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Thread-Topic: how to fix an interesting issue with mountd? 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NEURAL_HAM_MEDIUM(-0.96)[-0.960]; R_DKIM_ALLOW(-0.20)[uoguelph.ca:s=selector1]; RWL_MAILSPIKE_POSSIBLE(0.00)[40.107.66.84:from]; FROM_HAS_DN(0.00)[]; RCPT_COUNT_THREE(0.00)[3]; TO_DN_SOME(0.00)[]; R_SPF_ALLOW(-0.20)[+ip4:40.107.0.0/16]; MIME_GOOD(-0.10)[text/plain]; RCVD_TLS_LAST(0.00)[]; DMARC_NA(0.00)[uoguelph.ca]; DWL_DNSWL_LOW(-1.00)[uoguelph.ca:dkim]; RCVD_COUNT_THREE(0.00)[3]; TO_MATCH_ENVRCPT_SOME(0.00)[]; DKIM_TRACE(0.00)[uoguelph.ca:+]; NEURAL_HAM_SHORT(-0.72)[-0.720]; RCVD_IN_DNSWL_NONE(0.00)[40.107.66.84:from]; NEURAL_HAM_LONG(-1.03)[-1.031]; FROM_EQ_ENVFROM(0.00)[]; MIME_TRACE(0.00)[0:+]; SUBJECT_ENDS_QUESTION(1.00)[]; ASN(0.00)[asn:8075, ipnet:40.64.0.0/10, country:US]; FREEMAIL_CC(0.00)[FreeBSD.org,gmail.com]; ARC_ALLOW(-1.00)[microsoft.com:s=arcselector9901:i=1] X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.33 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 02 Jun 2020 02:15:56 -0000 Updated slightly from the previous post...=0A= =0A= Hi,=0A= =0A= I'm posting this one to freebsd-net@ since it seems vaguely similar=0A= to a network congestion problem and thought that network types=0A= might have some ideas w.r.t. fixing it?=0A= =0A= PR#246597 - Reports a problem (which if I understand it is) where a sighup= =0A= is posted to mountd and then another sighup is posted to mountd while=0A= it is reloading exports and the exports are not reloaded again.=0A= --> The simple patch in the PR fixes the above problem, but I think will= =0A= aggravate another one.=0A= For some NFS servers, it can take minutes to reload the exports file(s).=0A= (I believe Peter Erriksonn has a server with 80000+ file systems exported.)= =0A= r348590 reduced the time taken, but it is still minutes, if I recall correc= tly.=0A= --> If you apply the patch in the PR and sighups are posted to mountd as=0A= often as it takes to reload the exports file(s), it will simply relo= ad the=0A= exports file(s) over and over and over again, instead of processing= =0A= Mount RPC requests.=0A= The current code ignores sighup(s) posted while a reload is in progr= ess,=0A= but could still suffer a similar fate if sighups are posted to mount= d just=0A= after a reload completes, over and over..=0A= (I vaguely recall someone reporting that mountd spent hours just rel= oading=0A= exports repeatedly.)=0A= =0A= So, finally to the interesting part...=0A= - It seems that the code needs to be changed so that it won't "forget"=0A= sighup(s) posted to it, but it should not reload the exports file(s) too= =0A= frequently.=0A= --> My thoughts are something like:=0A= - Note that sighup(s) were posted while reloading the exports file(s) and= =0A= do the reload again, after some minimum delay.=0A= --> The minimum delay might only need to be 1second to allow some=0A= RPCs to be processed before reload happens again.=0A= Or=0A= --> The minimum delay could be some fraction of how long a reload takes= .=0A= (The code could time the reload and use that to calculate how lon= g to=0A= delay before doing the reload again.)=0A= =0A= Any ideas or suggestions? rick=0A= ps: I've actually known about this for some time, but since I didn't have a= good=0A= solution...=0A= _______________________________________________=0A= freebsd-net@freebsd.org mailing list=0A= https://lists.freebsd.org/mailman/listinfo/freebsd-net=0A= To unsubscribe, send any mail to "freebsd-net-unsubscribe@freebsd.org"=0A=