ifdef RT_MEM_STATS
void rt_memory_info(rt_uint32_t *total,
rt_uint32_t *used,
rt_uint32_t *max_used)
{
if (total != RT_NULL)
*total = heap_end - heap_start;
if (used != RT_NULL)
*used = used_mem;
if (max_used != RT_NULL)
*max_used = max_mem;
}
#ifdef RT_USING_FINSH
#include <finsh.h>
void list_mem(void)
{
rt_kprintf("total memory: %d\n", heap_end - heap_start);
rt_kprintf("used memory : %d\n", used_mem);
rt_kprintf("maximum allocated memory: %d\n", max_mem);
}
FINSH_FUNCTION_EXPORT(list_mem, list memory usage information)
#endif
#endif
/**@}*/
#endif
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