linux-kernel - Re: [PATCH v1 3/3] drivers/tty: increase priority for tty_buffer

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]

Date:   Thu, 10 Jan 2019 17:30:30 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     Oleksij Rempel <o.rempel@...gutronix.de>
Cc:     Linus Torvalds <torvalds@...ux-foundation.org>,
        Jiri Slaby <jslaby@...e.com>,
        Pengutronix Kernel Team <kernel@...gutronix.de>,
        lkml <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v1 3/3] drivers/tty: increase priority for
 tty_buffer_worker

On Thu, Jan 10, 2019 at 04:19:53PM +0100, Oleksij Rempel wrote:
> > My gut feel is that if somebody still cares deeply about serial line
> > latency, they should look at trying to see if they can do some of the
> > work directly without the bounce to the workqueue. We use workqueues
> > for a reason, but it's possible that some of it could be avoided at
> > least in special cases... And yours sounds like a special case.
> 
> It is for industrial low latency RS-422 based application. The loopback
> test is just easy way to test/reproduce it without additional hardware.
> 
> What is good, mainlineable way to implement it? 

What is the real problem your systems are having?  Are they serial-port
limited?  Is latency a big issue?  Trying to tune for a fake workload
isn't the best way to solve anything :)

thanks,
greg k-h