begin quoting Tracy R Reed as of Thu, May 31, 2007 at 01:38:47PM -0700: > kelsey hudson wrote: > >Having a lot of physical memory is definitely important, but having an > >appropriately-sized swap file or device is equally important. Swapping > >is almost a necessity in a modern system. It's no longer a way to get > >stale pages out of memory, but in a lot of cases, a very important way > >to get contiguous blocks of free memory back. Memory fragmentation can > >be a big problem, no matter how much physical RAM you have. If you have > > How is memory fragmentation a problem when memory is random access?
Well, malloc() wants to return continguous memory, yes? I would think that an MMU ought to be able to handle disjoint pages. > Lately I have taken to running machines with no swap at all because it > is better to have a process which is spinning out of control die than to > have the machine swap itself to death and require someone to put their Um, "to death"? I think that what I think you mean is not what I think you think you mean. > hands on the machine to reboot it (or, a better case, get on the xen > virtual console). If it's not a desktop, you shouldn't need to reboot it. Then again, if it's a desktop, you shouldn't need to reboot it either. I get very annoyed when I have to log out and lose my gazillion virtual desktop and bazillian running applications... > Haven't had any problems at all running without swap > and it has saved us a few times. Given that we have more RAM now in a machine on average than we had RAM + disk on a high-end machine 15 years ago... running w/o swap shouldn't be impossible. > Disks are still so slow compared to the > size of both disks and RAM these days that if you are swapping even 512M > of working set you are in real trouble usually. You want to swap out memory to disk so you can use more memory for disk caching. -- Approaching a year log-in time on the desktop. Stewart Stremler -- [email protected] http://www.kernel-panic.org/cgi-bin/mailman/listinfo/kplug-list
