Date: Sat, 5 Mar 2016 15:32:04 +0300 From: Dmitry Sivachenko <trtrmitya@gmail.com> To: Eugene Grosbein <eugen@grosbein.net> Cc: FreeBSD Stable ML <stable@freebsd.org> Subject: Re: nfs_getpages: error 4 Message-ID: <550ADE4F-9F60-44FB-BF07-A1384A6B7B1A@gmail.com> In-Reply-To: <56DACD4E.3070905@grosbein.net> References: <A2A32332-4D9D-40DF-9DEC-EE9000879416@gmail.com> <56DACD4E.3070905@grosbein.net>
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> On 05 Mar 2016, at 15:13, Eugene Grosbein <eugen@grosbein.net> wrote: >=20 > 05.03.2016 18:21, Dmitry Sivachenko =D0=BF=D0=B8=D1=88=D0=B5=D1=82: >> Hello, >>=20 >> I am running a number of machines with /home mounted via nfs (FreeBSD = 10.3-PRERELEASE #0 r294799, rw,bg,intr,soft). >>=20 >> Sometimes I get the following messages in syslog: >>=20 >> nfs_getpages: error 4 >> vm_fault: pager read error, pid NNN (myprog) >>=20 >> 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. >>=20 >> 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 >>=20 >>=20 >> What can be the reason of this? >=20 > 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. >=20 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)
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