Re: [PATCH tracing/kprobes] kprobes: Disable booster when CONFIG_PREEMPT=y
From: Masami Hiramatsu
Date: Fri Jan 29 2010 - 09:50:23 EST
Ingo Molnar wrote:
> * Masami Hiramatsu <mhiramat@xxxxxxxxxx> wrote:
>> Disable kprobe booster when CONFIG_PREEMPT=y, because it can't ensure that
>> all kernel threads preempted on kprobe's boosted slot run out from the slot
>> even using freeze_processes().
> hm, this really sucks as it makes preemptible kernels perform worse. Is there
> no better solution?
>> The booster on preemptive kernel will be resumed if synchronize_tasks() or
>> something like that is introduced.
> such as this one?
Yes, I think this synchronize_tasks(), which just (sleeping) wait until
all currently preempted tasks are wake up and scheduled, can ensure safety.
Hitachi Computer Products (America), Inc.
Software Solutions Division
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