gio.memory_monitor_mixin

Module for [MemoryMonitor] interface mixin

Templates 2

tmplMemoryMonitorT()

[gio.memory_monitor.MemoryMonitor] 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

(API documentation).

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)) 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 [gio.types.MemoryMonitorWarningLevel] for details on the various warning levels.

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 signal@Gio.MemoryMonitor::low-memory-warning signal, and unref the [gio.memory_monitor.MemoryMonitor] itself when exiting.

Functions
gulong connectLowMemoryWarning(T)(T callback, Flag!"After" after = No.After) if (isCallable!T && is(ReturnType!T == void) && (Parameters!T.length < 1 || (ParameterStorageClassTuple!T[0] == ParameterStorageClass.none && is(Parameters!T[0] == gio.types.MemoryMonitorWarningLevel))) && (Parameters!T.length < 2 || (ParameterStorageClassTuple!T[1] == ParameterStorageClass.none && is(Parameters!T[1] : gio.memory_monitor.MemoryMonitor))) && Parameters!T.length < 3)

Connect to LowMemoryWarning signal.

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.

Parameters

callbacksignal callback delegate or function to connect void callback(gio.types.MemoryMonitorWarningLevel level, gio.memory_monitor.MemoryMonitor memoryMonitor) level the #GMemoryMonitorWarningLevel warning level (optional) memoryMonitor the instance the signal is connected to (optional)
afterYes.After to execute callback after default handler, No.After to execute before (default)

Returns

Signal ID
tmplMemoryMonitorGidBuilderT()