Messages in this thread | | | From | Steve French <> | Date | Tue, 19 Sep 2023 13:23:44 -0500 | Subject | Re: Possible bug report: kernel 6.5.0/6.5.1 high load when CIFS share is mounted (cifsd-cfid-laundromat in"D" state) |
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On Tue, Sep 19, 2023 at 1:07 PM Tom Talpey <tom@talpey.com> wrote: > > On 9/19/2023 9:38 AM, Steve French wrote: > > Minor updates (pointed out by Paulo) to patch. See attached. > > So, was the thread crashing before?? > > + if (cfids == NULL) > + return; > +
Without laundromat initialized cfids can be null - so we need to check if cfids is initialized in a few places (may help in a few corner cases if there is a race in closing laundromat thread at umount but was added to avoid oops at unmount if laundromat not initialized)
> These changes are good, but I'm skeptical they will reduce the load > when the laundromat thread is actually running. All these do is avoid > creating it when not necessary, right?
It does create half as many laundromat threads (we don't need laundromat on connection to IPC$) even for the Windows server target example, but helps more for cases where server doesn't support directory leases.
> > On Tue, Sep 19, 2023 at 8:21 AM Brian Pardy <brian.pardy@gmail.com> wrote: > >> > >> On Tue, Sep 19, 2023 at 1:36 AM Steve French <smfrench@gmail.com> wrote: > >>> > >>> Does the attached patch help in your case? It avoids starting the > >>> laundromat thread for IPC shares (which cuts the number of the threads > >>> in half for many cases) and also avoids starting them if the server > >>> does not support directory leases (e.g. if Samba server instead of > >>> Windows server). > >> > >> Hello, > >> > >> I applied the 0001-smb3-do-not-start-laundromat-thread-when-dir-leases-.patch > >> you provided against the 6.5.3 kernel. > >> > >> I can confirm that it resolves this issue - no laundromat threads are > >> created, and the reported load average is as expected, not falsely > >> high. > >> > >> This appears to fully fix the issue in my case. Thank you very much! > >> > >>> On Mon, Sep 18, 2023 at 10:00 PM Steve French <smfrench@gmail.com> wrote: > >>>> > >>>> Paulo and I were discussing the laundromat thread at the SMB3.1.1 test > >>>> event (at SDC this week) which is now going on - will let you know > >>>> what we find. > >>>> > >>>> One obvious thing is that it probably isn't necessary for cases when > >>>> the server does not support directory leases, but we noticed another > >>>> problem as well. > > > > > >
-- Thanks,
Steve
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