On Tue, 24 May 2011, KOSAKI Motohiro wrote: > > > Also, this patch move finding sacrifice child logic into > > > select_bad_process(). It's necessary to implement adequate > > > no root bonus recalculation. and it makes good side effect, > > > current logic doesn't behave as the doc. > > > > > > > This is unnecessary and just makes the oom killer egregiously long. We > > are already diagnosing problems here at Google where the oom killer holds > > tasklist_lock on the readside for far too long, causing other cpus waiting > > for a write_lock_irq(&tasklist_lock) to encounter issues when irqs are > > disabled and it is spinning. A second tasklist scan is simply a > > non-starter. > > > > [ This is also one of the reasons why we needed to introduce > > mm->oom_disable_count to prevent a second, expensive tasklist scan. ] > > You misunderstand the code. Both select_bad_process() and oom_kill_process() > are under tasklist_lock(). IOW, no change lock holding time. > A second iteration through the tasklist in select_bad_process() will extend the time that tasklist_lock is held, which is what your patch does. -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>