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1 : : /* GIO - GLib Input, Output and Streaming Library 2 : : * 3 : : * Copyright 2019 Red Hat, Inc 4 : : * 5 : : * SPDX-License-Identifier: LGPL-2.1-or-later 6 : : * 7 : : * This library is free software; you can redistribute it and/or 8 : : * modify it under the terms of the GNU Lesser General Public 9 : : * License as published by the Free Software Foundation; either 10 : : * version 2.1 of the License, or (at your option) any later version. 11 : : * 12 : : * This library is distributed in the hope that it will be useful, 13 : : * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 : : * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 15 : : * Lesser General Public License for more details. 16 : : * 17 : : * You should have received a copy of the GNU Lesser General 18 : : * Public License along with this library; if not, see <http://www.gnu.org/licenses/>. 19 : : */ 20 : : 21 : : #include "config.h" 22 : : #include "glib.h" 23 : : #include "glibintl.h" 24 : : 25 : : #include "gmemorymonitor.h" 26 : : #include "ginetaddress.h" 27 : : #include "ginetsocketaddress.h" 28 : : #include "ginitable.h" 29 : : #include "gioenumtypes.h" 30 : : #include "giomodule-priv.h" 31 : : #include "gtask.h" 32 : : 33 : : /** 34 : : * GMemoryMonitor: 35 : : * 36 : : * `GMemoryMonitor` will monitor system memory and suggest to the application 37 : : * when to free memory so as to leave more room for other applications. 38 : : * It is implemented on Linux using the 39 : : * [Low Memory Monitor](https://gitlab.freedesktop.org/hadess/low-memory-monitor/) 40 : : * ([API documentation](https://hadess.pages.freedesktop.org/low-memory-monitor/)). 41 : : * 42 : : * There is also an implementation for use inside Flatpak sandboxes. 43 : : * 44 : : * Possible actions to take when the signal is received are: 45 : : * 46 : : * - Free caches 47 : : * - Save files that haven’t been looked at in a while to disk, ready to be reopened when needed 48 : : * - Run a garbage collection cycle 49 : : * - Try and compress fragmented allocations 50 : : * - Exit on idle if the process has no reason to stay around 51 : : * - Call [`malloc_trim(3)`](man:malloc_trim(3)) to return cached heap pages to 52 : : * the kernel (if supported by your libc) 53 : : * 54 : : * Note that some actions may not always improve system performance, and so 55 : : * should be profiled for your application. `malloc_trim()`, for example, may 56 : : * make future heap allocations slower (due to releasing cached heap pages back 57 : : * to the kernel). 58 : : * 59 : : * See [type@Gio.MemoryMonitorWarningLevel] for details on the various warning 60 : : * levels. 61 : : * 62 : : * ```c 63 : : * static void 64 : : * warning_cb (GMemoryMonitor *m, GMemoryMonitorWarningLevel level) 65 : : * { 66 : : * g_debug ("Warning level: %d", level); 67 : : * if (warning_level > G_MEMORY_MONITOR_WARNING_LEVEL_LOW) 68 : : * drop_caches (); 69 : : * } 70 : : * 71 : : * static GMemoryMonitor * 72 : : * monitor_low_memory (void) 73 : : * { 74 : : * GMemoryMonitor *m; 75 : : * m = g_memory_monitor_dup_default (); 76 : : * g_signal_connect (G_OBJECT (m), "low-memory-warning", 77 : : * G_CALLBACK (warning_cb), NULL); 78 : : * return m; 79 : : * } 80 : : * ``` 81 : : * 82 : : * Don’t forget to disconnect the [signal@Gio.MemoryMonitor::low-memory-warning] 83 : : * signal, and unref the `GMemoryMonitor` itself when exiting. 84 : : * 85 : : * Since: 2.64 86 : : */ 87 : : 88 : : /** 89 : : * GMemoryMonitorInterface: 90 : : * @g_iface: The parent interface. 91 : : * @low_memory_warning: the virtual function pointer for the 92 : : * #GMemoryMonitor::low-memory-warning signal. 93 : : * 94 : : * The virtual function table for #GMemoryMonitor. 95 : : * 96 : : * Since: 2.64 97 : : */ 98 : : 99 [ + + + - : 349 : G_DEFINE_INTERFACE_WITH_CODE (GMemoryMonitor, g_memory_monitor, G_TYPE_OBJECT, + + ] 100 : : g_type_interface_add_prerequisite (g_define_type_id, G_TYPE_INITABLE)) 101 : : 102 : : enum { 103 : : LOW_MEMORY_WARNING, 104 : : LAST_SIGNAL 105 : : }; 106 : : 107 : : static guint signals[LAST_SIGNAL] = { 0 }; 108 : : 109 : : /** 110 : : * g_memory_monitor_dup_default: 111 : : * 112 : : * Gets a reference to the default #GMemoryMonitor for the system. 113 : : * 114 : : * Returns: (not nullable) (transfer full): a new reference to the default #GMemoryMonitor 115 : : * 116 : : * Since: 2.64 117 : : */ 118 : : GMemoryMonitor * 119 : 1 : g_memory_monitor_dup_default (void) 120 : : { 121 : 1 : return g_object_ref (_g_io_module_get_default (G_MEMORY_MONITOR_EXTENSION_POINT_NAME, 122 : : "GIO_USE_MEMORY_MONITOR", 123 : : NULL)); 124 : : } 125 : : 126 : : static void 127 : 2 : g_memory_monitor_default_init (GMemoryMonitorInterface *iface) 128 : : { 129 : : /** 130 : : * GMemoryMonitor::low-memory-warning: 131 : : * @monitor: a #GMemoryMonitor 132 : : * @level: the #GMemoryMonitorWarningLevel warning level 133 : : * 134 : : * Emitted when the system is running low on free memory. The signal 135 : : * handler should then take the appropriate action depending on the 136 : : * warning level. See the #GMemoryMonitorWarningLevel documentation for 137 : : * details. 138 : : * 139 : : * Since: 2.64 140 : : */ 141 : 2 : signals[LOW_MEMORY_WARNING] = 142 : 2 : g_signal_new (I_("low-memory-warning"), 143 : : G_TYPE_MEMORY_MONITOR, 144 : : G_SIGNAL_RUN_LAST, 145 : : G_STRUCT_OFFSET (GMemoryMonitorInterface, low_memory_warning), 146 : : NULL, NULL, 147 : : NULL, 148 : : G_TYPE_NONE, 1, 149 : : G_TYPE_MEMORY_MONITOR_WARNING_LEVEL); 150 : 2 : }