ctl_mem_pool.c revision 259065 
1/*-
2 * Copyright (c) 2003, 2004 Silicon Graphics International Corp.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions, and the following disclaimer,
10 *    without modification.
11 * 2. Redistributions in binary form must reproduce at minimum a disclaimer
12 *    substantially similar to the "NO WARRANTY" disclaimer below
13 *    ("Disclaimer") and any redistribution must be conditioned upon
14 *    including a substantially similar Disclaimer requirement for further
15 *    binary redistribution.
16 *
17 * NO WARRANTY
18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
22 * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
26 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
27 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
28 * POSSIBILITY OF SUCH DAMAGES.
29 *
30 * $Id: //depot/users/kenm/FreeBSD-test2/sys/cam/ctl/ctl_mem_pool.c#1 $
31 */
32/*
33 * CAM Target Layer memory pool code.
34 *
35 * Author: Ken Merry <ken@FreeBSD.org>
36 */
37
38#include <sys/cdefs.h>
39__FBSDID("$FreeBSD: releng/10.0/sys/cam/ctl/ctl_mem_pool.c 229997 2012-01-12 00:34:33Z ken $");
40
41#include <sys/param.h>
42#include <sys/systm.h>
43#include <sys/kernel.h>
44#include <sys/types.h>
45#include <sys/malloc.h>
46#include <sys/lock.h>
47#include <sys/mutex.h>
48#include <sys/condvar.h>
49#include <sys/queue.h>
50
51#include <cam/ctl/ctl_mem_pool.h>
52
53MALLOC_DEFINE(M_CTL_POOL, "ctlpool", "CTL memory pool");
54
55int
56ctl_init_mem_pool(struct ctl_mem_pool *pool, int chunk_size,
57		  ctl_mem_pool_flags flags, int grow_inc,
58		  int initial_pool_size)
59{
60	pool->flags = flags;
61	pool->chunk_size = chunk_size;
62	pool->grow_inc = grow_inc;
63	mtx_init(&pool->lock, "Pool mutex", NULL, MTX_DEF);
64	STAILQ_INIT(&pool->free_mem_list);
65	cv_init(&pool->wait_mem, "CTL mem pool");
66
67	if (ctl_grow_mem_pool(pool, initial_pool_size, /*can_wait*/ 1) !=
68	    initial_pool_size)
69		return (1);
70	else
71		return (0);
72}
73
74struct ctl_mem_element *
75ctl_alloc_mem_element(struct ctl_mem_pool *pool, int can_wait)
76{
77	struct ctl_mem_element *mem;
78
79	for (;;) {
80		mtx_lock(&pool->lock);
81
82		mem = STAILQ_FIRST(&pool->free_mem_list);
83		if (mem != NULL) {
84			STAILQ_REMOVE(&pool->free_mem_list, mem,
85				      ctl_mem_element, links);
86			mem->flags = CTL_MEM_ELEMENT_PREALLOC;
87		}
88		mtx_unlock(&pool->lock);
89
90		if (mem != NULL)
91			return (mem);
92
93		/*
94		 * Grow the pool permanantly by the requested increment
95		 * instead of temporarily.  This has the effect that
96		 * whatever the high water mark of transactions is for
97		 * this pool, we'll keep that much memory around.
98		 */
99		if (pool->flags & CTL_MEM_POOL_PERM_GROW) {
100			if (ctl_grow_mem_pool(pool, pool->grow_inc,
101					      can_wait) != 0)
102				continue;
103		}
104		mem = (struct ctl_mem_element *)malloc(sizeof(*mem),
105			M_CTL_POOL, can_wait ? M_WAITOK : M_NOWAIT);
106
107		if (mem != NULL) {
108			mem->flags = CTL_MEM_ELEMENT_NONE;
109			mem->pool = pool;
110
111			mem->bytes = malloc(pool->chunk_size, M_CTL_POOL,
112				can_wait ?  M_WAITOK : M_NOWAIT);
113			if (mem->bytes == NULL) {
114				free(mem, M_CTL_POOL);
115				mem = NULL;
116			} else {
117				return (mem);
118			}
119		}
120
121		if (can_wait == 0)
122			return (NULL);
123
124		cv_wait_unlock(&pool->wait_mem, &pool->lock);
125	}
126}
127
128void
129ctl_free_mem_element(struct ctl_mem_element *mem)
130{
131	struct ctl_mem_pool *pool;
132
133	pool = mem->pool;
134
135	if (mem->flags & CTL_MEM_ELEMENT_PREALLOC) {
136		mtx_lock(&pool->lock);
137		STAILQ_INSERT_TAIL(&pool->free_mem_list, mem, links);
138		mtx_unlock(&pool->lock);
139		cv_broadcast(&pool->wait_mem);
140	} else
141		free(mem, M_CTL_POOL);
142}
143
144int
145ctl_grow_mem_pool(struct ctl_mem_pool *pool, int count, int can_wait)
146{
147	int i;
148
149	for (i = 0; i < count; i++) {
150		struct ctl_mem_element *mem;
151
152		mem = (struct ctl_mem_element *)malloc(sizeof(*mem),
153			M_CTL_POOL, can_wait ? M_WAITOK : M_NOWAIT);
154
155		if (mem == NULL)
156			break;
157
158		mem->bytes = malloc(pool->chunk_size, M_CTL_POOL, can_wait ?
159				     M_WAITOK : M_NOWAIT);
160		if (mem->bytes == NULL) {
161			free(mem, M_CTL_POOL);
162			break;
163		}
164		mem->flags = CTL_MEM_ELEMENT_PREALLOC;
165		mem->pool = pool;
166		mtx_lock(&pool->lock);
167		STAILQ_INSERT_TAIL(&pool->free_mem_list, mem, links);
168		mtx_unlock(&pool->lock);
169	}
170
171	return (i);
172}
173
174int
175ctl_shrink_mem_pool(struct ctl_mem_pool *pool)
176{
177	struct ctl_mem_element *mem, *mem_next;
178
179	mtx_lock(&pool->lock);
180	for (mem = STAILQ_FIRST(&pool->free_mem_list); mem != NULL;
181	     mem = mem_next) {
182		mem_next = STAILQ_NEXT(mem, links);
183
184		STAILQ_REMOVE(&pool->free_mem_list, mem, ctl_mem_element,
185			      links);
186		free(mem->bytes, M_CTL_POOL);
187		free(mem, M_CTL_POOL);
188	}
189	mtx_unlock(&pool->lock);
190
191	return (0);
192}
193