[gjs] Ratelimit RSS-triggered GCs

[Giovanni Campagna <gcampagna src gnome org>]

commit 791b1a33424897549f487eb75a80f13c4f94437a
Author: Giovanni Campagna <gcampagna src gnome org>
Date:   Fri Apr 11 18:38:57 2014 +0200

    Ratelimit RSS-triggered GCs
    
    When loading a lot of data in memory (for example in the shell
    opening the overview, which loads all the desktop files and icons)
    the RSS can increase a lot, so we would trigger GCs continously
    without any hope of freeing memory, so ratelimit full GCs to at
    most one every 5 frames.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=728048

 gjs/jsapi-util.cpp |    9 +++++++++
 1 files changed, 9 insertions(+), 0 deletions(-)
---
diff --git a/gjs/jsapi-util.cpp b/gjs/jsapi-util.cpp
index b360cf2..0f62abb 100644
--- a/gjs/jsapi-util.cpp
+++ b/gjs/jsapi-util.cpp
@@ -1180,6 +1180,7 @@ _linux_get_self_process_size (gulong *vm_size,
 }
 
 static gulong linux_rss_trigger;
+static gint64 last_gc_time;
 #endif
 
 void
@@ -1190,6 +1191,13 @@ gjs_gc_if_needed (JSContext *context)
         /* We initiate a GC if VM or RSS has grown by this much */
         gulong vmsize;
         gulong rss_size;
+        gint64 now;
+
+        /* We rate limit GCs to at most one per 5 frames.
+           One frame is 16666 microseconds (1000000/60)*/
+        now = g_get_monotonic_time();
+        if (now - last_gc_time < 5 * 16666)
+            return;
 
         _linux_get_self_process_size (&vmsize, &rss_size);
 
@@ -1206,6 +1214,7 @@ gjs_gc_if_needed (JSContext *context)
         if (rss_size > linux_rss_trigger) {
             linux_rss_trigger = (gulong) MIN(G_MAXULONG, rss_size * 1.25);
             JS_GC(JS_GetRuntime(context));
+            last_gc_time = now;
         } else if (rss_size < (0.75 * linux_rss_trigger)) {
             /* If we've shrunk by 75%, lower the trigger */
             linux_rss_trigger = (rss_size * 1.25);