> When a task is chosen for oom kill, the oom killer first attempts to > sacrifice a child not sharing its parent's memory instead. Unfortunately, > this often kills in a seemingly random fashion based on the ordering of > the selected task's child list. Additionally, it is not guaranteed at all > to free a large amount of memory that we need to prevent additional oom > killing in the very near future. > > Instead, we now only attempt to sacrifice the worst child not sharing its > parent's memory, if one exists. The worst child is indicated with the > highest badness() score. This serves two advantages: we kill a > memory-hogging task more often, and we allow the configurable > /proc/pid/oom_adj value to be considered as a factor in which child to > kill. > > Reviewers may observe that the previous implementation would iterate > through the children and attempt to kill each until one was successful and > then the parent if none were found while the new code simply kills the > most memory-hogging task or the parent. Note that the only time > oom_kill_task() fails, however, is when a child does not have an mm or has > a /proc/pid/oom_adj of OOM_DISABLE. badness() returns 0 for both cases, > so the final oom_kill_task() will always succeed. > > Acked-by: Rik van Riel <riel@xxxxxxxxxx> > Acked-by: Nick Piggin <npiggin@xxxxxxx> > Acked-by: Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx> > Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> > Reviewed-by: Minchan Kim <minchan.kim@xxxxxxxxx> > Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx> > Signed-off-by: David Rientjes <rientjes@xxxxxxxxxx> ack -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>