netdev - Re: [PATCH net-next 1/9] net/mlx4_core: Enforce irq affinity changes immediatly

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: <1400358787.2647.65.camel@deadeye.wl.decadent.org.uk>
Date:	Sat, 17 May 2014 21:33:07 +0100
From:	Ben Hutchings <ben@...adent.org.uk>
To:	Amir Vadai <amirv@...lanox.com>
Cc:	"David S. Miller" <davem@...emloft.net>, netdev@...r.kernel.org,
	Yevgeny Petrilin <yevgenyp@...lanox.com>,
	Or Gerlitz <ogerlitz@...lanox.com>,
	Yuval Atias <yuvala@...lanox.com>
Subject: Re: [PATCH net-next 1/9] net/mlx4_core: Enforce irq affinity
 changes immediatly

On Mon, 2014-05-12 at 10:43 +0300, Amir Vadai wrote:
> From: Yuval Atias <yuvala@...lanox.com>
> 
> During heavy traffic, napi is constatntly polling the complition queue
> and no interrupt is fired. Because of that, changes to irq affinity are
> ignored until traffic is stopped and resumed.
> 
> By registering to the irq notifier mechanism, and forcing interrupt when
> affinity is changed, irq affinity changes will be immediatly enforced.
[...]

This somewhat breaks ARFS in your driver, as that depends on IRQ
affinity notification.

It is also not safe to put an IRQ affinity notification function in a
module currently, as the work item for notification doesn't carry a
module reference and could be called after the module is removed.

Ben.

-- 
Ben Hutchings
I'm not a reverse psychological virus.  Please don't copy me into your sig.

Download attachment "signature.asc" of type "application/pgp-signature" (829 bytes)