On Mon, Aug 08, 2011 at 09:47:14PM +0800, Peter Zijlstra wrote: > On Sat, 2011-08-06 at 16:44 +0800, Wu Fengguang wrote: > > Add two fields to task_struct. > > > > 1) account dirtied pages in the individual tasks, for accuracy > > 2) per-task balance_dirty_pages() call intervals, for flexibility > > > > The balance_dirty_pages() call interval (ie. nr_dirtied_pause) will > > scale near-sqrt to the safety gap between dirty pages and threshold. > > > > XXX: The main problem of per-task nr_dirtied is, if 10k tasks start > > dirtying pages at exactly the same time, each task will be assigned a > > large initial nr_dirtied_pause, so that the dirty threshold will be > > exceeded long before each task reached its nr_dirtied_pause and hence > > call balance_dirty_pages(). > > > > Signed-off-by: Wu Fengguang <fengguang.wu@xxxxxxxxx> > > --- > > include/linux/sched.h | 7 ++ > > mm/memory_hotplug.c | 3 - > > mm/page-writeback.c | 106 +++++++++------------------------------- > > 3 files changed, 32 insertions(+), 84 deletions(-) > > No fork() hooks? This way tasks inherit their parent's dirty count on > clone(). Ah good point. Here is the quick fix. Thanks, Fengguang --- --- linux-next.orig/kernel/fork.c 2011-08-08 22:11:59.000000000 +0800 +++ linux-next/kernel/fork.c 2011-08-08 22:18:05.000000000 +0800 @@ -1301,6 +1301,9 @@ static struct task_struct *copy_process( p->pdeath_signal = 0; p->exit_state = 0; + p->nr_dirtied = 0; + p->nr_dirtied_pause = 8; + /* * Ok, make it visible to the rest of the system. * We dont wake it up yet. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>