Further Followup - Behaviour with Swap Enabled -------------------------------------------------------------
After posting this bug, I created swap partition on a spare ~1GB disk partition. (Who needs HP "Quickplay" anyway?) The results were interesting ... I noticed over the course of 48 hours or so of uptime, with regular use of the KDE desktop, that the swap was slowly consumed. In general, under typical load 'htop' would show 500MB used, 1500MB cache (of 2GB physical), and 'x' amount of swap used, where 'x' slowly increased over the time the system was active. This suggests something is leaking memory, or leaking something. But the weird thing is that it is not showing up as memory allocated to a process in 'htop' or 'top'. While the system was up the swap was slowly but steadily consumed. When I hit 100% swap usage, a normal system activity (starting Oracle net- listener) caused the classic disk thrashing symptoms described above, and the load average to spike. The system once again became unresponsive and had to be reboot via the magic-sysrq RSEIUB routine. What I do not understand is that immediately prior to this incident, while swap was close to 100% full, 1500MB of memory was still shown as cached. Surely if memory was short cached blocks would be evicted? Can someone explain this behaviour to me? I do not understand the VM subsystem well enough to make sense of this situation, where most of memory is used for cache, but something is leaking in some way and filling swap. Mysteries include: - What is the disk activity when the incident occurs? Clearly this disk I/O starves other processes and causes the high load average. I have no idea what is causing this? Paging of some sort? Even with no swap enabled? - How can swap slowly be consumed without the memory usage being accounted to some user-space process? I believe if I restart my X session, the accumulated leak is freed, but I am not 100% sure of this. - How can we have 75% of physical memory used for cache, yet experience what appears to be an out of memory event of some sort? Why is the cache not evicted? - Why is swap even used when there is cache in memory? Shouldn't the VM subsystem evict the cached blocked before hitting swap? -- High load average, disk read, no apparent reason - 2.6.28-11 https://bugs.launchpad.net/bugs/367377 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
