From: Trond Myklebust <trondmy@primarydata.com>
To: "bfields@fieldses.org" <bfields@fieldses.org>,
"efault@gmx.de" <efault@gmx.de>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-nfs@vger.kernel.org" <linux-nfs@vger.kernel.org>,
"jlayton@kernel.org" <jlayton@kernel.org>
Subject: Re: NFS: 82ms wakeup latency 4.14-rc4
Date: Mon, 18 Dec 2017 17:24:29 +0000 [thread overview]
Message-ID: <1513617866.4581.6.camel@primarydata.com> (raw)
In-Reply-To: <1513616405.7113.18.camel@gmx.de>
On Mon, 2017-12-18 at 18:00 +0100, Mike Galbraith wrote:
> On Mon, 2017-12-18 at 11:35 -0500, J. Bruce Fields wrote:
> >
> > Like I say, I don't really understand the issues here, so it's more
> > a
> > question than an objection.... (I don't know any reason a
> > cond_resched() would be bad there.)
>
> Think of it this way: what all can be queued up behind that kworker
> that is hogging CPU for huge swaths of time? It's not only userspace
> that suffers.
>
Any cond_sched() belongs in the loop in nfs_commit_release_pages()
(where it can be mitigated) rather than in a function whose purpose is
to free memory. There is no reason to call it from the writeback or
readpages code.
--
Trond Myklebust
Linux NFS client maintainer, PrimaryData
trond.myklebust@primarydata.com
next prev parent reply other threads:[~2017-12-18 17:24 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-18 15:17 NFS: 82ms wakeup latency 4.14-rc4 Mike Galbraith
2017-12-18 15:31 ` Mike Galbraith
2017-12-18 16:35 ` J. Bruce Fields
2017-12-18 16:48 ` Mike Galbraith
2017-12-18 17:00 ` Mike Galbraith
2017-12-18 17:17 ` Mike Galbraith
2017-12-18 17:27 ` J. Bruce Fields
2017-12-18 17:47 ` Mike Galbraith
2017-12-18 18:34 ` Mike Galbraith
2017-12-18 17:24 ` Trond Myklebust [this message]
2017-12-18 17:26 ` Mike Galbraith
2018-01-02 20:29 ` [patch] fs/nfs: Add a resched point to nfs_commit_release_pages() Mike Galbraith
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