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  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, 1 Jul 2010 15:50:38 +0300
From:	"Michael S. Tsirkin" <>
To:	Peter Zijlstra <>
Cc:	Ingo Molnar <>, Sridhar Samudrala <>,
	Tejun Heo <>, Oleg Nesterov <>,
	netdev <>,
	lkml <>,
	"" <>,
	Andrew Morton <>,
	Dmitri Vorobiev <>,
	Jiri Kosina <>,
	Thomas Gleixner <>,
	Andi Kleen <>
Subject: Re: [PATCH repost] sched: export sched_set/getaffinity to modules

On Thu, Jul 01, 2010 at 02:32:43PM +0200, Peter Zijlstra wrote:
> On Thu, 2010-07-01 at 14:55 +0300, Michael S. Tsirkin wrote:
> > >  - why can't it set the kernel thread's affinity too?
> > 
> > It can. However: the threads are started internally by the driver
> > when qemu does an ioctl.  What we want to do is give it a sensible
> > default affinity. management tool can later tweak it if it wants to.
> So have that ioctl return the tid of that new fancy thread and then set
> its affinity, stuff it in cgroup, whatever you fancy.
> > >  - what happens if someone changes the tasks' affinity?
> > 
> > We would normally create a cgroup including all internal
> > tasks, making it easy to find and change affinity for
> > them all if necessary. 
> And to stuff them in a cgroup you also need the tid, at which point it
> might as well set the affinity from userspace, right?

We also put it in a cgroup transparently. I think that it's actually
important to do it on thread creation: if we don't, malicious userspace
can create large amount of work exceeding the cgroup limits.

And the same applies so the affinity, right? If the qemu process
is limited to a set of CPUs, isn't it important to make
the kernel thread that does work our behalf limited to the same
set of CPUs?

To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to
More majordomo info at

Powered by blists - more mailing lists