On 21.04.2010, at 12:04, Jun Koi wrote:
> On Tue, Apr 20, 2010 at 8:44 PM, Alexander Graf <ag...@suse.de> wrote:
>>
>> On 20.04.2010, at 13:38, Jan Kiszka wrote:
>>
>>> Alexander Graf wrote:
>>>> On 20.04.2010, at 09:18, Jan Kiszka wrote:
>>>>
>>>>> Jun Koi wrote:
>>>>>> Thank you for the explanation of this code.
>>>>>>
>>>>>> Qemu has a command named singlestep, which reduces the translated code
>>>>>> block to be only one instruction.
>>>>>> This new patch flushes TBs both when singlestep is on and off.
>>>>>>
>>>>>> Signed-off-by: Jun Koi <junkoi2...@gmail.com>
>>>>>>
>>>>>>
>>>>>> diff --git a/monitor.c b/monitor.c
>>>>>> index 5659991..2b2005b 100644
>>>>>> --- a/monitor.c
>>>>>> +++ b/monitor.c
>>>>>> @@ -1187,13 +1187,26 @@ static void do_log(Monitor *mon, const QDict
>>>>>> *qdict)
>>>>>> cpu_set_log(mask);
>>>>>> }
>>>>>>
>>>>>> +/* flush all the TBs to force new code generation */
>>>>>> +static void flush_all_tb(void)
>>>>>> +{
>>>>>> + CPUState *env;
>>>>>> +
>>>>>> + for (env = first_cpu; env != NULL; env = env->next_cpu) {
>>>>>> + tb_flush(env);
>>>>>> + }
>>>>>> +}
>>>>>> +
>>>>> The smaller your patch are, the more people pick on it. :)
>>>>>
>>>>> I was about to suggest moving this close to tb_flush, but then I
>>>>> realized that the env argument of that service is misleading. In fact,
>>>>> it already flushes the one and only translation buffer pool.
>>>>>
>>>>>> static void do_singlestep(Monitor *mon, const QDict *qdict)
>>>>>> {
>>>>>> const char *option = qdict_get_try_str(qdict, "option");
>>>>>> +
>>>>>> if (!option || !strcmp(option, "on")) {
>>>>>> singlestep = 1;
>>>>>> + flush_all_tb();
>>>>>> } else if (!strcmp(option, "off")) {
>>>>>> singlestep = 0;
>>>>>> + flush_all_tb();
>>>>>> } else {
>>>>>> monitor_printf(mon, "unexpected option %s\n", option);
>>>>>> }
>>>>>>
>>>>> Let's just pass mon->mon_cpu to tb_flush and skip the redundant loop.
>>>>
>>>> That doesn't help, no? singlestep is a global variable. Flushing only the
>>>> current vcpu would still not affect the others, while the singlestep
>>>> switch would.
>>>
>>> tb_flush uses env only to dump some state when a problem occurred.
>>>
>>>>
>>>> According to your above comment the cache is global, but I don't think we
>>>> should rely on that.
>>>
>>> It might make sense to define some tb_flush_all() as tb_flush(first_cpu)
>>> for now to establish the infrastructure. Then we are prepared for the
>>> day the tb_flush implementation may change.
>>
>> Right. But then the call to tb_flush_all here is still correct.
>
> So what is the final solution do you want?
>
> I still think that having flush_all_tb() like in the last patch is good
> enough.
I agree. And I like the patch as is.
Acked-by: Alexander Graf <ag...@suse.de>
Alex
