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From:   "NeilBrown" <neilb@suse.de>
To:     "Chuck Lever III" <chuck.lever@oracle.com>
Cc:     "Jeff Layton" <jlayton@redhat.com>, "Chuck Lever" <cel@kernel.org>,
        "Linux NFS Mailing List" <linux-nfs@vger.kernel.org>,
        "lorenzo@kernel.org" <lorenzo@kernel.org>,
        "Dave Chinner" <david@fromorbit.com>
Subject: Re: [PATCH/RFC] sunrpc: constant-time code to wake idle thread
In-reply-to: <B94C13E5-D84F-4BF7-A559-4E701B0AFA6D@oracle.com>
References: <168842897573.139194.15893960758088950748.stgit@manet.1015granger.net>,
 <168842927591.139194.16920372497489479670.stgit@manet.1015granger.net>,
 <168843152047.8939.5788535164524204707@noble.neil.brown.name>,
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 <168894969894.8939.6993305724636717703@noble.neil.brown.name>,
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 <168902752676.8939.10101566412527206148@noble.neil.brown.name>,
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 <B94C13E5-D84F-4BF7-A559-4E701B0AFA6D@oracle.com>
Date:   Tue, 11 Jul 2023 20:25:52 +1000
Message-id: <168907115231.8939.10978056514501244711@noble.neil.brown.name>
Precedence: bulk

On Tue, 11 Jul 2023, Chuck Lever III wrote:
> 
> > On Jul 10, 2023, at 6:30 PM, Jeff Layton <jlayton@redhat.com> wrote:
> > 
> > On Tue, 2023-07-11 at 08:18 +1000, NeilBrown wrote:
> >> On Tue, 11 Jul 2023, Chuck Lever wrote:
> >>> 
> >>> Actually... Lorenzo reminded me that we need to retain a mechanism
> >>> that can iterate through all the threads in a pool. The xarray
> >>> replaces the "all_threads" list in this regard.
> >>> 
> >> 
> >> For what purpose?
> >> 
> > 
> > He's working on a project to add a rpc status procfile which shows in-
> > flight requests:
> > 
> >    https://bugzilla.linux-nfs.org/show_bug.cgi?id=366
> 
> Essentially, we want a lightweight mechanism for detecting
> unresponsive nfsd threads.
> 

Sounds reasonable - thanks.
Obviously the mechanism for that purpose can be completely separate from
any mechanism for finding idle threads.  And it can easily be re-added
if removed because all other uses disappear.

Thanks,
NeilBrown