[mirror_zfs-debian.git] / zfs / lib / libumem / vmem_mmap.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#pragma ident	"%Z%%M%	%I%	%E% SMI"

#include <unistd.h>
#include <errno.h>
#include <sys/mman.h>
#include <sys/sysmacros.h>
#include "vmem_base.h"

#define	ALLOC_PROT	PROT_READ | PROT_WRITE | PROT_EXEC
#define	FREE_PROT	PROT_NONE

#define	ALLOC_FLAGS	MAP_PRIVATE | MAP_ANON
#define	FREE_FLAGS	MAP_PRIVATE | MAP_ANON | MAP_NORESERVE

#define	CHUNKSIZE	(64*1024)	/* 64 kilobytes */

static vmem_t *mmap_heap;

static void *
vmem_mmap_alloc(vmem_t *src, size_t size, int vmflags)
{
	void *ret;
	int old_errno = errno;

	ret = vmem_alloc(src, size, vmflags);
	if (ret != NULL &&
	    mmap(ret, size, ALLOC_PROT, ALLOC_FLAGS | MAP_FIXED, -1, 0) ==
	    MAP_FAILED) {
		vmem_free(src, ret, size);
		vmem_reap();

		ASSERT((vmflags & VM_NOSLEEP) == VM_NOSLEEP);
		errno = old_errno;
		return (NULL);
	}

	errno = old_errno;
	return (ret);
}

static void
vmem_mmap_free(vmem_t *src, void *addr, size_t size)
{
	int old_errno = errno;
	(void) mmap(addr, size, FREE_PROT, FREE_FLAGS | MAP_FIXED, -1, 0);
	vmem_free(src, addr, size);
	errno = old_errno;
}

static void *
vmem_mmap_top_alloc(vmem_t *src, size_t size, int vmflags)
{
	void *ret;
	void *buf;
	int old_errno = errno;

	ret = vmem_alloc(src, size, VM_NOSLEEP);

	if (ret) {
		errno = old_errno;
		return (ret);
	}
	/*
	 * Need to grow the heap
	 */
	buf = mmap((void *)CHUNKSIZE, size, FREE_PROT, FREE_FLAGS | MAP_ALIGN,
	    -1, 0);

	if (buf != MAP_FAILED) {
		ret = _vmem_extend_alloc(src, buf, size, size, vmflags);
		if (ret != NULL)
			return (ret);
		else {
			(void) munmap(buf, size);
			errno = old_errno;
			return (NULL);
		}
	} else {
		/*
		 * Growing the heap failed.  The allocation above will
		 * already have called umem_reap().
		 */
		ASSERT((vmflags & VM_NOSLEEP) == VM_NOSLEEP);

		errno = old_errno;
		return (NULL);
	}
}

vmem_t *
vmem_mmap_arena(vmem_alloc_t **a_out, vmem_free_t **f_out)
{
	size_t pagesize = sysconf(_SC_PAGESIZE);

	if (mmap_heap == NULL) {
		mmap_heap = vmem_init("mmap_top", CHUNKSIZE,
		    vmem_mmap_top_alloc, vmem_free,
		    "mmap_heap", NULL, 0, pagesize,
		    vmem_mmap_alloc, vmem_mmap_free);
	}

	if (a_out != NULL)
		*a_out = vmem_mmap_alloc;
	if (f_out != NULL)
		*f_out = vmem_mmap_free;

