svn commit: r242847 - in head/sys: i386/include kern

[Alfred Perlstein]

On Nov 10, 2012, at 3:04 PM, Andre Oppermann <andre at freebsd.org> wrote:

> On 10.11.2012 23:24, Alfred Perlstein wrote:
>> On 11/10/12 11:18 AM, Andre Oppermann wrote:
>>> On 10.11.2012 19:04, Peter Wemm wrote:
>>>> This is complicated but we need a simple user visible view of it.  It
>>>> really needs to be something like "nmbclusters defaults to 6% of
>>>> physical ram, with machine dependent limits".  The MD limits are bad
>>>> enough, and using bogo-units like "maxusers" just makes it worse.
>>> 
>>> Yes, that would be optimal.
>>> 
>> No it would not.
>> 
>> I used to be able to tell people "hey just try increasing maxusers" and they would and suddenly the
>> box would be OK.
>> 
>> Now I'll have to remember 3,4,5,10,20x tunable to increase?
> 
> No.  The whole mbuf and cluster stuff isn't allocated or reserved
> at boot time.  We simply need a limit to prevent it from exhausting
> all available kvm / physical memory whichever is less.
> 
> Other than that there is no relation to maxusers except historic
> behavior.
> 
> So the ideal mbuf limit is just short of keeling the kernel over
> no matter what maxusers says.  There also isn't much to tune then
> as the only fix would be to add more physical ram.

I think that makes sense.  If you have ideas please look into it. 


-Alfred