303 lines
8.3 KiB
C
303 lines
8.3 KiB
C
/*
|
|
* This module derived from code donated to the FreeBSD Project by
|
|
* Matthew Dillon <dillon@backplane.com>
|
|
*
|
|
* Copyright (c) 1998 The FreeBSD Project
|
|
* All rights reserved.
|
|
*
|
|
* 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.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
|
|
*
|
|
* $Id: zalloc.c,v 1.3 1998/09/26 10:48:50 dfr Exp $
|
|
*/
|
|
|
|
/*
|
|
* LIB/MEMORY/ZALLOC.C - self contained low-overhead memory pool/allocation
|
|
* subsystem
|
|
*
|
|
* This subsystem implements memory pools and memory allocation
|
|
* routines.
|
|
*
|
|
* Pools are managed via a linked list of 'free' areas. Allocating
|
|
* memory creates holes in the freelist, freeing memory fills them.
|
|
* Since the freelist consists only of free memory areas, it is possible
|
|
* to allocate the entire pool without incuring any structural overhead.
|
|
*
|
|
* The system works best when allocating similarly-sized chunks of
|
|
* memory. Care must be taken to avoid fragmentation when
|
|
* allocating/deallocating dissimilar chunks.
|
|
*
|
|
* When a memory pool is first allocated, the entire pool is marked as
|
|
* allocated. This is done mainly because we do not want to modify any
|
|
* portion of a pool's data area until we are given permission. The
|
|
* caller must explicitly deallocate portions of the pool to make them
|
|
* available.
|
|
*
|
|
* z[n]xalloc() works like z[n]alloc() but the allocation is made from
|
|
* within the specified address range. If the segment could not be
|
|
* allocated, NULL is returned. WARNING! The address range will be
|
|
* aligned to an 8 or 16 byte boundry depending on the cpu so if you
|
|
* give an unaligned address range, unexpected results may occur.
|
|
*
|
|
* If a standard allocation fails, the reclaim function will be called
|
|
* to recover some space. This usually causes other portions of the
|
|
* same pool to be released. Memory allocations at this low level
|
|
* should not block but you can do that too in your reclaim function
|
|
* if you want. Reclaim does not function when z[n]xalloc() is used,
|
|
* only for z[n]alloc().
|
|
*
|
|
* Allocation and frees of 0 bytes are valid operations.
|
|
*/
|
|
|
|
#include "zalloc_defs.h"
|
|
|
|
/*
|
|
* znalloc() - allocate memory (without zeroing) from pool. Call reclaim
|
|
* and retry if appropriate, return NULL if unable to allocate
|
|
* memory.
|
|
*/
|
|
|
|
void *
|
|
znalloc(MemPool *mp, iaddr_t bytes)
|
|
{
|
|
/*
|
|
* align according to pool object size (can be 0). This is
|
|
* inclusive of the MEMNODE_SIZE_MASK minimum alignment.
|
|
*
|
|
*/
|
|
bytes = (bytes + MEMNODE_SIZE_MASK) & ~MEMNODE_SIZE_MASK;
|
|
|
|
if (bytes == 0)
|
|
return((void *)-1);
|
|
|
|
/*
|
|
* locate freelist entry big enough to hold the object. If all objects
|
|
* are the same size, this is a constant-time function.
|
|
*/
|
|
|
|
if (bytes <= mp->mp_Size - mp->mp_Used) {
|
|
MemNode **pmn;
|
|
MemNode *mn;
|
|
|
|
for (pmn = &mp->mp_First; (mn=*pmn) != NULL; pmn = &mn->mr_Next) {
|
|
if (bytes > mn->mr_Bytes)
|
|
continue;
|
|
|
|
/*
|
|
* Cut a chunk of memory out of the beginning of this
|
|
* block and fixup the link appropriately.
|
|
*/
|
|
|
|
{
|
|
char *ptr = (char *)mn;
|
|
|
|
if (mn->mr_Bytes == bytes) {
|
|
*pmn = mn->mr_Next;
|
|
} else {
|
|
mn = (MemNode *)((char *)mn + bytes);
|
|
mn->mr_Next = ((MemNode *)ptr)->mr_Next;
|
|
mn->mr_Bytes = ((MemNode *)ptr)->mr_Bytes - bytes;
|
|
*pmn = mn;
|
|
}
|
|
mp->mp_Used += bytes;
|
|
return(ptr);
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Memory pool is full, return NULL.
|
|
*/
|
|
|
|
return(NULL);
|
|
}
|
|
|
|
/*
|
|
* zfree() - free previously allocated memory
|
|
*/
|
|
|
|
void
|
|
zfree(MemPool *mp, void *ptr, iaddr_t bytes)
|
|
{
|
|
/*
|
|
* align according to pool object size (can be 0). This is
|
|
* inclusive of the MEMNODE_SIZE_MASK minimum alignment.
