[unix-history] / usr / src / sys / kern / subr_rmap.c.sav

/*	subr_rmap.c.sav	4.6	82/10/10	*/

#include "../h/param.h"
#include "../h/systm.h"
#include "../h/map.h"
#include "../h/dir.h"
#include "../h/user.h"
#include "../h/proc.h"
#include "../h/text.h"

/*
 * Resource map handling routines.
 *
 * A resource map is an array of structures each
 * of which describes a segment of the address space of an available
 * resource.  The segments are described by their base address and
 * length, and sorted in address order.  Each resource map has a fixed
 * maximum number of segments allowed.  Resources are allocated
 * by taking part or all of one of the segments of the map.
 *
 * Returning of resources will require another segment if
 * the returned resources are not adjacent in the address
 * space to an existing segment.  If the return of a segment
 * would require a slot which is not available, then one of
 * the resource map segments is discarded after a warning is printed.
 * Returning of resources may also cause the map to collapse
 * by coalescing two existing segments and the returned space
 * into a single segment.  In this case the resource map is
 * made smaller by copying together to fill the resultant gap.
 *
 * N.B.: the current implementation uses a dense array and does
 * not admit the value ``0'' as a legal address, since that is used
 * as a delimiter.
 */

/*
 * Initialize map mp to have (mapsize-2) segments
 * and to be called ``name'', which we print if
 * the slots become so fragmented that we lose space.
 * The map itself is initialized with size elements free
 * starting at addr.
 */
rminit(mp, size, addr, name, mapsize)
	register struct map *mp;
	int size, addr;
	char *name;
	int mapsize;
{
	register struct mapent *ep = (struct mapent *)(mp+1);

	mp->m_name = name;
/* N.B.: WE ASSUME HERE THAT sizeof (struct map) == sizeof (struct mapent) */
	/*
	 * One of the mapsize slots is taken by the map structure,
	 * segments has size 0 and addr 0, and acts as a delimiter.
	 * We insure that we never use segments past the end of
	 * the array which is given by mp->m_limit.
	 * Instead, when excess segments occur we discard some resources.
	 */
	mp->m_limit = (struct mapent *)&mp[mapsize];
	/*
	 * Simulate a rmfree(), but with the option to
	 * call with size 0 and addr 0 when we just want
	 * to initialize without freeing.
	 */
	ep->m_size = size;
	ep->m_addr = addr;
}

/*
 * Allocate 'size' units from the given
 * map. Return the base of the allocated space.
 * In a map, the addresses are increasing and the
 * list is terminated by a 0 size.
 *
 * Algorithm is first-fit.
 *
 * This routine knows about the interleaving of the swapmap
 * and handles that.
 */
rmalloc(mp, size)
	register struct map *mp;
{
	register struct mapent *ep = (struct mapent *)(mp+1);
	register int addr;
	register struct mapent *bp;
	swblk_t first, rest;

	if (size <= 0 || mp == swapmap && size > DMMAX)
		panic("rmalloc");
	/*
	 * Search for a piece of the resource map which has enough
	 * free space to accomodate the request.
	 */
	for (bp = ep; bp->m_size; bp++) {
		if (bp->m_size >= size) {
			/*
			 * If allocating from swapmap,
			 * then have to respect interleaving
			 * boundaries.
			 */
			if (mp == swapmap &&
			    (first = DMMAX - bp->m_addr%DMMAX) < bp->m_size) {
				if (bp->m_size - first < size)
					continue;
				addr = bp->m_addr + first;
				rest = bp->m_size - first - size;
				bp->m_size = first;
				if (rest)
					rmfree(swapmap, rest, addr+size);
				return (addr);
			}
			/*
			 * Allocate from the map.
			 * If there is no space left of the piece
			 * we allocated from, move the rest of
			 * the pieces to the left.
			 */
			addr = bp->m_addr;
			bp->m_addr += size;
			if ((bp->m_size -= size) == 0) {
				do {
					bp++;
					(bp-1)->m_addr = bp->m_addr;
				} while ((bp-1)->m_size = bp->m_size);
			}
			if (mp == swapmap && addr % CLSIZE)
				panic("rmalloc swapmap");
			return (addr);
		}
	}
	return (0);
}

/*
 * Free the previously allocated space at addr
 * of size units into the specified map.
 * Sort addr into map and combine on
 * one or both ends if possible.
 */
rmfree(mp, size, addr)
	struct map *mp;
	register int size, addr;
{
	struct mapent *firstbp;
	register struct mapent *bp;
	register int t;

