tree f2e1340e3c19eda7c28b1c73c1f9f39c13e381a1
parent 647bd61a5f3a51a38c670f91af9d861ad66149a3
author Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com> 1184567987 -0700
committer Linus Torvalds <torvalds@woody.linux-foundation.org> 1184601941 -0700

Fix stop_machine_run problem with naughty real time process

stop_machine_run() does its work on "kstopmachine" thread having max
priority.  However that thread get such priority after woken up.
Therefore, in the following case ...

  - "kstopmachine" try to run on CPU1

  - There is a real time process which doesn't relinquish CPU time
    voluntary on CPU1

...  "kstopmachine" can't start to run and the CPU on which
    stop_machine_run() is runing hangs up.  To fix this problem, call
    sched_setscheduler() before waking up that thread.

Signed-off-by: Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Ashok Raj <ashok.raj@intel.com>
Cc: Gautham R Shenoy <ego@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>