Kernel threads inherit CPU affinity from random sibling

[Eugene Grosbein]

28.01.2012 20:22, Attilio Rao пишет:

> 2012/1/28 Ryan Stone <rysto32 at gmail.com>:
>> On Fri, Jan 27, 2012 at 10:41 PM, Attilio Rao <attilio at freebsd.org> wrote:
>>> I think what you found out is very sensitive.
>>> However, the patch is not correct as you cannot call
>>> cpuset_setthread() with thread_lock held.
>>
>> Whoops!  I actually discovered that for myself and had already fixed
>> it, but apparently I included an old version of the patch in the
>> email.
>>
>>> Hence this is my fix:
>>> http://www.freebsd.org/~attilio/cpuset_root.patch
>>
>> Oh, I do like this better.  I tried something similar myself but
>> abandoned it because I misread how sched_affinity() was implemented by
>> 4BSD(I had gotten the impression that once TSF_AFFINITY is set it
>> could never be cleared).
> 
> Do you have a pathological test-case for it? Are you going to test the patch?

I have the pathological test-case for it:
http://www.freebsd.org/cgi/query-pr.cgi?pr=165444

Eugene Grosbein