Jeff Davis wrote: > In oom_kill.c, one of the badness calculations is wildly inaccurate. If > memory is shared among child processes, that same memory will be counted > for each child, effectively multiplying the memory penalty by N, where N > is the number of children. > > This makes it almost certain that the parent will always be chosen as > the victim of the OOM killer (assuming any substantial amount memory > shared among the children), even if the parent and children are well > behaved and have a reasonable and unchanging VM size. > > Usually this does not actually alleviate the memory pressure because the > truly bad process is completely unrelated; and the OOM killer must later > kill the truly bad process. > > This trivial patch corrects the calculation so that it does not count a > child's shared memory against the parent. >
Hi, Jeff, 1. grep on the kernel source tells me that shared_vm is incremented only in vm_stat_account(), which is a NO-OP if CONFIG_PROC_FS is not defined. 2. How have you tested these patches? One way to do it would be to use the memory controller and set a small limit on the control group. A memory intensive application will soon see an OOM. I do need to look at OOM kill sanity, my colleagues using the memory controller have reported wrong actions taken by the OOM killer, but I am yet to analyze them. The interesting thing is the use of total_vm and not the RSS which is used as the basis by the OOM killer. I need to read/understand the code a bit more. -- Warm Regards, Balbir Singh Linux Technology Center IBM, ISTL -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/