|
|
*/
|
|
bytes = (bytes + MEMNODE_SIZE_MASK) & ~MEMNODE_SIZE_MASK;
|
|
|
|
if (bytes == 0)
|
|
return;
|
|
|
|
/*
|
|
* panic if illegal pointer
|
|
*/
|
|
|
|
if ((char *)ptr < (char *)mp->mp_Base ||
|
|
(char *)ptr + bytes > (char *)mp->mp_End ||
|
|
((iaddr_t)ptr & MEMNODE_SIZE_MASK) != 0)
|
|
panic("zfree(%p,%d): wild pointer", ptr, bytes);
|
|
|
|
/*
|
|
* free the segment
|
|
*/
|
|
|
|
{
|
|
MemNode **pmn;
|
|
MemNode *mn;
|
|
|
|
mp->mp_Used -= bytes;
|
|
|
|
for (pmn = &mp->mp_First; (mn = *pmn) != NULL; pmn = &mn->mr_Next) {
|
|
/*
|
|
* If area between last node and current node
|
|
* - check range
|
|
* - check merge with next area
|
|
* - check merge with previous area
|
|
*/
|
|
if ((char *)ptr <= (char *)mn) {
|
|
/*
|
|
* range check
|
|
*/
|
|
if ((char *)ptr + bytes > (char *)mn)
|
|
panic("zfree(%p,%d): corrupt memlist1",ptr, bytes);
|
|
|
|
/*
|
|
* merge against next area or create independant area
|
|
*/
|
|
|
|
if ((char *)ptr + bytes == (char *)mn) {
|
|
((MemNode *)ptr)->mr_Next = mn->mr_Next;
|
|
((MemNode *)ptr)->mr_Bytes= bytes + mn->mr_Bytes;
|
|
} else {
|
|
((MemNode *)ptr)->mr_Next = mn;
|
|
((MemNode *)ptr)->mr_Bytes= bytes;
|
|
}
|
|
*pmn = mn = (MemNode *)ptr;
|
|
|
|
/*
|
|
* merge against previous area (if there is a previous
|
|
* area).
|
|
*/
|
|
|
|
if (pmn != &mp->mp_First) {
|
|
if ((char*)pmn + ((MemNode*)pmn)->mr_Bytes == (char*)ptr) {
|
|
((MemNode *)pmn)->mr_Next = mn->mr_Next;
|
|
((MemNode *)pmn)->mr_Bytes += mn->mr_Bytes;
|
|
mn = (MemNode *)pmn;
|
|
}
|
|
}
|
|
return;
|
|
/* NOT REACHED */
|
|
}
|
|
if ((char *)ptr < (char *)mn + mn->mr_Bytes)
|
|
panic("zfree(%p,%d): corrupt memlist2", ptr, bytes);
|
|
}
|
|
/*
|
|
* We are beyond the last MemNode, append new MemNode. Merge against
|
|
* previous area if possible.
|
|
*/
|
|
if (pmn == &mp->mp_First ||
|
|
(char *)pmn + ((MemNode *)pmn)->mr_Bytes != (char *)ptr
|
|
) {
|
|
((MemNode *)ptr)->mr_Next = NULL;
|
|
((MemNode *)ptr)->mr_Bytes = bytes;
|
|
*pmn = (MemNode *)ptr;
|
|
mn = (MemNode *)ptr;
|
|
} else {
|
|
((MemNode *)pmn)->mr_Bytes += bytes;
|
|
mn = (MemNode *)pmn;
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* zextendPool() - extend memory pool to cover additional space.
|
|
*
|
|
* Note: the added memory starts out as allocated, you
|
|
* must free it to make it available to the memory subsystem.
|
|
*
|
|
* Note: mp_Size may not reflect (mp_End - mp_Base) range
|
|
* due to other parts of the system doing their own sbrk()
|
|
* calls.
|
|
*/
|
|
|
|
void
|
|
zextendPool(MemPool *mp, void *base, iaddr_t bytes)
|
|
{
|
|
if (mp->mp_Size == 0) {
|
|
mp->mp_Base = base;
|
|
mp->mp_Used = bytes;
|
|
mp->mp_End = (char *)base + bytes;
|
|
} else {
|
|
void *pend = (char *)mp->mp_Base + mp->mp_Size;
|
|
|
|
if (base < mp->mp_Base) {
|
|
/* mp->mp_Size += (char *)mp->mp_Base - (char *)base; */
|
|
mp->mp_Used += (char *)mp->mp_Base - (char *)base;
|
|
mp->mp_Base = base;
|
|
}
|
|
base = (char *)base + bytes;
|
|
if (base > pend) {
|
|
/* mp->mp_Size += (char *)base - (char *)pend; */
|
|
mp->mp_Used += (char *)base - (char *)pend;
|
|
mp->mp_End = (char *)base;
|
|
}
|
|
}
|
|
mp->mp_Size += bytes;
|
|
}
|
|
|
|
#ifdef ZALLOCDEBUG
|
|
|
|
void
|
|
zallocstats(MemPool *mp)
|
|
{
|
|
int abytes = 0;
|
|
int hbytes = 0;
|
|
int fcount = 0;
|
|
MemNode *mn;
|
|
|
|
printf("%d bytes reserved", (int) mp->mp_Size);
|
|
|
|
mn = mp->mp_First;
|
|
|
|
if ((void *)mn != (void *)mp->mp_Base) {
|
|
abytes += (char *)mn - (char *)mp->mp_Base;
|
|
}
|
|
|
|
while (mn) {
|
|
if ((char *)mn + mn->mr_Bytes != mp->mp_End) {
|
|
hbytes += mn->mr_Bytes;
|
|
++fcount;
|
|
}
|
|
if (mn->mr_Next)
|
|
abytes += (char *)mn->mr_Next - ((char *)mn + mn->mr_Bytes);
|
|
mn = mn->mr_Next;
|
|
}
|
|
printf(" %d bytes allocated\n%d fragments (%d bytes fragmented)\n",
|
|
abytes,
|
|
fcount,
|
|
hbytes
|
|
);
|
|
}
|
|
|
|
#endif
|
|
|