/src/glib/gio/gmemorymonitor.c

Source (jump to first uncovered line)
/* GIO - GLib Input, Output and Streaming Library
 *
 * Copyright 2019 Red Hat, Inc
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General
 * Public License along with this library; if not, see <http://www.gnu.org/licenses/>.
 */

#include "config.h"
#include "glib.h"
#include "glibintl.h"

#include "gmemorymonitor.h"
#include "ginetaddress.h"
#include "ginetsocketaddress.h"
#include "ginitable.h"
#include "gioenumtypes.h"
#include "giomodule-priv.h"
#include "gtask.h"

/**
 * SECTION:gmemorymonitor
 * @title: GMemoryMonitor
 * @short_description: Memory usage monitor
 * @include: gio/gio.h
 *
 * #GMemoryMonitor will monitor system memory and suggest to the application
 * when to free memory so as to leave more room for other applications.
 * It is implemented on Linux using the [Low Memory Monitor](https://gitlab.freedesktop.org/hadess/low-memory-monitor/)
 * ([API documentation](https://hadess.pages.freedesktop.org/low-memory-monitor/)).
 *
 * There is also an implementation for use inside Flatpak sandboxes.
 *
 * Possible actions to take when the signal is received are:
 * - Free caches
 * - Save files that haven't been looked at in a while to disk, ready to be reopened when needed
 * - Run a garbage collection cycle
 * - Try and compress fragmented allocations
 * - Exit on idle if the process has no reason to stay around
 * - Call [`malloc_trim(3)`](man:malloc_trim) to return cached heap pages to
 *   the kernel (if supported by your libc)
 *
 * Note that some actions may not always improve system performance, and so
 * should be profiled for your application. `malloc_trim()`, for example, may
 * make future heap allocations slower (due to releasing cached heap pages back
 * to the kernel).
 *
 * See #GMemoryMonitorWarningLevel for details on the various warning levels.
 *
 * |[<!-- language="C" -->
 * static void
 * warning_cb (GMemoryMonitor *m, GMemoryMonitorWarningLevel level)
 * {
 *   g_debug ("Warning level: %d", level);
 *   if (warning_level > G_MEMORY_MONITOR_WARNING_LEVEL_LOW)
 *     drop_caches ();
 * }
 *
 * static GMemoryMonitor *
 * monitor_low_memory (void)
 * {
 *   GMemoryMonitor *m;
 *   m = g_memory_monitor_dup_default ();
 *   g_signal_connect (G_OBJECT (m), "low-memory-warning",
 *                     G_CALLBACK (warning_cb), NULL);
 *   return m;
 * }
 * ]|
 *
 * Don't forget to disconnect the #GMemoryMonitor::low-memory-warning
 * signal, and unref the #GMemoryMonitor itself when exiting.
 *
 * Since: 2.64
 */

/**
 * GMemoryMonitor:
 *
 * #GMemoryMonitor monitors system memory and indicates when
 * the system is low on memory.
 *
 * Since: 2.64
 */

/**
 * GMemoryMonitorInterface:
 * @g_iface: The parent interface.
 * @low_memory_warning: the virtual function pointer for the
 *  #GMemoryMonitor::low-memory-warning signal.
 *
 * The virtual function table for #GMemoryMonitor.
 *
 * Since: 2.64
 */

G_DEFINE_INTERFACE_WITH_CODE (GMemoryMonitor, g_memory_monitor, G_TYPE_OBJECT,
                              g_type_interface_add_prerequisite (g_define_type_id, G_TYPE_INITABLE))

enum {
  LOW_MEMORY_WARNING,
  LAST_SIGNAL
};

static guint signals[LAST_SIGNAL] = { 0 };

/**
 * g_memory_monitor_dup_default:
 *
 * Gets a reference to the default #GMemoryMonitor for the system.
 *
 * Returns: (not nullable) (transfer full): a new reference to the default #GMemoryMonitor
 *
 * Since: 2.64
 */
GMemoryMonitor *
g_memory_monitor_dup_default (void)
{
  return g_object_ref (_g_io_module_get_default (G_MEMORY_MONITOR_EXTENSION_POINT_NAME,
                                                 "GIO_USE_MEMORY_MONITOR",
                                                 NULL));
}

static void
g_memory_monitor_default_init (GMemoryMonitorInterface *iface)
{
  /**
   * GMemoryMonitor::low-memory-warning:
   * @monitor: a #GMemoryMonitor
   * @level: the #GMemoryMonitorWarningLevel warning level
   *
   * Emitted when the system is running low on free memory. The signal
   * handler should then take the appropriate action depending on the
   * warning level. See the #GMemoryMonitorWarningLevel documentation for
   * details.
   *
   * Since: 2.64
   */
  signals[LOW_MEMORY_WARNING] =
    g_signal_new (I_("low-memory-warning"),
                  G_TYPE_MEMORY_MONITOR,
                  G_SIGNAL_RUN_LAST,
                  G_STRUCT_OFFSET (GMemoryMonitorInterface, low_memory_warning),
                  NULL, NULL,
                  NULL,
                  G_TYPE_NONE, 1,
                  G_TYPE_MEMORY_MONITOR_WARNING_LEVEL);
}

