(panic) Lots of network memory needed

[dave baukus]

I'm fairly sure that you are out of kernel virtual memory.
Look at kern/kern_malloc.c kmeminit (); you can play w/ VM_KMEM_SIZE_MAX
or  TUNABLE_INT_FETCH("kern.vm.kmem.size", &vm_kmem_size);

      /*
          * Try to auto-tune the kernel memory size, so that it is
          * more applicable for a wider range of machine sizes.
          * On an X86, a VM_KMEM_SIZE_SCALE value of 4 is good, while
          * a VM_KMEM_SIZE of 12MB is a fair compromise.  The
          * VM_KMEM_SIZE_MAX is dependent on the maximum KVA space
          * available, and on an X86 with a total KVA space of 256MB,
          * try to keep VM_KMEM_SIZE_MAX at 80MB or below.
          *
          * Note that the kmem_map is also used by the zone allocator,
          * so make sure that there is enough space.
          */
         vm_kmem_size = VM_KMEM_SIZE;
         mem_size = cnt.v_page_count * PAGE_SIZE;

#if defined(VM_KMEM_SIZE_SCALE)
         if ((mem_size / VM_KMEM_SIZE_SCALE) > vm_kmem_size)
                 vm_kmem_size = mem_size / VM_KMEM_SIZE_SCALE;
#endif

#if defined(VM_KMEM_SIZE_MAX)
         if (vm_kmem_size >= VM_KMEM_SIZE_MAX)
                 vm_kmem_size = VM_KMEM_SIZE_MAX;
#endif

         /* Allow final override from the kernel environment */
         TUNABLE_INT_FETCH("kern.vm.kmem.size", &vm_kmem_size);


Karim Fodil-Lemelin wrote:
> Thanks but the system still crashes (FreeBSD 4.9) with 131072. Here is a 
> backtrace showing just that:
> 
> Debugger (msg=0xc02b6cdb "panic") at ../../i386/i386/db_interface.c:321
> 321     }
> (kgdb) bt
> #0  Debugger (msg=0xc02b6cdb "panic") at ../../i386/i386/db_interface.c:321
> #1  0xc016a230 in panic (
>    fmt=0xc02ea380 "pmap_enter: invalid page directory pdir=%#llx, 
> va=%#x\n")
>    at ../../kern/kern_shutdown.c:593
> #2  0xc0283594 in pmap_enter (pmap=0xc0340460, va=4292141056, m=0xc24b2848,
>    prot=7 '\a', wired=1) at ../../i386/i386/pmap.c:1943
> #3  0xc023ddd0 in vm_fault (map=0xc033322c, vaddr=4292141056,
>    fault_type=7 '\a', fault_flags=1) at ../../vm/vm_fault.c:841
> #4  0xc023df0a in vm_fault_wire (map=0xc033322c, start=4292141056,
>    end=4292149248) at ../../vm/vm_fault.c:915
> #5  0xc0240831 in vm_map_pageable (map=0xc033322c, start=4292141056,
>    real_end=4292149248, new_pageable=0) at ../../vm/vm_map.c:1817
> #6  0xc023ea25 in kmem_alloc (map=0xc033322c, size=8192)
>    at ../../vm/vm_kern.c:213
> #7  0xc024a46f in _zget (z=0xdb5c6e80) at ../../vm/vm_zone.c:425
> #8  0xc024a269 in zalloc (z=0xdb5c6e80) at ../../vm/vm_zone.c:60
> #9  0xc0196106 in namei (ndp=0xfa489ef4) at ../../kern/vfs_lookup.c:104
> #10 0xc01614ca in execve (p=0xfa482e00, uap=0xfa489f90)
>    at ../../kern/kern_exec.c:165
> #11 0xc01590a1 in start_init (dummy=0x0) at ../../kern/init_main.c:543
> (kgdb) p nmbclusters
> $1 = 131072
> (kgdb)
> 
> Goran Spirovski - MorEl On.net wrote:
> 
>> AFAIK the number of mbufs (and consequently nmbclusters) has to be a 
>> power
>> of 2, so you should set it to 131072
>>
>> MorEl
>>
>> ----- Original Message ----- From: "Karim Fodil-Lemelin" <kfl at xiphos.ca>
>> To: <freebsd-net at freebsd.org>
>> Sent: Wednesday, June 15, 2005 6:08 PM
>> Subject: (panic) Lots of network memory needed
>>
>>
>>  
>>
>>> Hello,
>>>
>>> From kernel tuning page
>>>   
>>
>> (http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/configtuning-kern 
>>
>> el-limits.html)
>>  
>>
>>> Some sentence about nmbclusters says:
>>>
>>> "Under no circumstances should you specify an arbitrarily high value for
>>>   
>>
>> this parameter as it could lead to a boot time crash."
>>  
>>
>>> Now I want to push the limits where I need 4KB buffer for each of the
>>>   
>>
>> 32000 connections I want this server to handle. If I do the math:
>>  
>>
>>> (32000 (conns) * 4 (KB/buffer) * 2 (buffer/conn)) / 2048 (KB/cluster)
>>>
>>> = 128000 clusters
>>>
>>> So I set this arbitrary high value in loader.conf under
>>>   
>>
>> (kern.ipc.nmbclusters) and no surprises I get panic: pmap_enter 
>> invalid page
>> directory pdir=0x3cb063, va=0xfff800
>>  
>>
>>> (va has a weird address here)
>>>
>>> I know I am pushing the limits here but I have plenty of memory (2GB) on
>>>   
>>
>> this system (after all its just 250MB for network memory ;) and this is
>> mainly just experimentation.
>>  
>>
>>> I would like some pointers toward fixing this. Is there another variable
>>>   
>>
>> tied into this (I guess so)? Could anybody points me to a technical 
>> document
>> that would explain the relationship with that (those) other(s) presumed
>> variable(s)?
>>  
>>
>>> Thank you,
>>>
>>>
>>> Karim
>>>
>>>
>>> _______________________________________________
>>> freebsd-net at freebsd.org mailing list
>>> http://lists.freebsd.org/mailman/listinfo/freebsd-net
>>> To unsubscribe, send any mail to "freebsd-net-unsubscribe at freebsd.org"
>>>   
>>
>>
>>
>>
>>  
>>
> 

-- 
Dave Baukus
dbaukus at chiaro.com			
	Chiaro Networks Ltd.
	Richardson, Texas
	USA