[tracker-miners] tracker-miner-fs: Use GMemoryMonitor if available

[Carlos Garnacho <carlosg src gnome org>]

commit 191cc5218b53fba85baec1c8c17bb246a74044c0
Author: Carlos Garnacho <carlosg gnome org>
Date:   Sun Aug 30 22:49:20 2020 +0200

    tracker-miner-fs: Use GMemoryMonitor if available
    
    Ensure to return as much memory as possible on memory pressure situations

 src/miners/fs/tracker-main.c | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)
---
diff --git a/src/miners/fs/tracker-main.c b/src/miners/fs/tracker-main.c
index 0c9ed2ac3..c60070d04 100644
--- a/src/miners/fs/tracker-main.c
+++ b/src/miners/fs/tracker-main.c
@@ -444,6 +444,17 @@ cleanup_cb (gpointer user_data)
        return G_SOURCE_REMOVE;
 }
 
+#if GLIB_CHECK_VERSION (2, 64, 0)
+static void
+on_low_memory (GMemoryMonitor            *monitor,
+               GMemoryMonitorWarningLevel level,
+               gpointer                   user_data)
+{
+       if (level > G_MEMORY_MONITOR_WARNING_LEVEL_LOW)
+               malloc_trim (0);
+}
+#endif
+
 static void
 miner_started_cb (TrackerMinerFS *fs)
 {
@@ -930,6 +941,9 @@ main (gint argc, gchar *argv[])
        TrackerEndpointDBus *endpoint;
        TrackerDomainOntology *domain_ontology;
        GCancellable *cancellable;
+#if GLIB_CHECK_VERSION (2, 64, 0)
+       GMemoryMonitor *memory_monitor;
+#endif
        gchar *domain_name, *dbus_name;
 
        main_loop = NULL;
@@ -1115,10 +1129,18 @@ main (gint argc, gchar *argv[])
                tracker_miner_files_set_mtime_checking (TRACKER_MINER_FILES (miner_files), do_mtime_checking);
        }
 
+       g_signal_connect (miner_files, "started",
+                         G_CALLBACK (miner_started_cb),
+                         NULL);
        g_signal_connect (miner_files, "finished",
                          G_CALLBACK (miner_finished_cb),
                          NULL);
 
+#if GLIB_CHECK_VERSION (2, 64, 0)
+       memory_monitor = g_memory_monitor_dup_default ();
+       g_signal_connect (memory_monitor, "low-memory-warning", on_low_memory, NULL);
+#endif
+
        /* Preempt creation of graphs */
        tracker_sparql_connection_update_async (tracker_miner_get_connection (miner_files),
                                                "CREATE SILENT GRAPH tracker:FileSystem; "
@@ -1161,6 +1183,11 @@ main (gint argc, gchar *argv[])
        tracker_sparql_connection_close (sparql_conn);
        g_object_unref (sparql_conn);
 
+#if GLIB_CHECK_VERSION (2, 64, 0)
+       g_signal_handlers_disconnect_by_func (memory_monitor, on_low_memory, NULL);
+       g_object_unref (memory_monitor);
+#endif
+
        g_print ("\nOK\n\n");
 
        return EXIT_SUCCESS;