Freebsd 8.0 kmem map too small

[Steve Polyack]

On 05/10/10 11:55, Mike Andrews wrote:
> On 5/5/10 11:19 AM, Freddie Cash wrote:
>> On Tue, May 4, 2010 at 11:32 PM, Giulio Ferro<auryn at zirakzigil.org>  
>> wrote:
>>
>>> Giulio Ferro wrote:
>>>
>>>> Thanks, I'll try these settings.
>>>>
>>>> I'll keep you posted.
>>>>
>>>
>>> Nope, it's happened again... Now I've tried to rise vm.kmem_size to 
>>> 6G...
>>> I'm really astounded at how unstable zfs is, it's causing me a lot of
>>> problem.
>>> Why isn't it stated in the handbook that zfs isn't up to production 
>>> yet?
>>>
>>
>> As with everything related to computers, it all depends on your uses.
>
> Sorry to semi-hijack this, but...  I'm also running into frequent 
> "kmem_map too small" panics on 8-STABLE, such as:
>
> panic: kmem_malloc(131072): kmem_map too small: 2023780352 total 
> allocated
> panic: kmem_malloc(131072): kmem_map too small: 2011525120 total 
> allocated
> panic: kmem_malloc(114688): kmem_map too small: 1849356288 total 
> allocated
> panic: kmem_malloc(114688): kmem_map too small: 1849356288 total 
> allocated
> panic: kmem_malloc(114688): kmem_map too small: 1849356288 total 
> allocated
> panic: kmem_malloc(131072): kmem_map too small: 2020409344 total 
> allocated
> panic: kmem_malloc(536576): kmem_map too small: 2022957056 total 
> allocated
>
> (those are over the course of 3-4 days)
>
> On this specific system, it has 32 GB physical memory and has 
> vfs.zfs.arc_max="2G" and vm.kmem_size="64G" in /boot/loader.conf.  The 
> latter was added per earlier suggestions on this list, but appears to 
> be ignored as "sysctl vm.kmem_size" returns about 2 GB (2172452864) 
> anyway.
>
>
As Artem stated in another reply, you will need to set vm.kmem_size 
slightly under 2x the physical memory.  The kernel will default to 2GB 
if you pass this limit.  1.5x physical memory size should be sufficient, 
so try "48G" and verify that it gets set correctly on the next boot.