From: Michal Hocko <mhocko@xxxxxxxx> When the OOM killer is issued by the administrator by sysrq+f it is expected that a task will be killed to release the memory pressure. Unlike the regular OOM killer the forced one doesn't abort when there is an OOM victim selected. Instead oom_scan_process_thread forces select_bad_process to check this thread. If this happens to be the largest OOM hog then it will be selected again and the forced OOM killer wouldn't make any change in case the current OOM victim is not able terminate and free up resources it is sitting on. This patch makes sure that the forced oom killer will skip over all oom victims (with TIF_MEMDIE) and tasks with fatal_signal_pending on basis that there is no guarantee those tasks are making progress and there is no way to check they will ever make any. It is more conservative to simply try another task. Signed-off-by: Michal Hocko <mhocko@xxxxxxxx> --- mm/oom_kill.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/mm/oom_kill.c b/mm/oom_kill.c index abefeeb42504..2b9dc5129a89 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -326,6 +326,17 @@ static struct task_struct *select_bad_process(struct oom_control *oc, case OOM_SCAN_OK: break; }; + + /* + * If we are doing sysrq+f then it doesn't make any sense to + * check OOM victim or killed task because it might be stuck + * and unable to terminate while the forced OOM might be the + * only option left to get the system back to work. + */ + if (is_sysrq_oom(oc) && (test_tsk_thread_flag(p, TIF_MEMDIE) || + fatal_signal_pending(p))) + continue; + points = oom_badness(p, NULL, oc->nodemask, totalpages); if (!points || points < chosen_points) continue; -- 2.6.4 -- 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>