On Thu, Feb 28, 2008 at 6:13 AM, Alan Cox <alan@xxxxxxxxxxxxxxxxxxx> wrote: > > > That sounds like a non starter. What if the box is busy, what if the > > > daemon or something you touch needs memory and causes paging ? > > > > The daemon runs mlock'd anyway, so there won't be any need for paging > > mlock does not guarantee anything of that form. A syscall by an mlocked > process which causes a memory allocation can cause paging of another > process on the system. > > > > there. As for responsiveness under heavy load, I'm not quite sure I get > > your meaning. On my system, at least, the only way I have managed to > > decrease responsiveness noticeably is to cause a lot of I/O operations > > It depends a lot on hardware but you can certainly get user space delays > in seconds as an extreme worst case. I don't know the details, but I believe the Linux-HA heartbeat daemons take significant effort to eliminate unexpected delays. See http://www.linux-ha.org/ Lars Marowsky-Bree of Novell is extremely involved in the project and he at least occasionally posts on LKML. I've cc'ed him. Greg -- Greg Freemyer Litigation Triage Solutions Specialist http://www.linkedin.com/in/gregfreemyer First 99 Days Litigation White Paper - http://www.norcrossgroup.com/forms/whitepapers/99%20Days%20whitepaper.pdf The Norcross Group The Intersection of Evidence & Technology http://www.norcrossgroup.com -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
