1 /* $NetBSD: memlock.c,v 1.1.1.2 2009/12/02 00:26:25 haad Exp $ */
4 * Copyright (C) 2003-2004 Sistina Software, Inc. All rights reserved.
5 * Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved.
7 * This file is part of LVM2.
9 * This copyrighted material is made available to anyone wishing to use,
10 * modify, copy, or redistribute it subject to the terms and conditions
11 * of the GNU Lesser General Public License v.2.1.
13 * You should have received a copy of the GNU Lesser General Public License
14 * along with this program; if not, write to the Free Software Foundation,
15 * Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
22 #include "toolcontext.h"
29 #include <sys/resource.h>
31 #ifndef DEVMAPPER_SUPPORT
33 void memlock_inc(void)
37 void memlock_dec(void)
45 void memlock_init(struct cmd_context *cmd)
50 #else /* DEVMAPPER_SUPPORT */
52 static size_t _size_stack;
53 static size_t _size_malloc_tmp;
54 static size_t _size_malloc = 2000000;
56 static void *_malloc_mem = NULL;
57 static int _memlock_count = 0;
58 static int _memlock_count_daemon = 0;
60 static int _default_priority;
62 static void _touch_memory(void *mem, size_t size)
64 size_t pagesize = lvm_getpagesize();
66 void *end = mem + size - sizeof(long);
74 static void _allocate_memory(void)
76 void *stack_mem, *temp_malloc_mem;
78 if ((stack_mem = alloca(_size_stack)))
79 _touch_memory(stack_mem, _size_stack);
81 if ((temp_malloc_mem = malloc(_size_malloc_tmp)))
82 _touch_memory(temp_malloc_mem, _size_malloc_tmp);
84 if ((_malloc_mem = malloc(_size_malloc)))
85 _touch_memory(_malloc_mem, _size_malloc);
87 free(temp_malloc_mem);
90 static void _release_memory(void)
95 #undef MCL_CURRENT /* XXX: please implement m{,un}lockall */
97 /* Stop memory getting swapped out */
98 static void _lock_mem(void)
101 if (mlockall(MCL_CURRENT | MCL_FUTURE))
102 log_sys_error("mlockall", "");
104 log_very_verbose("Locking memory");
109 if (((_priority = getpriority(PRIO_PROCESS, 0)) == -1) && errno)
110 log_sys_error("getpriority", "");
112 if (setpriority(PRIO_PROCESS, 0, _default_priority))
113 log_error("setpriority %d failed: %s",
114 _default_priority, strerror(errno));
117 static void _unlock_mem(void)
121 log_sys_error("munlockall", "");
123 log_very_verbose("Unlocking memory");
126 if (setpriority(PRIO_PROCESS, 0, _priority))
127 log_error("setpriority %u failed: %s", _priority,
131 static void _lock_mem_if_needed(void) {
132 if ((_memlock_count + _memlock_count_daemon) == 1)
136 static void _unlock_mem_if_possible(void) {
137 if ((_memlock_count + _memlock_count_daemon) == 0)
141 void memlock_inc(void)
144 _lock_mem_if_needed();
145 log_debug("memlock_count inc to %d", _memlock_count);
148 void memlock_dec(void)
151 log_error("Internal error: _memlock_count has dropped below 0.");
153 _unlock_mem_if_possible();
154 log_debug("memlock_count dec to %d", _memlock_count);
158 * The memlock_*_daemon functions will force the mlockall() call that we need
159 * to stay in memory, but they will have no effect on device scans (unlike
160 * normal memlock_inc and memlock_dec). Memory is kept locked as long as either
161 * of memlock or memlock_daemon is in effect.
164 void memlock_inc_daemon(void)
166 ++_memlock_count_daemon;
167 _lock_mem_if_needed();
168 log_debug("memlock_count_daemon inc to %d", _memlock_count_daemon);
171 void memlock_dec_daemon(void)
173 if (!_memlock_count_daemon)
174 log_error("Internal error: _memlock_count_daemon has dropped below 0.");
175 --_memlock_count_daemon;
176 _unlock_mem_if_possible();
177 log_debug("memlock_count_daemon dec to %d", _memlock_count_daemon);
181 * This disregards the daemon (dmeventd) locks, since we use memlock() to check
182 * whether it is safe to run a device scan, which would normally coincide with
183 * !memlock() -- but the daemon global memory lock breaks this assumption, so
184 * we do not take those into account here.
188 return _memlock_count;
191 void memlock_init(struct cmd_context *cmd)
193 _size_stack = find_config_tree_int(cmd,
194 "activation/reserved_stack",
195 DEFAULT_RESERVED_STACK) * 1024;
196 _size_malloc_tmp = find_config_tree_int(cmd,
197 "activation/reserved_memory",
198 DEFAULT_RESERVED_MEMORY) * 1024;
199 _default_priority = find_config_tree_int(cmd,
200 "activation/process_priority",
201 DEFAULT_PROCESS_PRIORITY);