224 lines
6.4 KiB
C
224 lines
6.4 KiB
C
/* $NetBSD: subr_rmap.c,v 1.16 1998/08/18 18:16:30 thorpej Exp $ */
|
|
|
|
/*
|
|
* Copyright (C) 1992, 1994 Wolfgang Solfrank.
|
|
* Copyright (C) 1992, 1994 TooLs GmbH.
|
|
* 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.
|
|
* 3. All advertising materials mentioning features or use of this software
|
|
* must display the following acknowledgement:
|
|
* This product includes software developed by TooLs GmbH.
|
|
* 4. The name of TooLs GmbH may not be used to endorse or promote products
|
|
* derived from this software without specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``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 TOOLS GMBH 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 <sys/param.h>
|
|
#include <sys/map.h>
|
|
#include <sys/systm.h>
|
|
|
|
/*
|
|
* Resource allocation map handling.
|
|
*
|
|
* Code derived from usage in ../vm/swap_pager.c and ../vm/vm_swap.c
|
|
* and the (corrected due to the above) comments in ../sys/map.h.
|
|
*
|
|
* Assume small maps. Keep it sorted by addr with free mapents last.
|
|
*/
|
|
|
|
/*
|
|
* Initialize a resource map.
|
|
* The map is called "name", and has nelem-1
|
|
* slots (the first one is reused to describe the map).
|
|
* Initially it manages the address range starting at
|
|
* addr with size size.
|
|
*/
|
|
void
|
|
rminit(mp, size, addr, name, nelem)
|
|
struct map *mp;
|
|
long size, addr;
|
|
char *name;
|
|
int nelem;
|
|
{
|
|
struct mapent *ep;
|
|
|
|
/* mapsize had better be at least 2 */
|
|
if (nelem < 2 || addr <= 0 || size < 0)
|
|
panic("rminit %s",name);
|
|
mp->m_name = name;
|
|
mp->m_limit = (struct mapent *)mp + nelem;
|
|
|
|
/* initially the first entry describes all free space */
|
|
ep = (struct mapent *)mp + 1;
|
|
ep->m_size = size;
|
|
ep->m_addr = addr;
|
|
/* the remaining slots are unused (indicated by m_addr == 0) */
|
|
while (++ep < mp->m_limit)
|
|
ep->m_addr = 0;
|
|
}
|
|
|
|
/*
|
|
* Allocate space out of a resource map.
|
|
* Try to find an exact match. Otherwise get the space from
|
|
* the smallest slot.
|
|
*/
|
|
long
|
|
rmalloc(mp, size)
|
|
struct map *mp;
|
|
long size;
|
|
{
|
|
struct mapent *ep, *fp;
|
|
long addr;
|
|
|
|
/* first check arguments */
|
|
if (size < 0)
|
|
panic("rmalloc %s", mp->m_name);
|
|
if (!size)
|
|
return 0;
|
|
|
|
fp = 0;
|
|
/* try to find the smallest fit */
|
|
for (ep = (struct mapent *)mp + 1; ep < mp->m_limit; ep++) {
|
|
if (!ep->m_addr) {
|
|
/* unused slots terminate the list */
|
|
break;
|
|
}
|
|
if (ep->m_size == size) {
|
|
/* found exact match, use it, ... */
|
|
addr = ep->m_addr;
|
|
/* copy over the remaining slots ... */
|
|
memmove(ep, ep + 1, (char *)mp->m_limit - (char *)(ep + 1));
|
|
/* and mark the last slot as unused */
|
|
mp->m_limit[-1].m_addr = 0;
|
|
return addr;
|
|
}
|
|
if (ep->m_size > size
|
|
&& (!fp
|
|
|| fp->m_size > ep->m_size)) {
|
|
/* found a larger slot, remember the smallest of these */
|
|
fp = ep;
|
|
}
|
|
}
|
|
if (fp) {
|
|
/* steal requested size from a larger slot */
|
|
addr = fp->m_addr;
|
|
fp->m_addr += size;
|
|
fp->m_size -= size;
|
|
return addr;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Free (or add) space to a resource map.
