On Wed, 8 Jul 2015, Michal Hocko wrote: > From: Michal Hocko <mhocko@xxxxxxx> > > OOM killer might be triggered explicitly via sysrq+f. This is supposed > to kill a task no matter what e.g. a task is selected even though there > is an OOM victim on the way to exit. This is a big hammer for an admin > to help to resolve a memory short condition when the system is not able > to cope with it on its own in a reasonable time frame (e.g. when the > system is trashing or the OOM killer cannot make sufficient progress) > > E.g. it doesn't make any sense to obey panic_on_oom setting because > a) administrator could have used other sysrqs to achieve the > panic/reboot and b) the policy would break an existing usecase to > kill a memory hog which would be recoverable unlike the panic which > might be configured for the real OOM condition. > > It also doesn't make much sense to panic the system when there is no > OOM killable task because administrator might choose to do additional > steps before rebooting/panicking the system. > > While we are there also add a comment explaining why > sysctl_oom_kill_allocating_task doesn't apply to sysrq triggered OOM > killer even though there is no explicit check and we subtly rely > on current->mm being NULL for the context from which it is triggered. > > Also be more explicit about sysrq+f behavior in the documentation. > > Signed-off-by: Michal Hocko <mhocko@xxxxxxx> Nack, this is already handled by patch 2 in my series. I understand that the titles were wrong for patches 2 and 3, but it doesn't mean we need to add hacks around the code before organizing this into struct oom_control or completely pointless comments and printks that will fill the kernel log. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>