Re: [Patch] ipc: HARD_MSGMAX should be higher not lower on 64bit

Serge E. Hallyn
2009-12-11T14:44:50Z

Quoting Amerigo Wang (amwang@redhat.com):
> It looks weird that we have HARD_MSGMAX lower on 64bit than on 32bit,
> since usually 64bit machines have more memory than 32bit machines.

It does look like this may have been an accident.

> Making it higher on 64bit seems reasonable, and keep the original
> number on 32bit.
>
> Cc: Serge E. Hallyn <serue@us.ibm.com>
> Cc: Cedric Le Goater <clg@fr.ibm.com>
> Signed-off-by: WANG Cong <amwang@redhat.com>
>
> ---
> diff --git a/include/linux/ipc_namespace.h b/include/linux/ipc_namespace.h
> index e408722..07baa38 100644
> --- a/include/linux/ipc_namespace.h
> +++ b/include/linux/ipc_namespace.h
> @@ -87,7 +87,7 @@ extern int mq_init_ns(struct ipc_namespace *ns);
> /* default values */
> #define DFLT_QUEUESMAX 256 /* max number of message queues */
> #define DFLT_MSGMAX 10 /* max number of messages in each queue */
> -#define HARD_MSGMAX (131072/sizeof(void *))
> +#define HARD_MSGMAX (32768*sizeof(void *)/4)

why /4 ? You're now making it much smaller for 32-bit than it
used to be?

> #define DFLT_MSGSIZEMAX 8192 /* max message size */
> #else
> static inline int mq_init_ns(struct ipc_namespace *ns) { return 0; }