lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <87ft55nd6n.fsf@notabene.neil.brown.name>
Date:   Fri, 20 Nov 2020 10:23:44 +1100
From:   NeilBrown <neilb@...e.de>
To:     "tj@...nel.org" <tj@...nel.org>,
        Trond Myklebust <trondmy@...merspace.com>
Cc:     "jiangshanlai@...il.com" <jiangshanlai@...il.com>,
        "mhocko@...e.com" <mhocko@...e.com>,
        "peterz@...radead.org" <peterz@...radead.org>,
        "juri.lelli@...hat.com" <juri.lelli@...hat.com>,
        "mingo@...hat.com" <mingo@...hat.com>,
        "vincent.guittot@...aro.org" <vincent.guittot@...aro.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH rfc] workqueue: honour cond_resched() more effectively.

On Mon, Nov 09 2020, tj@...nel.org wrote:

>                                                    Given that nothing on
> these types of workqueues can be latency sensitive

This caught my eye and it seems worth drilling in to.  There is no
mention of "latency" in workqueue.rst or workqueue.h.  But you seem to
be saying there is an undocumented assumption that latency-sensitive
work items much not be scheduled on CM-workqueues.
Is that correct?

NFS writes are latency sensitive to a degree as increased latency per
request will hurt overall throughput.  Does this mean that handling
write-completion in a CM-wq is a poor choice?
Would it be better to us WQ_HIGHPRI??  Is there any rule-of-thumb that
can be used to determine when WQ_HIGHPRI is appropriate?

Thanks,
NeilBrown

Download attachment "signature.asc" of type "application/pgp-signature" (854 bytes)

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