On 04/20/2010 11:32 AM, Johannes Weiner wrote:
The idea is that it pans out on its own. If the workload changes, new pages get activated and when that set grows too large, we start shrinking it again. Of course, right now this unscanned set is way too large and we can end up wasting up to 50% of usable page cache on false active pages.
Thing is, changing workloads often change back. Specifically, think of a desktop system that is doing work for the user during the day and gets backed up at night. You do not want the backup to kick the working set out of memory, because when the user returns in the morning the desktop should come back quickly after the screensaver is unlocked. The big question is, what workload suffers from having the inactive list at 50% of the page cache? So far the only big problem we have seen is on a very unbalanced virtual machine, with 256MB RAM and 4 fast disks. The disks simply have more IO in flight at once than what fits in the inactive list. This is a very untypical situation, and we can probably solve it by excluding the in-flight pages from the active/inactive file calculation. -- 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/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>