Gio.MemoryMonitor¶

interface

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 (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 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 MemoryMonitor.low-memory-warning signal, and unref the GMemoryMonitor itself when exiting.

Static functions¶

dup_default¶

@staticmethod
def dup_default() -> MemoryMonitor

Gets a reference to the default MemoryMonitor for the system.

Virtual methods¶

do_low_memory_warning¶

def do_low_memory_warning(self, level: MemoryMonitorWarningLevel | int) -> None

the virtual function pointer for the MemoryMonitor::low-memory-warning signal.

Signals¶

low-memory-warning¶

def on_low_memory_warning(self, level: MemoryMonitorWarningLevel) -> None: ...

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 MemoryMonitorWarningLevel documentation for details.

Since the MemoryMonitor is a singleton, this signal will be emitted in the GLib.MainContext.default[global-default main context].