> On 05 Mar 2016, at 15:13, Eugene Grosbein <eugen at grosbein.net>
wrote:
>
> 05.03.2016 18:21, Dmitry Sivachenko ?????:
>> Hello,
>>
>> I am running a number of machines with /home mounted via nfs (FreeBSD
10.3-PRERELEASE #0 r294799, rw,bg,intr,soft).
>>
>> Sometimes I get the following messages in syslog:
>>
>> nfs_getpages: error 4
>> vm_fault: pager read error, pid NNN (myprog)
>>
>> After that I see I lot of processes stuck in "pfault" state
(these are computational processes which use some files from NFS mount), they
use 0% of CPU after that.
>>
>> On NFS server machine I see nothing strange in logs. procstat -kk for
such stuck processes shows:
>> PID TID COMM TDNAME KSTACK
>> 85274 102056 myprog - mi_switch+0xbe
sleepq_wait+0x3a _sleep+0x287 vm_waitpfault+0x8a vm_fault_hold+0xdd0
vm_fault+0x77 trap_pfault+0x180 trap+0x52c calltrap+0x8
>>
>>
>> What can be the reason of this?
>
> For example, if some processes running on NFS server box modify some files
"in-place"
> and these files are opened by processes running on NFS client, that could
be the reason.
> If so, change this so processes updating such files create new temporary
versions of them first
> and then rename them atomically.
>
This should not be the case: users are working only on NFS clients.
Moreover, the nature of computations is so that each process uses it's own
set of files.
(Forgot to mention in my previous e-mail that these processes can't be
stopped even with kill -9)