On Tue, 01 Apr 2014 15:02:31 -0700 Davidlohr Bueso <davidlohr@xxxxxx> wrote: > On Tue, 2014-04-01 at 14:48 -0700, Andrew Morton wrote: > > On Tue, 1 Apr 2014 17:41:54 -0400 KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxx> wrote: > > > > > >> > Hmmm so 0 won't really work because it could be weirdly used to disable > > > >> > shm altogether... we cannot go to some negative value either since we're > > > >> > dealing with unsigned, and cutting the range in half could also hurt > > > >> > users that set the limit above that. So I was thinking of simply setting > > > >> > SHMMAX to ULONG_MAX and be done with it. Users can then set it manually > > > >> > if they want a smaller value. > > > >> > > > > >> > Makes sense? > > > >> > > > >> I don't think people use 0 for disabling. but ULONG_MAX make sense to me too. > > > > > > > > Distros could have set it to [U]LONG_MAX in initscripts ten years ago > > > > - less phone calls, happier customers. And they could do so today. > > > > > > > > But they haven't. What are the risks of doing this? > > > > > > I have no idea really. But at least I'm sure current default is much worse. > > > > > > 1. Solaris changed the default to total-memory/4 since Solaris 10 for DB. > > > http://www.postgresql.org/docs/9.1/static/kernel-resources.html > > > > > > 2. RHEL changed the default to very big size since RHEL5 (now it is > > > 64GB). Even tough many box don't have 64GB memory at that time. > > > > Ah-hah, that's interesting info. > > > > Let's make the default 64GB? > > But again, yet another arbitrary value... Well, I'm assuming 64GB==infinity. It *was* infinity in the RHEL5 timeframe, but infinity has since become larger so pickanumber. -- 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>