Re: kern/45946: Kernel locks up in VMEM system

[Lars Heidieker <lars%heidieker.de@localhost>]

The following reply was made to PR kern/45946; it has been noted by GNATS.

From: Lars Heidieker <lars%heidieker.de@localhost>
To: gnats-bugs%NetBSD.org@localhost
Cc: 
Subject: Re: kern/45946: Kernel locks up in VMEM system
Date: Wed, 08 Feb 2012 15:09:45 +0100

 On 02/08/2012 02:05 PM, Matthias Scheler wrote:
 > The following reply was made to PR kern/45946; it has been noted by GNATS.
 > 
 > From: Matthias Scheler <tron%zhadum.org.uk@localhost>
 > To: NetBSD GNATS <gnats-bugs%NetBSD.org@localhost>
 > Cc: 
 > Subject: Re: kern/45946: Kernel locks up in VMEM system
 > Date: Wed, 8 Feb 2012 13:04:52 +0000
 > 
 >  On Wed, Feb 08, 2012 at 08:05:03AM +0000, Matthias Scheler wrote:
 >  >  >  can you check the version of src/sys/arch/i386/include/param.h if it
 >  >  >  is 1.75 because a patch sizing the arena went in 3 1/2 days ago.
 >  >  >  The behavior you see is that the kmem_arena runs out of space and the
 >  >  >  pagedaemon tries hard too free something.
 >  >  
 >  >  I'm afraid that I already have version 1.75:
 >  >  
 >  >  tron@lyssa:~>grep NetBSD /usr/src/sys/arch/i386/include/param.h 
 >  >  /*      $NetBSD: param.h,v 1.75 2012/02/04 17:56:16 para Exp $  */
 >  >  
 >  >  I've also tried to reduce the amount of memory of the virtual machine
 >  >  to 2GB and it still locked up.
 >  
 >  Lars Heidieker suggested the following change:
 >  
 >  Index: param.h
 >  ===================================================================
 >  RCS file: /cvsroot/src/sys/arch/i386/include/param.h,v
 >  retrieving revision 1.75
 >  diff -u -r1.75 param.h
 >  --- param.h 4 Feb 2012 17:56:16 -0000       1.75
 >  +++ param.h 8 Feb 2012 13:00:59 -0000
 >  @@ -129,7 +129,7 @@
 >    * logical pages.
 >    */
 >   #define    NKMEMPAGES_MIN_DEFAULT  ((8 * 1024 * 1024) >> PAGE_SHIFT)
 >  -#define    NKMEMPAGES_MAX_DEFAULT  ((280 * 1024 * 1024) >> PAGE_SHIFT)
 >  +#define    NKMEMPAGES_MAX_DEFAULT  ((360 * 1024 * 1024) >> PAGE_SHIFT)
 >   
 >   /*
 >    * Mach derived conversion macros
 >  
 >  This change indeed fixes the problem on my machine with 3GB and 6 cores.
 >  I have however no idea what the impact on different configurations in
 >  particukar with only little memory will be.
 >  
 >
 
 The problem shows up on machines with large physical memory and limited
 kva, where physical memory >> kva.
 We might want to consider to do less quantum caching on the
 kmem_va_arena for such machines.
 
 Lars