On Tue, Feb 22, 2011 at 11:03:51AM -0600, Jeffrey Hundstad wrote: > On 02/22/2011 07:28 AM, Andrea Arcangeli wrote: > > Hi Minchan, > > That's my point, we should check if the "thrashing horribly" is really > > a "recently" or if it has always happened before with 2.6.18 and previous. > > I would bet that "thrashing" isn't what he meant. He almost certainly > meant "needless I/O" and nothing to do with swapping. I've seen this > similar report before. This report is almost always gets answered with > a "set your swappiness to an appropriate value" type answer. Or a "your Hmm but swappiness can't help if "needless I/O in the morning after backup" is the problem. So it wouldn't be the right suggestion if "needless I/O is the problem". We need a "vmstat 1" during the "trashing horribly"/"needless I/O" in the morning to be sure. > userspace app needs to get smarter" type answer. I think they are > trying to do the latter, but need some help from the kernel, and that's > what they're trying to do here. That's fine thing. But I got reports indipendent of this thread from friends, asking me how to prevent swapping overnight because of backup, so I connected that report to the above "trashing horribly"/recently. I had no problems personally but may backup runs once (not twice to activate/reference pages). I had no time to investigate this further yet to see if things works ok for me even with a rsync loop activating and referencing everything. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx 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>