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... -- 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>