Re: panic: kmem_malloc(131072): kmem_map too small (AMD64)

From: Kris Kennaway <kris_at_FreeBSD.org>
Date: Thu, 27 Sep 2007 00:12:39 +0200
Darren Reed wrote:
> Kris Kennaway wrote:
>> Darren Reed wrote:
>>> Kris Kennaway wrote:
>>>> ...
>>>> Well yes, that is one hypothesis, but the evidence points elsewhere 
>>>> as well.  Prior the change you reference, some of my zfs machines 
>>>> would run for weeks before hitting a load pattern that exhausted 
>>>> their kmem_map and triggered the panic.  Also unless I have missed 
>>>> it I am not seeing the sudden flood of panic reports that may 
>>>> indicate sudden breakage.  It is quite possible that this particular 
>>>> report has nothing to do with the recent change.
>>>
>>> Indeed.
>>>
>>> But here's something else to ponder...
>>>
>>> I've been using ZFS since it was internal beta at Sun, at first on 
>>> i386 and later on amd64.
>>> I've never run into this kind of panic on Solaris.  System can get 
>>> very slow, yes, with
>>> ZFS hogging lots of memory, but it never panic'd because of it.
>>>
>>> We need to come up with a strategy here to solve this problem, be it 
>>> fixing the kmem
>>> virtual memory or fixing zfs.
>>
>> Yes, Solaris does something architecturally different because it is 
>> apparently acceptable for zfs to use gigabytes of memory by default.
> 
> Well, if you were designing a file system for servers, is there any
> reason that you wouldn't try to use all of the RAM available?

No, but it's different to what FreeBSD does.  Especially on i386.

Kris
Received on Wed Sep 26 2007 - 20:12:39 UTC

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