On Mon, Nov 20, 2017 at 02:03:44PM +0000, Stefan Hajnoczi wrote: > On Mon, Nov 20, 2017 at 04:41:41PM +0800, Zhong Yang wrote: > > On Fri, Nov 17, 2017 at 01:54:09PM +0000, Stefan Hajnoczi wrote: > > > On Fri, Nov 17, 2017 at 02:23:34PM +0800, Yang Zhong wrote: > > > > @@ -272,6 +273,9 @@ static void *call_rcu_thread(void *opaque) > > > > node->func(node); > > > > } > > > > qemu_mutex_unlock_iothread(); > > > > +#ifdef CONFIG_LINUX > > > > + malloc_trim(0); > > > > +#endif > > > > > > It is important that the rcu thread isn't overzealous in minimizing heap > > > size if that means ordinary malloc(3) calls will experience latency > > > spikes. Please leave a few MB free so that malloc(3) doesn't take the > > > slow path. > > > > > Hello Stefan, > > > > From the Qemu bootup procedure, the qemu malloc chunk memory from OS, not > > from glibc free list which is freed before by Qemu. Maybe there are some > > issues in glibc memory mechanism. I will continue to fine this parameter > > to get better balance, Many thanks! > > I was suggesting malloc_trim(4 * 1024 * 1024) or similar instead of > malloc_trim(0). > Hello Stefan,
Thanks for your suggestion! I tried your suggested changes, malloc_trim(4 * 1024 * 1024), the heap size with this change almost same with malloc_trim(0), thanks! Regards, Yang > Stefan
