2010/6/11 David Rientjes <rientjes@xxxxxxxxxx>: > On Thu, 10 Jun 2010, Ryan Wang wrote: > >> Hi all, >> >> I have one question about oom killer: >> If many processes dealing with network communications, >> but due to bad network traffic, the processes have to wait >> for a very long time. And meanwhile they may consume >> some memeory separately for computation. The number >> of such processes may be large. >> >> I wonder whether oom killer will kill these processes >> when the system is under high pressure? >> > > The kernel can deal with "high pressure" quite well, but in some cases > such as when all of your RAM or your memory controller is filled with > anonymous memory and cannot be reclaimed, the oom killer may be called to > kill "something". It prefers to kill something that will free a large > amount of memory to avoid having to subsequently kill additional tasks > when it kills something small first. > > If there are tasks that you'd either like to protect from the oom killer > or always prefer in oom conditions, you can influence its decision-making > from userspace by tuning /proc/<pid>/oom_adj of the task in question. > Users typically set an oom_adj value of "-17" to completely disable oom > killing of pid (the kernel will even panic if it can't find anything > killable as a result of this!), a value of "-16" to prefer that pid gets > killed last, and a value of "15" to always prefer pid gets killed first. > > Lowering a /proc/<pid>/oom_adj value for a pid from its current value (it > inherits its value from the parent, which is usually 0) is only allowed by > root, more specifically, it may only be done by the CAP_SYS_RESOURCE > capability. > > You can refer to Documentation/filesystems/proc.txt for information on > oom_adj. > Thanks all! -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx Please read the FAQ at http://kernelnewbies.org/FAQ