	/*
	 * Both address and size must be
	 * positive, or the protocol has broken down.
	 */
	if (addr <= 0 || size <= 0)
		goto badrmfree;
	/*
	 * Locate the piece of the map which starts after the
	 * returned space (or the end of the map).
	 */
	firstbp = bp = (struct mapent *)(mp + 1);
	for (; bp->m_addr <= addr && bp->m_size != 0; bp++)
		continue;
	/*
	 * If the piece on the left abuts us,
	 * then we should combine with it.
	 */
	if (bp > firstbp && (bp-1)->m_addr+(bp-1)->m_size >= addr) {
		/*
		 * Check no overlap (internal error).
		 */
		if ((bp-1)->m_addr+(bp-1)->m_size > addr)
			goto badrmfree;
		/*
		 * Add into piece on the left by increasing its size.
		 */
		(bp-1)->m_size += size;
		/*
		 * If the combined piece abuts the piece on
		 * the right now, compress it in also,
		 * by shifting the remaining pieces of the map over.
		 */
		if (bp->m_addr && addr+size >= bp->m_addr) {
			if (addr+size > bp->m_addr)
				goto badrmfree;
			(bp-1)->m_size += bp->m_size;
			while (bp->m_size) {
				bp++;
				(bp-1)->m_addr = bp->m_addr;
				(bp-1)->m_size = bp->m_size;
			}
		}
		goto done;
	}
	/*
	 * Don't abut on the left, check for abutting on
	 * the right.
	 */
	if (addr+size >= bp->m_addr && bp->m_size) {
		if (addr+size > bp->m_addr)
			goto badrmfree;
		bp->m_addr -= size;
		bp->m_size += size;
		goto done;
	}
	/*
	 * Don't abut at all.  Make a new entry
	 * and check for map overflow.
	 */
	do {
		t = bp->m_addr;
		bp->m_addr = addr;
		addr = t;
		t = bp->m_size;
		bp->m_size = size;
		bp++;
	} while (size = t);
	/*
	 * Segment at bp is to be the delimiter;
	 * If there is not room for it 
	 * then the table is too full
	 * and we must discard something.
	 */
	if (bp+1 > mp->m_limit) {
		/*
		 * Back bp up to last available segment.
		 * which contains a segment already and must
		 * be made into the delimiter.
		 * Discard second to last entry,
		 * since it is presumably smaller than the last
		 * and move the last entry back one.
		 */
		bp--;
		printf("%s: rmap ovflo, lost [%d,%d)\n", mp->m_name,
		    (bp-1)->m_addr, (bp-1)->m_addr+(bp-1)->m_size);
		bp[-1] = bp[0];
		bp[0].m_size = bp[0].m_addr = 0;
	}
done:
	/*
	 * THIS IS RIDICULOUS... IT DOESN'T BELONG HERE!
	 */
	if ((mp == kernelmap) && kmapwnt) {
		kmapwnt = 0;
		wakeup((caddr_t)kernelmap);
	}
	return;
badrmfree:
	panic("bad rmfree");
}

/*
 * Allocate 'size' units from the given map, starting at address 'addr'.
 * Return 'addr' if successful, 0 if not.
 * This may cause the creation or destruction of a resource map segment.
 *
 * This routine will return failure status if there is not enough room
 * for a required additional map segment.
 *
 * An attempt to use this on 'swapmap' will result in
 * a failure return.  This is due mainly to laziness and could be fixed
 * to do the right thing, although it probably will never be used.
 */
rmget(mp, size, addr)
	register struct map *mp;
{
	register struct mapent *ep = (struct mapent *)(mp+1);
	register struct mapent *bp, *bp2;

	if (size <= 0)
		panic("rmget");
	if (mp == swapmap)
		return (0);
	/*
	 * Look for a map segment containing the requested address.
	 * If none found, return failure.
	 */
	for (bp = ep; bp->m_size; bp++)
		if (bp->m_addr <= addr && bp->m_addr + bp->m_size > addr)
			break;
	if (bp->m_size == 0)
		return (0);