|
|
* If there aren't enough slots in the map to describe the free space,
|
|
* drop the smallest slot.
|
|
*/
|
|
void
|
|
rmfree(mp, size, addr)
|
|
struct map *mp;
|
|
long size, addr;
|
|
{
|
|
struct mapent *ep, *fp;
|
|
|
|
/* first check arguments */
|
|
if (size <= 0 || addr <= 0)
|
|
panic("rmfree %s", mp->m_name);
|
|
|
|
while (1) {
|
|
fp = 0;
|
|
|
|
for (ep = (struct mapent *)mp + 1; ep < mp->m_limit; ep++) {
|
|
if (!ep->m_addr) {
|
|
/* unused slots terminate the list */
|
|
break;
|
|
}
|
|
if (ep->m_addr + ep->m_size == addr) {
|
|
/* this slot ends just with the address to free */
|
|
ep->m_size += size; /* increase size of slot */
|
|
if (ep < mp->m_limit
|
|
&& ep[1].m_addr
|
|
&& (addr += size) >= ep[1].m_addr) {
|
|
if (addr > ep[1].m_addr) /* overlapping frees? */
|
|
panic("rmfree %s", mp->m_name);
|
|
/* the next slot is now contiguous, so join ... */
|
|
ep->m_size += ep[1].m_size;
|
|
memmove(ep + 1, ep + 2,
|
|
(char *)mp->m_limit - (char *)(ep + 2));
|
|
/* and mark the last slot as unused */
|
|
mp->m_limit[-1].m_addr = 0;
|
|
}
|
|
return;
|
|
}
|
|
if (addr + size == ep->m_addr) {
|
|
/* range to free is contiguous to this slot */
|
|
ep->m_addr = addr;
|
|
ep->m_size += size;
|
|
return;
|
|
}
|
|
if (addr < ep->m_addr
|
|
&& !mp->m_limit[-1].m_addr) {
|
|
/* insert entry into list keeping it sorted on m_addr */
|
|
memmove(ep + 1, ep, (char *)(mp->m_limit - 1) - (char *)ep);
|
|
ep->m_addr = addr;
|
|
ep->m_size = size;
|
|
return;
|
|
}
|
|
if (!fp || fp->m_size > ep->m_size) {
|
|
/* find the slot with the smallest size to drop */
|
|
fp = ep;
|
|
}
|
|
}
|
|
if (ep != (struct mapent *)mp + 1
|
|
&& ep[-1].m_addr + ep[-1].m_size == addr) {
|
|
/* range to free is contiguous to the last used slot */
|
|
(--ep)->m_size += size;
|
|
return;
|
|
}
|
|
if (ep != mp->m_limit) {
|
|
/* use empty slot for range to free */
|
|
ep->m_addr = addr;
|
|
ep->m_size = size;
|
|
return;
|
|
}
|
|
/*
|
|
* The range to free isn't contiguous to any free space,
|
|
* and there is no free slot available, so we are sorry,
|
|
* but we have to loose some space.
|
|
* fp points to the slot with the smallest size
|
|
*/
|
|
if (fp->m_size > size) {
|
|
/* range to free is smaller, so drop that */
|
|
printf("rmfree: map '%s' loses space (%ld)\n",
|
|
mp->m_name, size);
|
|
return;
|
|
} else {
|
|
/* drop the smallest slot in the list */
|
|
printf("rmfree: map '%s' loses space (%ld)\n",
|
|
mp->m_name, fp->m_size);
|
|
memmove(fp, fp + 1,
|
|
(char *)(mp->m_limit - 1) - (char *)fp);
|
|
mp->m_limit[-1].m_addr = 0;
|
|
/* now retry */
|
|
}
|
|
}
|
|
}
|