	return (mmap_heap);
}
Commit	Line	Data
34dc7c2f BB	1	/*
	2	* CDDL HEADER START
	3	*
	4	* The contents of this file are subject to the terms of the
b128c09f BB	5	* Common Development and Distribution License (the "License").
b128c09f BB	6	* You may not use this file except in compliance with the License.
34dc7c2f BB	7	*
	8	* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
	9	* or http://www.opensolaris.org/os/licensing.
	10	* See the License for the specific language governing permissions
	11	* and limitations under the License.
	12	*
	13	* When distributing Covered Code, include this CDDL HEADER in each
	14	* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
	15	* If applicable, add the following below this CDDL HEADER, with the
	16	* fields enclosed by brackets "[]" replaced with your own identifying
	17	* information: Portions Copyright [yyyy] [name of copyright owner]
	18	*
	19	* CDDL HEADER END
	20	*/
b128c09f	21
34dc7c2f	22	/*
b128c09f	23	* Copyright 2008 Sun Microsystems, Inc. All rights reserved.
34dc7c2f BB	24	* Use is subject to license terms.
34dc7c2f BB	25	*/
34dc7c2f	26
b128c09f	27	#pragma ident "%Z%%M% %I% %E% SMI"
34dc7c2f	28
b128c09f	29	#include <unistd.h>
34dc7c2f	30	#include <errno.h>
34dc7c2f	31	#include <sys/mman.h>
34dc7c2f	32	#include <sys/sysmacros.h>
34dc7c2f BB	33	#include "vmem_base.h"
	34
	35	#define ALLOC_PROT PROT_READ \| PROT_WRITE \| PROT_EXEC
	36	#define FREE_PROT PROT_NONE
	37
	38	#define ALLOC_FLAGS MAP_PRIVATE \| MAP_ANON
	39	#define FREE_FLAGS MAP_PRIVATE \| MAP_ANON \| MAP_NORESERVE
	40
34dc7c2f	41	#define CHUNKSIZE (641024) / 64 kilobytes */
34dc7c2f BB	42
	43	static vmem_t *mmap_heap;
	44
	45	static void *
	46	vmem_mmap_alloc(vmem_t *src, size_t size, int vmflags)
	47	{
	48	void *ret;
	49	int old_errno = errno;
	50
	51	ret = vmem_alloc(src, size, vmflags);
b128c09f	52	if (ret != NULL &&
34dc7c2f	53	mmap(ret, size, ALLOC_PROT, ALLOC_FLAGS \| MAP_FIXED, -1, 0) ==
b128c09f	54	MAP_FAILED) {
34dc7c2f BB	55	vmem_free(src, ret, size);
	56	vmem_reap();
	57
	58	ASSERT((vmflags & VM_NOSLEEP) == VM_NOSLEEP);
	59	errno = old_errno;
	60	return (NULL);
	61	}
34dc7c2f BB	62
	63	errno = old_errno;
	64	return (ret);
	65	}
	66
	67	static void
	68	vmem_mmap_free(vmem_t src, void addr, size_t size)
	69	{
	70	int old_errno = errno;
34dc7c2f	71	(void) mmap(addr, size, FREE_PROT, FREE_FLAGS \| MAP_FIXED, -1, 0);
34dc7c2f BB	72	vmem_free(src, addr, size);
	73	errno = old_errno;
	74	}
	75
	76	static void *
	77	vmem_mmap_top_alloc(vmem_t *src, size_t size, int vmflags)
	78	{
	79	void *ret;
	80	void *buf;
	81	int old_errno = errno;
	82
	83	ret = vmem_alloc(src, size, VM_NOSLEEP);
	84
	85	if (ret) {
	86	errno = old_errno;
	87	return (ret);
	88	}
	89	/*
	90	* Need to grow the heap
	91	*/
b128c09f BB	92	buf = mmap((void *)CHUNKSIZE, size, FREE_PROT, FREE_FLAGS \| MAP_ALIGN,
b128c09f BB	93	-1, 0);
34dc7c2f BB	94
	95	if (buf != MAP_FAILED) {
	96	ret = _vmem_extend_alloc(src, buf, size, size, vmflags);
	97	if (ret != NULL)
	98	return (ret);
	99	else {
	100	(void) munmap(buf, size);
	101	errno = old_errno;
	102	return (NULL);
	103	}
	104	} else {
	105	/*
	106	* Growing the heap failed. The allocation above will
	107	* already have called umem_reap().
	108	*/
	109	ASSERT((vmflags & VM_NOSLEEP) == VM_NOSLEEP);
	110
	111	errno = old_errno;
	112	return (NULL);
	113	}
	114	}
	115
	116	vmem_t *
	117	vmem_mmap_arena(vmem_alloc_t a_out, vmem_free_t f_out)
	118	{
b128c09f BB	119	size_t pagesize = sysconf(_SC_PAGESIZE);
b128c09f BB	120
34dc7c2f	121	if (mmap_heap == NULL) {
b128c09f	122	mmap_heap = vmem_init("mmap_top", CHUNKSIZE,
34dc7c2f BB	123	vmem_mmap_top_alloc, vmem_free,
	124	"mmap_heap", NULL, 0, pagesize,
	125	vmem_mmap_alloc, vmem_mmap_free);
	126	}
	127
	128	if (a_out != NULL)
	129	*a_out = vmem_mmap_alloc;
	130	if (f_out != NULL)
	131	*f_out = vmem_mmap_free;
	132
	133	return (mmap_heap);
	134	}