	/*
	 * If segment is too small, return failure.
	 * If big enough, allocate the block, compressing or expanding
	 * the map as necessary.
	 */
	if (bp->m_addr + bp->m_size < addr + size)
		return (0);
	if (bp->m_addr == addr)
		if (bp->m_addr + bp->m_size == addr + size) {
			/*
			 * Allocate entire segment and compress map
			 */
			bp2 = bp;
			while (bp2->m_size) {
				bp2++;
				(bp2-1)->m_addr = bp2->m_addr;
				(bp2-1)->m_size = bp2->m_size;
			}
		} else {
			/*
			 * Allocate first part of segment
			 */
			bp->m_addr += size;
			bp->m_size -= size;
		}
	else
		if (bp->m_addr + bp->m_size == addr + size) {
			/*
			 * Allocate last part of segment
			 */
			bp->m_size -= size;
		} else {
			/*
			 * Allocate from middle of segment, but only
			 * if table can be expanded.
			 */
			for (bp2=bp; bp2->m_size; bp2++)
				;
			if (bp2 == mp->m_limit)
				return (0);
			while (bp2 > bp) {
				(bp2+1)->m_addr = bp2->m_addr;
				(bp2+1)->m_size = bp2->m_size;
				bp2--;
			}
			(bp+1)->m_addr = addr + size;
			(bp+1)->m_size =
			    bp->m_addr + bp->m_size - (addr + size);
			bp->m_size = addr - bp->m_addr;
		}
	return (addr);
}
Commit	Line	Data
b9fda884	1	/* subr_rmap.c.sav 4.6 82/10/10 */
2694e78a BJ	2
	3	#include "../h/param.h"
	4	#include "../h/systm.h"
	5	#include "../h/map.h"
	6	#include "../h/dir.h"
	7	#include "../h/user.h"
	8	#include "../h/proc.h"
2694e78a BJ	9	#include "../h/text.h"
2694e78a BJ	10
b725a0ca BJ	11	/*
	12	* Resource map handling routines.
	13	*
	14	* A resource map is an array of structures each
	15	* of which describes a segment of the address space of an available
	16	* resource. The segments are described by their base address and
	17	* length, and sorted in address order. Each resource map has a fixed
	18	* maximum number of segments allowed. Resources are allocated
	19	* by taking part or all of one of the segments of the map.
	20	*
	21	* Returning of resources will require another segment if
	22	* the returned resources are not adjacent in the address
	23	* space to an existing segment. If the return of a segment
	24	* would require a slot which is not available, then one of
	25	* the resource map segments is discarded after a warning is printed.
	26	* Returning of resources may also cause the map to collapse
	27	* by coalescing two existing segments and the returned space
	28	* into a single segment. In this case the resource map is
	29	* made smaller by copying together to fill the resultant gap.
	30	*
	31	* N.B.: the current implementation uses a dense array and does
	32	* not admit the value ``0'' as a legal address, since that is used
	33	* as a delimiter.
	34	*/
	35
	36	/*
	37	* Initialize map mp to have (mapsize-2) segments
	38	* and to be called ``name'', which we print if
	39	* the slots become so fragmented that we lose space.
	40	* The map itself is initialized with size elements free
	41	* starting at addr.
	42	*/
	43	rminit(mp, size, addr, name, mapsize)
	44	register struct map *mp;
	45	int size, addr;
	46	char *name;
	47	int mapsize;
	48	{
	49	register struct mapent ep = (struct mapent )(mp+1);
	50
	51	mp->m_name = name;
	52	/* N.B.: WE ASSUME HERE THAT sizeof (struct map) == sizeof (struct mapent) */
	53	/*
	54	* One of the mapsize slots is taken by the map structure,
	55	* segments has size 0 and addr 0, and acts as a delimiter.
	56	* We insure that we never use segments past the end of
	57	* the array which is given by mp->m_limit.
	58	* Instead, when excess segments occur we discard some resources.
	59	*/
	60	mp->m_limit = (struct mapent *)&mp[mapsize];
	61	/*
	62	* Simulate a rmfree(), but with the option to
	63	* call with size 0 and addr 0 when we just want
	64	* to initialize without freeing.
	65	*/
	66	ep->m_size = size;
	67	ep->m_addr = addr;
	68	}
	69
2694e78a BJ	70	/*
