Re: [kvm-unit-tests PATCH 2/4] s390x: smp: Only use smp_cpu_setup once

[Janosch Frank <frankja@linux.ibm.com>]

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On 1/14/20 5:45 PM, Thomas Huth wrote:
> On 14/01/2020 16.30, Janosch Frank wrote:
>> Let's stop and start instead of using setup to run a function on a
>> cpu.
>>
>> Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
>> ---
>>  s390x/smp.c | 19 ++++++++++++-------
>>  1 file changed, 12 insertions(+), 7 deletions(-)
>>
>> diff --git a/s390x/smp.c b/s390x/smp.c
>> index 4dee43e..767d167 100644
>> --- a/s390x/smp.c
>> +++ b/s390x/smp.c
>> @@ -47,7 +47,7 @@ static void test_start(void)
>>  	psw.mask = extract_psw_mask();
>>  	psw.addr = (unsigned long)test_func;
>>  
>> -	smp_cpu_setup(1, psw);
>> +	smp_cpu_start(1, psw);
>>  	wait_for_flag();
>>  	report(1, "start");
>>  }
>> @@ -131,9 +131,8 @@ static void test_ecall(void)
>>  
>>  	report_prefix_push("ecall");
>>  	testflag = 0;
>> -	smp_cpu_destroy(1);
>>  
>> -	smp_cpu_setup(1, psw);
>> +	smp_cpu_start(1, psw);
>>  	wait_for_flag();
>>  	testflag = 0;
>>  	sigp(1, SIGP_EXTERNAL_CALL, 0, NULL);
>> @@ -166,9 +165,8 @@ static void test_emcall(void)
>>  
>>  	report_prefix_push("emcall");
>>  	testflag = 0;
>> -	smp_cpu_destroy(1);
>>  
>> -	smp_cpu_setup(1, psw);
>> +	smp_cpu_start(1, psw);
>>  	wait_for_flag();
>>  	testflag = 0;
>>  	sigp(1, SIGP_EMERGENCY_SIGNAL, 0, NULL);
>> @@ -186,7 +184,7 @@ static void test_reset_initial(void)
>>  	psw.addr = (unsigned long)test_func;
>>  
>>  	report_prefix_push("reset initial");
>> -	smp_cpu_setup(1, psw);
>> +	smp_cpu_start(1, psw);
>>  
>>  	sigp_retry(1, SIGP_INITIAL_CPU_RESET, 0, NULL);
>>  	sigp(1, SIGP_STORE_STATUS_AT_ADDRESS, (uintptr_t)status, NULL);
>> @@ -217,7 +215,7 @@ static void test_reset(void)
>>  	psw.addr = (unsigned long)test_func;
>>  
>>  	report_prefix_push("cpu reset");
>> -	smp_cpu_setup(1, psw);
>> +	smp_cpu_start(1, psw);
> 
> I think this also fixes a memory leak in case the code did not call
> smp_cpu_destroy() inbetween (since smp_cpu_setup() allocates new memory
> for the low-core). So as far as I can see, this is a good idea:

Well, if the cpu is active, we should just return in the setup function.
But I have another patch in the queue which cleans up lowcore allocation.

> 
> Reviewed-by: Thomas Huth <thuth@redhat.com>
> 



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