> Am I missing the point? I was under the impression that there is a
> well-defined behavior when a Un*x reaches memory resource limits.
> Additional requests for resources are simply denied: currently
> executing processes don't get axed until they segfault, get signalled
> or exit().
>
> How does the population in user space grow? Only a handful of ways
> I can think of:
> - malloc(3), realloc, etc.
> - fork(2)
> - execve(2)
> - ...
- COW shared page being written to
- COW zero page being written to
- the kernel needs more memory (network, nfs, etc)
> Each one will fail if there is insufficient virtual memory, so each
> application is responsible for detecting NULL from malloc(), -1 from
> fork(), and so on, giving it a chance to do other work or exit().
If there's no more memory, nobody will have much of a chance to
do anything. Usually it's kswapd taking up all the CPU time
desparately trying to free something.
Rik.
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