On Fri, 12 Feb 2010, KAMEZAWA Hiroyuki wrote: > > Two VM sysctls, oom dump_tasks and oom_kill_allocating_task, were > > implemented for very large systems to avoid excessively long tasklist > > scans. The former suppresses helpful diagnostic messages that are > > emitted for each thread group leader that are candidates for oom kill > > including their pid, uid, vm size, rss, oom_adj value, and name; this > > information is very helpful to users in understanding why a particular > > task was chosen for kill over others. The latter simply kills current, > > the task triggering the oom condition, instead of iterating through the > > tasklist looking for the worst offender. > > > > Both of these sysctls are combined into one for use on the aforementioned > > large systems: oom_kill_quick. This disables the now-default > > oom_dump_tasks and kills current whenever the oom killer is called. > > > > The oom killer rewrite is the perfect opportunity to combine both sysctls > > into one instead of carrying around the others for years to come for > > nothing else than legacy purposes. > > > > Signed-off-by: David Rientjes <rientjes@xxxxxxxxxx> > > seems reasonable..but how old these APIs are ? Replacement is ok ? > I'm not concerned about /proc/sys/vm/oom_dump_tasks because it was disabled by default and is now enabled by default (unless the user sets this new /proc/sys/vm/oom_kill_quick). So existing users of oom_dump_tasks will just have their write fail but identical behavior as before. /proc/sys/vm/oom_kill_allocating_task is different since it now requires enabling /proc/sys/vm/oom_kill_quick, but I think there are such few users (SGI originally requested it a couple years ago when we started scanning the tasklist for CONSTRAINT_CPUSET in 2.6.24) and the side-effect of not enabling it is minimal, it's just a long delay at oom kill time because they must scan the tasklist. Therefore, I don't see it as a major problem that will cause large disruptions, instead I see it as a great opportunity to get rid of one more sysctl without taking away functionality. > Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> > Thanks! -- 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>