path: root/kern/kalloc.c

/*
 * Mach Operating System
 * Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University.
 * Copyright (c) 1993,1994 The University of Utah and
 * the Computer Systems Laboratory (CSL).
 * All rights reserved.
 *
 * Permission to use, copy, modify and distribute this software and its
 * documentation is hereby granted, provided that both the copyright
 * notice and this permission notice appear in all copies of the
 * software, derivative works or modified versions, and any portions
 * thereof, and that both notices appear in supporting documentation.
 *
 * CARNEGIE MELLON, THE UNIVERSITY OF UTAH AND CSL ALLOW FREE USE OF
 * THIS SOFTWARE IN ITS "AS IS" CONDITION, AND DISCLAIM ANY LIABILITY
 * OF ANY KIND FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF
 * THIS SOFTWARE.
 *
 * Carnegie Mellon requests users of this software to return to
 *
 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
 *  School of Computer Science
 *  Carnegie Mellon University
 *  Pittsburgh PA 15213-3890
 *
 * any improvements or extensions that they make and grant Carnegie Mellon
 * the rights to redistribute these changes.
 */
/*
 *	File:	kern/kalloc.c
 *	Author:	Avadis Tevanian, Jr.
 *	Date:	1985
 *
 *	General kernel memory allocator.  This allocator is designed
 *	to be used by the kernel to manage dynamic memory fast.
 */

#include <mach/machine/vm_types.h>
#include <mach/vm_param.h>

#include <kern/debug.h>  /* for panic() */
#include <kern/zalloc.h>
#include <kern/kalloc.h>
#include <vm/vm_kern.h>
#include <vm/vm_object.h>
#include <vm/vm_map.h>



vm_map_t kalloc_map;
vm_size_t kalloc_map_size = 8 * 1024 * 1024;
vm_size_t kalloc_max;

/*
 *	All allocations of size less than kalloc_max are rounded to the
 *	next highest power of 2.  This allocator is built on top of
 *	the zone allocator.  A zone is created for each potential size
 *	that we are willing to get in small blocks.
 *
 *	We assume that kalloc_max is not greater than 64K;
 *	thus 16 is a safe array size for k_zone and k_zone_name.
 */

int first_k_zone = -1;
struct zone *k_zone[16];
static char *k_zone_name[16] = {
	"kalloc.1",		"kalloc.2",
	"kalloc.4",		"kalloc.8",
	"kalloc.16",		"kalloc.32",
	"kalloc.64",		"kalloc.128",
	"kalloc.256",		"kalloc.512",
	"kalloc.1024",		"kalloc.2048",
	"kalloc.4096",		"kalloc.8192",
	"kalloc.16384",		"kalloc.32768"
};

/*
 *  Max number of elements per zone.  zinit rounds things up correctly
 *  Doing things this way permits each zone to have a different maximum size
 *  based on need, rather than just guessing; it also
 *  means its patchable in case you're wrong!
 */
unsigned long k_zone_max[16] = {
      1024,		/*      1 Byte  */
      1024,		/*      2 Byte  */
      1024,		/*      4 Byte  */
      1024,		/*      8 Byte  */
      1024,		/*     16 Byte  */
      4096,		/*     32 Byte  */
      4096,		/*     64 Byte  */
      4096,		/*    128 Byte  */
      4096,		/*    256 Byte  */
      1024,		/*    512 Byte  */
      1024,		/*   1024 Byte  */
      1024,		/*   2048 Byte  */
      1024,		/*   4096 Byte  */
      4096,		/*   8192 Byte  */
      64,		/*  16384 Byte  */
      64,		/*  32768 Byte  */
};

/*
 *	Initialize the memory allocator.  This should be called only
 *	once on a system wide basis (i.e. first processor to get here
 *	does the initialization).
 *
 *	This initializes all of the zones.
 */

#ifndef NDEBUG
static int kalloc_init_called;
#endif

void kalloc_init()
{
	vm_offset_t min, max;
	vm_size_t size;
	register int i;

	assert (! kalloc_init_called);

	kalloc_map = kmem_suballoc(kernel_map, &min, &max,
				   kalloc_map_size, FALSE);

	/*
	 *	Ensure that zones up to size 8192 bytes exist.
	 *	This is desirable because messages are allocated
	 *	with kalloc, and messages up through size 8192 are common.
	 */

	if (PAGE_SIZE < 16*1024)
		kalloc_max = 16*1024;
	else
		kalloc_max = PAGE_SIZE;

	/*
	 *	Allocate a zone for each size we are going to handle.
	 *	We specify non-paged memory.
	 */
	for (i = 0, size = 1; size < kalloc_max; i++, size <<= 1) {
		if (size < MINSIZE) {
			k_zone[i] = 0;
			continue;
		}
		if (size == MINSIZE) {
			first_k_zone = i;
		}
		k_zone[i] = zinit(size, k_zone_max[i] * size, size,
				  size >= PAGE_SIZE ? ZONE_COLLECTABLE : 0,
				  k_zone_name[i]);
	}

#ifndef NDEBUG
	kalloc_init_called = 1;
#endif
}

vm_offset_t kalloc(size)
	vm_size_t size;
{
	register int zindex;
	register vm_size_t allocsize;
	vm_offset_t addr;

	/* compute the size of the block that we will actually allocate */

	assert (kalloc_init_called);

	allocsize = size;
	if (size < kalloc_max) {
		allocsize = MINSIZE;
		zindex = first_k_zone;
		while (allocsize < size) {
			allocsize <<= 1;
			zindex++;
		}
	}

	/*
	 * If our size is still small enough, check the queue for that size
	 * and allocate.
	 */

	if (allocsize < kalloc_max) {
		addr = zalloc(k_zone[zindex]);
	} else {
		if (kmem_alloc_wired(kalloc_map, &addr, allocsize)
							!= KERN_SUCCESS)
			addr = 0;
	}
	return(addr);
}

vm_offset_t kget(size)
	vm_size_t size;
{
	register int zindex;
	register vm_size_t allocsize;
	vm_offset_t addr;

	assert (kalloc_init_called);

	/* compute the size of the block that we will actually allocate */

	allocsize = size;
	if (size < kalloc_max) {
		allocsize = MINSIZE;
		zindex = first_k_zone;
		while (allocsize < size) {
			allocsize <<= 1;
			zindex++;
		}
	}

	/*
	 * If our size is still small enough, check the queue for that size
	 * and allocate.
	 */

	if (allocsize < kalloc_max) {
		addr = zget(k_zone[zindex]);
	} else {
		/* This will never work, so we might as well panic */
		panic("kget");
	}
	return(addr);
}

void
kfree(data, size)
	vm_offset_t data;
	vm_size_t size;
{
	register int zindex;
	register vm_size_t freesize;

	assert (kalloc_init_called);

	freesize = size;
	if (size < kalloc_max) {
		freesize = MINSIZE;
		zindex = first_k_zone;
		while (freesize < size) {
			freesize <<= 1;
			zindex++;
		}
	}

	if (freesize < kalloc_max) {
		zfree(k_zone[zindex], data);
	} else {
		kmem_free(kalloc_map, data, freesize);
	}
}