nfs_getpages: error 4

Eugene Grosbein eugen at
Sat Mar 5 12:13:17 UTC 2016

05.03.2016 18:21, Dmitry Sivachenko пишет:
> 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.

Eugene Grosbein

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