On 10.03.23 11:43, Linux regression tracking (Thorsten Leemhuis) wrote: > [CCing the regression list, as it should be in the loop for regressions: > https://docs.kernel.org/admin-guide/reporting-regressions.html] > > [also adding the author of the culprit (Trond) and the second NFS client > maintainer (Anna) to the list of recipients] Trond, sorry to bother you, but do you still have this regression report on your radar? It looks a bit like it fall through the cracks, as I don't see any reply since it was posted nearly two weeks ago. Or did some progress to address this happen and I just missed it? Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat) -- Everything you wanna know about Linux kernel regression tracking: https://linux-regtracking.leemhuis.info/about/#tldr If I did something stupid, please tell me, as explained on that page. #regzbot poke > [TLDR: I'm adding this report to the list of tracked Linux kernel > regressions; the text you find below is based on a few templates > paragraphs you might have encountered already in similar form. > See link in footer if these mails annoy you.] > > On 07.03.23 18:38, Daire Byrne wrote: >> I noticed a change in behaviour in the v6.2.x client versus v6.1.12 (and below). >> >> We have some servers that mount Netapps from different locations many >> milliseconds away, and these contain apps and libs that get added to >> the LD_LIBRARY_PATH and PATH on remote login. >> >> I then noticed that when I ssh'd into a remote server that had these >> mounts and the shell was starting, the first login was normal and I >> observed an expected flurry of lookups,getattrs and access calls for a >> grand total of only ~120 packets to the Netapp. >> >> But when I disconnect and reconnect (ssh), now I see a flood of access >> calls to the netapp for a handful of repeating filehandles which look >> something like: >> >> 2700 85.942563180 10.23.112.10 → 10.23.21.11 NFS 254 V3 ACCESS Call, >> FH: 0x7f36addc, [Check: RD LU MD XT DL] >> 2701 85.999838796 10.23.21.11 → 10.23.112.10 NFS 190 V3 ACCESS Reply >> (Call In 2700), [Allowed: RD LU MD XT DL] >> 2702 85.999970825 10.23.112.10 → 10.23.21.11 NFS 254 V3 ACCESS Call, >> FH: 0x7f36addc, [Check: RD LU MD XT DL] >> 2703 86.055340946 10.23.21.11 → 10.23.112.10 NFS 190 V3 ACCESS Reply >> (Call In 2702), [Allowed: RD LU MD XT DL] >> 2704 86.056865308 10.23.112.10 → 10.23.21.11 NFS 254 V3 ACCESS Call, >> FH: 0x7f36addc, [Check: RD LU MD XT DL] >> 2705 86.112233415 10.23.21.11 → 10.23.112.10 NFS 190 V3 ACCESS Reply >> (Call In 2704), [Allowed: RD LU MD XT DL] >> >> This time we total 5000+ packets for this login which becomes very >> noticeable when the Netapp is 50ms away. >> >> I didn't understand why the first login was fine but the second goes >> into this repeating access pattern. I set actimeo=3600 (long) but it >> does not seem to affect it. >> >> I do not see this prior to v6.2 where repeated logins are equally fast >> and we don't see the repeating access calls. >> >> So a bit of digging through the v6.2 changes and this looked like the >> relevant change: >> >> commit 0eb43812c027 ("NFS: Clear the file access cache upon login”) >> [PATCH] NFS: Judge the file access cache's timestamp in rcu path? >> >> I reverted those and got the prior (v6.1) performance. >> >> What constitutes a login exactly? I also have services like "sysstat" >> or pcp that cause a systemd-logind to trigger regularly on our >> machines.... does that count and invalidate the cache? >> >> Do the repeated access calls on the same handful of filehandles make >> sense? Even prior to those patches (or v6.1) there are only a couple >> of ACCESS calls to the Netapp on login. >> >> We are a bit unique in that we run quite a few WAN high latency NFS >> workflows so are happy to trade long lived caches (e.g. actimeo and >> even nocto on occasion) for lower ops at the expense of total >> correctness. > > Thanks for the report. To be sure the issue doesn't fall through the > cracks unnoticed, I'm adding it to regzbot, the Linux kernel regression > tracking bot: > > #regzbot ^introduced 0eb43812c027 > #regzbot title nfs: flood of access on second log-in (first is fine) > #regzbot ignore-activity > > This isn't a regression? This issue or a fix for it are already > discussed somewhere else? It was fixed already? You want to clarify when > the regression started to happen? Or point out I got the title or > something else totally wrong? Then just reply and tell me -- ideally > while also telling regzbot about it, as explained by the page listed in > the footer of this mail. > > Developers: When fixing the issue, remember to add 'Link:' tags pointing > to the report (the parent of this mail). See page linked in footer for > details. > > Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat) > -- > Everything you wanna know about Linux kernel regression tracking: > https://linux-regtracking.leemhuis.info/about/#tldr > That page also explains what to do if mails like this annoy you.
