1 /* GIO - GLib Input, Output and Streaming Library
3 * Copyright 2019 Red Hat, Inc
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Lesser General Public
7 * License as published by the Free Software Foundation; either
8 * version 2.1 of the License, or (at your option) any later version.
10 * This library is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * Lesser General Public License for more details.
15 * You should have received a copy of the GNU Lesser General
16 * Public License along with this library; if not, see <http://www.gnu.org/licenses/>.
23 #include "gmemorymonitor.h"
24 #include "ginetaddress.h"
25 #include "ginetsocketaddress.h"
26 #include "ginitable.h"
27 #include "gioenumtypes.h"
28 #include "giomodule-priv.h"
32 * SECTION:gmemorymonitor
33 * @title: GMemoryMonitor
34 * @short_description: Memory usage monitor
37 * #GMemoryMonitor will monitor system memory and suggest to the application
38 * when to free memory so as to leave more room for other applications.
39 * It is implemented on Linux using the [Low Memory Monitor](https://gitlab.freedesktop.org/hadess/low-memory-monitor/)
40 * ([API documentation](https://hadess.pages.freedesktop.org/low-memory-monitor/)).
42 * There is also an implementation for use inside Flatpak sandboxes.
44 * Possible actions to take when the signal is received are:
46 * - Save files that haven't been looked at in a while to disk, ready to be reopened when needed
47 * - Run a garbage collection cycle
48 * - Try and compress fragmented allocations
49 * - Exit on idle if the process has no reason to stay around
51 * See #GMemoryMonitorWarningLevel for details on the various warning levels.
53 * |[<!-- language="C" -->
55 * warning_cb (GMemoryMonitor *m, GMemoryMonitorWarningLevel level)
57 * g_debug ("Warning level: %d", level);
58 * if (warning_level > G_MEMORY_MONITOR_WARNING_LEVEL_LOW)
62 * static GMemoryMonitor *
63 * monitor_low_memory (void)
66 * m = g_memory_monitor_dup_default ();
67 * g_signal_connect (G_OBJECT (m), "low-memory-warning",
68 * G_CALLBACK (warning_cb), NULL);
73 * Don't forget to disconnect the #GMemoryMonitor::low-memory-warning
74 * signal, and unref the #GMemoryMonitor itself when exiting.
82 * #GMemoryMonitor monitors system memory and indicates when
83 * the system is low on memory.
89 * GMemoryMonitorInterface:
90 * @g_iface: The parent interface.
91 * @low_memory_warning: the virtual function pointer for the
92 * #GMemoryMonitor::low-memory-warning signal.
94 * The virtual function table for #GMemoryMonitor.
99 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))
107 static guint signals[LAST_SIGNAL] = { 0 };
110 * g_memory_monitor_dup_default:
112 * Gets a reference to the default #GMemoryMonitor for the system.
114 * Returns: (transfer full): a new reference to the default #GMemoryMonitor
119 g_memory_monitor_dup_default (void)
121 return g_object_ref (_g_io_module_get_default (G_MEMORY_MONITOR_EXTENSION_POINT_NAME,
122 "GIO_USE_MEMORY_MONITOR",
127 g_memory_monitor_default_init (GMemoryMonitorInterface *iface)
130 * GMemoryMonitor::low-memory-warning:
131 * @monitor: a #GMemoryMonitor
132 * @level: the #GMemoryMonitorWarningLevel warning level
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
141 signals[LOW_MEMORY_WARNING] =
142 g_signal_new (I_("low-memory-warning"),
143 G_TYPE_MEMORY_MONITOR,
145 G_STRUCT_OFFSET (GMemoryMonitorInterface, low_memory_warning),
149 G_TYPE_MEMORY_MONITOR_WARNING_LEVEL);