kernel-2.6.9-22.0.1.EL The fork() call time grows linearly based on amount of SysV memory attached to the process. Fix available upstream: http://www.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=d992895ba2b27cf5adf1ba0ad6d27662adc54c5e Upstream discussion: http://groups.google.com/group/linux.kernel/browse_thread/thread/937a999061644f1d/be39ede8f991e847
Support has received calls from customers of Ontario Systems, who recommend running kernels with the lazy fork patch. For apps that use large shared memory spaces and fork to service each request, the performance impact can be orders of magnitude. The downside is that it's possible to have an OOM condition when the app accesses a new part of the shared segment and the kernel needs to copy a PTE, a very long time after the fork itself, thus hiding the cause. If we implement this, we should at least add an appropriate error message in oom-killer as well.
*** This bug has been marked as a duplicate of 185386 ***