2694e78a BJ	71	* Allocate 'size' units from the given
b725a0ca	72	* map. Return the base of the allocated space.
2694e78a BJ	73	* In a map, the addresses are increasing and the
2694e78a BJ	74	* list is terminated by a 0 size.
b725a0ca	75	*
2694e78a	76	* Algorithm is first-fit.
b725a0ca BJ	77	*
	78	* This routine knows about the interleaving of the swapmap
	79	* and handles that.
2694e78a	80	*/
b725a0ca BJ	81	rmalloc(mp, size)
b725a0ca BJ	82	register struct map *mp;
2694e78a	83	{
b725a0ca BJ	84	register struct mapent ep = (struct mapent )(mp+1);
	85	register int addr;
	86	register struct mapent *bp;
41888f16	87	swblk_t first, rest;
2694e78a	88
41888f16	89	if (size <= 0 \|\| mp == swapmap && size > DMMAX)
b725a0ca BJ	90	panic("rmalloc");
	91	/*
	92	* Search for a piece of the resource map which has enough
	93	* free space to accomodate the request.
	94	*/
	95	for (bp = ep; bp->m_size; bp++) {
2694e78a	96	if (bp->m_size >= size) {
b725a0ca BJ	97	/*
	98	* If allocating from swapmap,
	99	* then have to respect interleaving
	100	* boundaries.
	101	*/
41888f16 BJ	102	if (mp == swapmap &&
	103	(first = DMMAX - bp->m_addr%DMMAX) < bp->m_size) {
	104	if (bp->m_size - first < size)
	105	continue;
b725a0ca	106	addr = bp->m_addr + first;
41888f16 BJ	107	rest = bp->m_size - first - size;
	108	bp->m_size = first;
	109	if (rest)
b725a0ca BJ	110	rmfree(swapmap, rest, addr+size);
b725a0ca BJ	111	return (addr);
41888f16	112	}
b725a0ca BJ	113	/*
	114	* Allocate from the map.
	115	* If there is no space left of the piece
	116	* we allocated from, move the rest of
	117	* the pieces to the left.
	118	*/
	119	addr = bp->m_addr;
2694e78a BJ	120	bp->m_addr += size;
	121	if ((bp->m_size -= size) == 0) {
	122	do {
	123	bp++;
	124	(bp-1)->m_addr = bp->m_addr;
	125	} while ((bp-1)->m_size = bp->m_size);
	126	}
b725a0ca BJ	127	if (mp == swapmap && addr % CLSIZE)
	128	panic("rmalloc swapmap");
	129	return (addr);
2694e78a BJ	130	}
2694e78a BJ	131	}
b725a0ca	132	return (0);
2694e78a BJ	133	}
	134
	135	/*
b725a0ca	136	* Free the previously allocated space at addr
2694e78a	137	* of size units into the specified map.
b725a0ca	138	* Sort addr into map and combine on
2694e78a BJ	139	* one or both ends if possible.
2694e78a BJ	140	*/
b725a0ca BJ	141	rmfree(mp, size, addr)
	142	struct map *mp;
	143	register int size, addr;
2694e78a	144	{
b725a0ca BJ	145	struct mapent *firstbp;
b725a0ca BJ	146	register struct mapent *bp;
2694e78a BJ	147	register int t;
2694e78a BJ	148
b725a0ca BJ	149	/*
	150	* Both address and size must be
	151	* positive, or the protocol has broken down.
	152	*/
	153	if (addr <= 0 \|\| size <= 0)
	154	goto badrmfree;
	155	/*
	156	* Locate the piece of the map which starts after the
	157	* returned space (or the end of the map).
	158	*/
	159	firstbp = bp = (struct mapent *)(mp + 1);
	160	for (; bp->m_addr <= addr && bp->m_size != 0; bp++)
2694e78a	161	continue;
b725a0ca BJ	162	/*
	163	* If the piece on the left abuts us,
	164	* then we should combine with it.
	165	*/
	166	if (bp > firstbp && (bp-1)->m_addr+(bp-1)->m_size >= addr) {
	167	/*
	168	* Check no overlap (internal error).
	169	*/
	170	if ((bp-1)->m_addr+(bp-1)->m_size > addr)
	171	goto badrmfree;
	172	/*
	173	* Add into piece on the left by increasing its size.
	174	*/
2694e78a	175	(bp-1)->m_size += size;
b725a0ca BJ	176	/*
	177	* If the combined piece abuts the piece on
	178	* the right now, compress it in also,
	179	* by shifting the remaining pieces of the map over.
	180	*/
	181	if (bp->m_addr && addr+size >= bp->m_addr) {
	182	if (addr+size > bp->m_addr)
	183	goto badrmfree;
2694e78a BJ	184	(bp-1)->m_size += bp->m_size;
	185	while (bp->m_size) {
	186	bp++;
	187	(bp-1)->m_addr = bp->m_addr;
	188	(bp-1)->m_size = bp->m_size;
	189	}
	190	}
b725a0ca BJ	191	goto done;
	192	}
	193	/*
