Messages in this thread | | | From | Linus Torvalds <> | Date | Tue, 26 Apr 2011 10:18:22 -0700 | Subject | Re: 2.6.39-rc4+: Kernel leaking memory during FS scanning, regression? |
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On Tue, Apr 26, 2011 at 10:09 AM, Bruno Prémont <bonbons@linux-vserver.org> wrote: > > Just in case, /proc/$(pidof rcu_kthread)/status shows ~20k voluntary > context switches and exactly one non-voluntary one. > > In addition when rcu_kthread has stopped doing its work > `swapoff $(swapdevice)` seems to block forever (at least normal shutdown > blocks on disabling swap device). > If I get to do it when I get back home I will manually try to swapoff > and take process traces with sysrq-t.
That "exactly one non-voluntary one" sounds like the smoking gun.
Normally SCHED_FIFO runs until it voluntarily gives up the CPU. That's kind of the point of SCHED_FIFO. Involuntary context switches happen when some higher-priority SCHED_FIFO process becomes runnable (irq handlers? You _do_ have CONFIG_IRQ_FORCED_THREADING=y in your config too), and maybe there is a bug in the runqueue handling for that case.
Ingo, do you have any tests for SCHED_FIFO scheduling? Particularly with UP and voluntary preempt?
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