Line	Count	Source (jump to first uncovered line)
1		/* GIO - GLib Input, Output and Streaming Library
2		*
3		* Copyright 2019 Red Hat, Inc
4		*
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.
9		*
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.
14		*
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/>.
17		*/
18
19		#include "config.h"
20		#include "glib.h"
21		#include "glibintl.h"
22
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"
29		#include "gtask.h"
30
31		/**
32		* SECTION:gmemorymonitor
33		* @title: GMemoryMonitor
34		* @short_description: Memory usage monitor
35		* @include: gio/gio.h
36		*
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/)).
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		* - Free caches
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
50		* - Call [`malloc_trim(3)`](man:malloc_trim) to return cached heap pages to
51		* the kernel (if supported by your libc)
52		*
53		* Note that some actions may not always improve system performance, and so
54		* should be profiled for your application. `malloc_trim()`, for example, may
55		* make future heap allocations slower (due to releasing cached heap pages back
56		* to the kernel).
57		*
58		* See #GMemoryMonitorWarningLevel for details on the various warning levels.
59		*
60		* \|[<!-- language="C" -->
61		* static void
62		* warning_cb (GMemoryMonitor *m, GMemoryMonitorWarningLevel level)
63		* {
64		* g_debug ("Warning level: %d", level);
65		* if (warning_level > G_MEMORY_MONITOR_WARNING_LEVEL_LOW)
66		* drop_caches ();
67		* }
68		*
69		* static GMemoryMonitor *
70		* monitor_low_memory (void)
71		* {
72		* GMemoryMonitor *m;
73		* m = g_memory_monitor_dup_default ();
74		* g_signal_connect (G_OBJECT (m), "low-memory-warning",
75		* G_CALLBACK (warning_cb), NULL);
76		* return m;
77		* }
78		* ]\|
79		*
80		* Don't forget to disconnect the #GMemoryMonitor::low-memory-warning
81		* signal, and unref the #GMemoryMonitor itself when exiting.
82		*
83		* Since: 2.64
84		*/
85
86		/**
87		* GMemoryMonitor:
88		*
89		* #GMemoryMonitor monitors system memory and indicates when
90		* the system is low on memory.
91		*
92		* Since: 2.64
93		*/
94
95		/**
96		* GMemoryMonitorInterface:
97		* @g_iface: The parent interface.
98		* @low_memory_warning: the virtual function pointer for the
99		* #GMemoryMonitor::low-memory-warning signal.
100		*
101		* The virtual function table for #GMemoryMonitor.
102		*
103		* Since: 2.64
104		*/
105
106		G_DEFINE_INTERFACE_WITH_CODE (GMemoryMonitor, g_memory_monitor, G_TYPE_OBJECT,
107		g_type_interface_add_prerequisite (g_define_type_id, G_TYPE_INITABLE))
108
109		enum {
110		LOW_MEMORY_WARNING,
111		LAST_SIGNAL
112		};
113
114		static guint signals[LAST_SIGNAL] = { 0 };
115
116		/**
117		* g_memory_monitor_dup_default:
118		*
119		* Gets a reference to the default #GMemoryMonitor for the system.
120		*
121		* Returns: (not nullable) (transfer full): a new reference to the default #GMemoryMonitor
122		*
123		* Since: 2.64
124		*/
125		GMemoryMonitor *
126		g_memory_monitor_dup_default (void)
127	0	{
128	0	return g_object_ref (_g_io_module_get_default (G_MEMORY_MONITOR_EXTENSION_POINT_NAME,
129	0	"GIO_USE_MEMORY_MONITOR",
130	0	NULL));
131	0	}
132
133		static void
134		g_memory_monitor_default_init (GMemoryMonitorInterface *iface)
135	0	{
136		/**
137		* GMemoryMonitor::low-memory-warning:
138		* @monitor: a #GMemoryMonitor
139		* @level: the #GMemoryMonitorWarningLevel warning level
140		*
141		* Emitted when the system is running low on free memory. The signal
142		* handler should then take the appropriate action depending on the
143		* warning level. See the #GMemoryMonitorWarningLevel documentation for
144		* details.
145		*
146		* Since: 2.64
147		*/
148	0	signals[LOW_MEMORY_WARNING] =
149	0	g_signal_new (I_("low-memory-warning"),
150	0	G_TYPE_MEMORY_MONITOR,
151	0	G_SIGNAL_RUN_LAST,
152	0	G_STRUCT_OFFSET (GMemoryMonitorInterface, low_memory_warning),
153	0	NULL, NULL,
154	0	NULL,
155	0	G_TYPE_NONE, 1,
156	0	G_TYPE_MEMORY_MONITOR_WARNING_LEVEL);
157	0	}

Coverage Report

Created: 2025-07-01 07:09