Re: [PATCH -tip v4 3/3] kprobes: Support delayed unoptimization

[Masami Hiramatsu]

(2010/11/26 16:26), Ingo Molnar wrote:
> * Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx> wrote:
> 
>> Unoptimization occurs when a probe is unregistered or disabled, and
>> is heavy because it recovers instructions by using stop_machine().
>> This patch delays unoptimization operations and unoptimize several
>> probes at once by using text_poke_smp_batch().
>> This can avoid unexpected system slowdown coming from stop_machine().
>>
>> Changes in v2:
>> - Use dynamic allocated buffers and params.
>>
>> Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
>> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
>> Cc: Ingo Molnar <mingo@xxxxxxxxxx>
>> Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
>> Cc: x86@xxxxxxxxxx
>> Cc: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx>
>> Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
>> Cc: Ananth N Mavinakayanahalli <ananth@xxxxxxxxxx>
>> Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
>> Cc: linux-kernel@xxxxxxxxxxxxxxx
>> Cc: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
>> Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
>> ---
>>
>>  arch/x86/include/asm/kprobes.h |    4 
>>  arch/x86/kernel/kprobes.c      |   45 ++++
>>  include/linux/kprobes.h        |    2 
>>  kernel/kprobes.c               |  434 +++++++++++++++++++++++++++-------------
>>  4 files changed, 344 insertions(+), 141 deletions(-)
> 
> Hm, this is a scary big patch with non-trivial effects - it should be broken up as 
> much as possible, into successive, bisectable steps. The end result looks mostly 
> fine - it's just this one huge step of a patch that is dangerous.

Agreed, then I'll break it down to several patches.
Thank you for your comment! :)

> 
> Thanks,
> 
> 	Ingo


-- 
Masami HIRAMATSU
2nd Dept. Linux Technology Center
Hitachi, Ltd., Systems Development Laboratory
E-mail: masami.hiramatsu.pt@xxxxxxxxxxx
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