Messages in this thread | | | From | KOSAKI Motohiro <> | Date | Tue, 1 Apr 2014 17:41:54 -0400 | Subject | Re: [PATCH] ipc,shm: increase default size for shmmax |
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>> > 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.
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