> On Tue, Oct 19, 2010 at 10:21 AM, KOSAKI Motohiro > <kosaki.motohiro@xxxxxxxxxxxxxx> wrote: > >> On Tue, Oct 19, 2010 at 9:57 AM, KOSAKI Motohiro > >> <kosaki.motohiro@xxxxxxxxxxxxxx> wrote: > >> >> > I think there are two bugs here. > >> >> > The raid1 bug that Torsten mentions is certainly real (and has been around > >> >> > for an embarrassingly long time). > >> >> > The bug that I identified in too_many_isolated is also a real bug and can be > >> >> > triggered without md/raid1 in the mix. > >> >> > So this is not a 'full fix' for every bug in the kernel :-), but it could > >> >> > well be a full fix for this particular bug. > >> >> > > >> >> > >> >> Can we just delete the too_many_isolated() logic? (Crappy comment > >> >> describes what the code does but not why it does it). > >> > > >> > if my remember is correct, we got bug report that LTP may makes misterious > >> > OOM killer invocation about 1-2 years ago. because, if too many parocess are in > >> > reclaim path, all of reclaimable pages can be isolated and last reclaimer found > >> > the system don't have any reclaimable pages and lead to invoke OOM killer. > >> > We have strong motivation to avoid false positive oom. then, some discusstion > >> > made this patch. > >> > > >> > if my remember is incorrect, I hope Wu or Rik fix me. > >> > >> AFAIR, it's right. > >> > >> How about this? > >> > >> It's rather aggressive throttling than old(ie, it considers not lru > >> type granularity but zone ) > >> But I think it can prevent unnecessary OOM problem and solve deadlock problem. > > > > Can you please elaborate your intention? Do you think Wu's approach is wrong? > > No. I think Wu's patch may work well. But I agree Andrew. > Couldn't we remove the too_many_isolated logic? If it is, we can solve > the problem simply. > But If we remove the logic, we will meet long time ago problem, again. > So my patch's intention is to prevent OOM and deadlock problem with > simple patch without adding new heuristic in too_many_isolated. But your patch is much false positive/negative chance because isolated pages timing and too_many_isolated_zone() call site are in far distance place. So, if anyone don't say Wu's one is wrong, I like his one. -- 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