[lkml]   [2013]   [Nov]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [PATCH] kmod: Run usermodehelpers only on cpus allowed for kthreadd V2
On Thu, 7 Nov 2013, Frederic Weisbecker wrote:

> usermodehelper works are created via workqueues, right? And workqueues are an issue as
> well for those who want CPU isolation.

AFAICT usermodehelper can be called from a variety of contexts.

> So this looks like a more general problem than just call_usermodehelper.

Well the code explicitly sets the the affinity mask to all cpus which
creates a problem for low latency processors. It does not inherit the
affinity from any calling process.

> Last time I checked, it seemed to me that this is an unbound workqueue? If so can't we tune
> the affinity of this workqueue? If not perhaps that's something we want to solve and which
> could be useful for all the users who don't want their CPU to be disturbed.

There are various contexts from which usermodehelper can be called.
Drivers use it etc.

 \ /
  Last update: 2013-11-08 18:01    [W:0.082 / U:0.060 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site