	194	* Don't abut on the left, check for abutting on
	195	* the right.
	196	*/
	197	if (addr+size >= bp->m_addr && bp->m_size) {
	198	if (addr+size > bp->m_addr)
	199	goto badrmfree;
	200	bp->m_addr -= size;
	201	bp->m_size += size;
	202	goto done;
	203	}
	204	/*
	205	* Don't abut at all. Make a new entry
	206	* and check for map overflow.
	207	*/
	208	do {
	209	t = bp->m_addr;
	210	bp->m_addr = addr;
	211	addr = t;
	212	t = bp->m_size;
	213	bp->m_size = size;
	214	bp++;
	215	} while (size = t);
	216	/*
	217	* Segment at bp is to be the delimiter;
	218	* If there is not room for it
	219	* then the table is too full
	220	* and we must discard something.
	221	*/
	222	if (bp+1 > mp->m_limit) {
	223	/*
	224	* Back bp up to last available segment.
	225	* which contains a segment already and must
	226	* be made into the delimiter.
	227	* Discard second to last entry,
	228	* since it is presumably smaller than the last
	229	* and move the last entry back one.
	230	*/
	231	bp--;
f4c13170	232	printf("%s: rmap ovflo, lost [%d,%d)\n", mp->m_name,
b725a0ca BJ	233	(bp-1)->m_addr, (bp-1)->m_addr+(bp-1)->m_size);
	234	bp[-1] = bp[0];
	235	bp[0].m_size = bp[0].m_addr = 0;
2694e78a	236	}
b725a0ca BJ	237	done:
	238	/*
	239	* THIS IS RIDICULOUS... IT DOESN'T BELONG HERE!
	240	*/
2694e78a BJ	241	if ((mp == kernelmap) && kmapwnt) {
	242	kmapwnt = 0;
	243	wakeup((caddr_t)kernelmap);
	244	}
b725a0ca BJ	245	return;
	246	badrmfree:
	247	panic("bad rmfree");
2694e78a	248	}
1c1f6ecf BF	249
	250	/*
	251	* Allocate 'size' units from the given map, starting at address 'addr'.
	252	* Return 'addr' if successful, 0 if not.
	253	* This may cause the creation or destruction of a resource map segment.
	254	*
	255	* This routine will return failure status if there is not enough room
	256	* for a required additional map segment.
	257	*
	258	* An attempt to use this on 'swapmap' will result in
	259	* a failure return. This is due mainly to laziness and could be fixed
	260	* to do the right thing, although it probably will never be used.
	261	*/
	262	rmget(mp, size, addr)
	263	register struct map *mp;
	264	{
	265	register struct mapent ep = (struct mapent )(mp+1);
	266	register struct mapent bp, bp2;
	267
	268	if (size <= 0)
	269	panic("rmget");
	270	if (mp == swapmap)
	271	return (0);
	272	/*
	273	* Look for a map segment containing the requested address.
	274	* If none found, return failure.
	275	*/
	276	for (bp = ep; bp->m_size; bp++)
	277	if (bp->m_addr <= addr && bp->m_addr + bp->m_size > addr)
	278	break;
	279	if (bp->m_size == 0)
	280	return (0);
	281
	282	/*
	283	* If segment is too small, return failure.
	284	* If big enough, allocate the block, compressing or expanding
	285	* the map as necessary.
	286	*/
	287	if (bp->m_addr + bp->m_size < addr + size)
	288	return (0);
	289	if (bp->m_addr == addr)
	290	if (bp->m_addr + bp->m_size == addr + size) {
	291	/*
	292	* Allocate entire segment and compress map
	293	*/
	294	bp2 = bp;
	295	while (bp2->m_size) {
	296	bp2++;
	297	(bp2-1)->m_addr = bp2->m_addr;
	298	(bp2-1)->m_size = bp2->m_size;
	299	}
	300	} else {
	301	/*
	302	* Allocate first part of segment
	303	*/
	304	bp->m_addr += size;
	305	bp->m_size -= size;
	306	}
	307	else
	308	if (bp->m_addr + bp->m_size == addr + size) {
	309	/*
	310	* Allocate last part of segment
	311	*/
	312	bp->m_size -= size;
313	} else {
314	/*
315	* Allocate from middle of segment, but only
316	* if table can be expanded.
317	*/
318	for (bp2=bp; bp2->m_size; bp2++)
319	;
320	if (bp2 == mp->m_limit)
321	return (0);
322	while (bp2 > bp) {
323	(bp2+1)->m_addr = bp2->m_addr;
324	(bp2+1)->m_size = bp2->m_size;
325	bp2--;
326	}
327	(bp+1)->m_addr = addr + size;
328	(bp+1)->m_size =
329	bp->m_addr + bp->m_size - (addr + size);
330	bp->m_size = addr - bp->m_addr;
331	}
332	return (addr);
333	}