From: Thomas Gleixner Date: Mon, 6 Jun 2011 18:07:38 +0000 (+0200) Subject: sched/rt: Prevent idle task boosting X-Git-Tag: v3.4-rc1~191^2~14 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1c4dd99bed5f6f70932bf8dacdd54d04a2619778;p=pandora-kernel.git sched/rt: Prevent idle task boosting Idle task boosting is a nono in general. There is one exception, when PREEMPT_RT and NOHZ is active: The idle task calls get_next_timer_interrupt() and holds the timer wheel base->lock on the CPU and another CPU wants to access the timer (probably to cancel it). We can safely ignore the boosting request, as the idle CPU runs this code with interrupts disabled and will complete the lock protected section without being interrupted. So there is no real need to boost. Signed-off-by: Thomas Gleixner Acked-by: Peter Zijlstra Link: http://lkml.kernel.org/n/tip-755rvsosz7sdzot12a3gbha6@git.kernel.org Signed-off-by: Ingo Molnar --- Reading git-diff-tree failed