On Wed, May 19, 2010 at 12:53:26PM -0400, Masami Hiramatsu wrote:
> Introduce text_poke_smp_batch(). This function modifies several
> text areas with one stop_machine() on SMPr. Because calling
> stop_machine() is heavy task, it is better to aggregate text_poke
> requests.
>
> Signed-off-by: Masami Hiramatsu <[email protected]>
> Cc: Ananth N Mavinakayanahalli <[email protected]>
> Cc: Ingo Molnar <[email protected]>
> Cc: Jim Keniston <[email protected]>
> Cc: Jason Baron <[email protected]>
> Cc: Mathieu Desnoyers <[email protected]>
<snip>
> +/**
> + * text_poke_smp_batch - Update instructions on a live kernel on SMP
> + * @params: an array of text_poke parameters
> + * @n: the number of elements in params.
> + *
> + * Modify multi-byte instruction by using stop_machine() on SMP. Since the
> + * stop_machine() is heavy task, it is better to aggregate text_poke requests
> + * and do it once if possible.
> + *
> + * Note: Must be called under get_online_cpus() and text_mutex.
> + */
> +void __kprobes text_poke_smp_batch(struct text_poke_param *params, int n)
> +{
> + struct text_poke_params tpp = {.params = params, .nparams = n};
> +
> + atomic_set(&stop_machine_first, 1);
> + wrote_text = 0;
> + stop_machine(stop_machine_text_poke, (void *)&tpp, NULL);
> +}
Looks good. But wouldn't it be even better to get stop_machine()
be able to support batches itself?
We could have stop_machine_queue() and stop_machine_flush(),
stop_machine() would be a shortcut for both, to execute single jobs,
may be that could simplify some code here and there.
Frederic Weisbecker wrote:
> On Wed, May 19, 2010 at 12:53:26PM -0400, Masami Hiramatsu wrote:
>> Introduce text_poke_smp_batch(). This function modifies several
>> text areas with one stop_machine() on SMPr. Because calling
>> stop_machine() is heavy task, it is better to aggregate text_poke
>> requests.
>>
>> Signed-off-by: Masami Hiramatsu <[email protected]>
>> Cc: Ananth N Mavinakayanahalli <[email protected]>
>> Cc: Ingo Molnar <[email protected]>
>> Cc: Jim Keniston <[email protected]>
>> Cc: Jason Baron <[email protected]>
>> Cc: Mathieu Desnoyers <[email protected]>
> <snip>
>> +/**
>> + * text_poke_smp_batch - Update instructions on a live kernel on SMP
>> + * @params: an array of text_poke parameters
>> + * @n: the number of elements in params.
>> + *
>> + * Modify multi-byte instruction by using stop_machine() on SMP. Since the
>> + * stop_machine() is heavy task, it is better to aggregate text_poke requests
>> + * and do it once if possible.
>> + *
>> + * Note: Must be called under get_online_cpus() and text_mutex.
>> + */
>> +void __kprobes text_poke_smp_batch(struct text_poke_param *params, int n)
>> +{
>> + struct text_poke_params tpp = {.params = params, .nparams = n};
>> +
>> + atomic_set(&stop_machine_first, 1);
>> + wrote_text = 0;
>> + stop_machine(stop_machine_text_poke, (void *)&tpp, NULL);
>> +}
>
>
> Looks good. But wouldn't it be even better to get stop_machine()
> be able to support batches itself?
>
> We could have stop_machine_queue() and stop_machine_flush(),
> stop_machine() would be a shortcut for both, to execute single jobs,
> may be that could simplify some code here and there.
>
Ah, that's nice too :) But I don't know other people who need
that interfaces. Would you know there are any other potential users?
Thank you,