le9-patch

The amount of dirty pages the kernel keeps in RAM is configurable through sysctl. If the buffer is full any further write blocks the process. If you have less free RAM than the allowed dirty page buffer what you said is correct though. There is a new patch[1] that allows to set a soft and hard minimum of RAM reserved for clean pages. This fixes the problem almost completely even under the heaviest loads. cgroups like a silbling post mentioned can also help by setting soft limits for heavy background tasks like compile jobs. Setting a soft limit will give them as much RAM as is available, or swap them out completely when things are heavily contented, effectively pausing the processes. It requires some setting up though, so it's not a solution for all cases, but it can make sense even without the thrashing problem. [1]: https://github.com/h

While that is true, you can invoke the OOM killer at any time you want by pressing Ctrl+Alt+Print("SysRq")+F(uck?). Given the letter they picked it seems like they're fully aware of the deficiency. As to why it was never really addressed, that's a good question. The recent le9[1] patch addresses the most annoying symptom of running out of memory by keeping some amount of RAM reserved for clean pages (like static program code) so that those won't get swapped in and out so much. That greatly improves responsiveness under low memory conditions. [1]: https://github.com/hakavlad/le9-patch