kern/175950: Possible deadlock in zfs after long uptime

[Andriy Gapon]

The following reply was made to PR kern/175950; it has been noted by GNATS.

From: Andriy Gapon <avg at FreeBSD.org>
To: bug-followup at FreeBSD.org, pascal.guitierrez at gmail.com
Cc:  
Subject: Re: kern/175950: Possible deadlock in zfs after long uptime
Date: Fri, 08 Feb 2013 08:26:03 +0200

 Thank you for the report.
 
 You seem to have run into a problem that is triggered by either low available
 physical memory or low KVA.
 
 r242859 on stable/8 branch may reduce chances of the problem.  Unfortunately,
 there is no complete resolution at the moment.
 If you are interested, some technical details could be found here:
 http://article.gmane.org/gmane.os.freebsd.stable/84981
 
 Could you please also provide output of the following sysctls (for completeness
 sake):
 vm.stats
 vm.kmem_size
 vm.kmem_map_size
 vm.kmem_map_free
 
 P.S. The bad thread in your report:
  1963 100308 nfsd             nfsd: service    mi_switch+0x176 sleepq_wait+0x42
 _sleep+0x317 arc_lowmem+0x77 kmem_malloc+0xc1 uma_large_malloc+0x4a malloc+0xd7
 arc_get_data_buf+0xb5 arc_read_nolock+0x1ec arc_read+0x93 dbuf_read+0x452
 dmu_tx_check_ioerr+0x9a dmu_tx_count_write+0x29c dmu_tx_hold_write+0x4a
 zfs_freebsd_write+0x372 VOP_WRITE_APV+0xb2 nfsrv_write+0x969 nfssvc_program+0x1a6
 -- 
 Andriy Gapon