linux-kernel - 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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Message-ID: <CAO+kfxRS8JKympxZGKiP48cTdM+QQjd_4VX=Q5ix02gH7EJdeA@mail.gmail.com>
Date:   Tue, 19 Sep 2023 13:42:44 -0400
From:   Brian Pardy <brian.pardy@...il.com>
To:     Steve French <smfrench@...il.com>
Cc:     Bagas Sanjaya <bagasdotme@...il.com>,
        Linux CIFS <linux-cifs@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Linux Regressions <regressions@...ts.linux.dev>,
        Paulo Alcantara <pc@...guebit.com>,
        ronnie sahlberg <ronniesahlberg@...il.com>,
        Shyam Prasad N <nspmangalore@...il.com>,
        Bharath S M <bharathsm@...rosoft.com>
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)

On Tue, Sep 19, 2023 at 12:39 PM Steve French <smfrench@...il.com> wrote:
>
> Minor updates (pointed out by Paulo) to patch. See attached.

I can't comment on the updates between the two versions of the patch,
but I can confirm that the second patch also works as expected to
resolve this issue on my system.

-Brian


> On Tue, Sep 19, 2023 at 8:21 AM Brian Pardy <brian.pardy@...il.com> wrote:
> >
> > On Tue, Sep 19, 2023 at 1:36 AM Steve French <smfrench@...il.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@...il.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