Re: [Xen-devel] [PATCH 5/5] tools/libxc: allow controlling the max C-state sub-state

["Jan Beulich" <JBeulich@suse.com>]

>>> On 10.06.19 at 18:54, <andrew.cooper3@citrix.com> wrote:
> On 23/05/2019 13:19, Jan Beulich wrote:
>> From: Ross Lagerwall <ross.lagerwall@citrix.com>
>>
>> Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
>>
>> Make handling in do_pm_op() more homogeneous: Before interpreting
>> op->cpuid as such, handle all operations not acting on a particular
>> CPU. Also expose the setting via xenpm.
>>
>> Signed-off-by: Jan Beulich <jbeulich@suse.com>
>>
>> --- a/tools/libxc/xc_pm.c
>> +++ b/tools/libxc/xc_pm.c
>> @@ -379,7 +379,7 @@ int xc_get_cpuidle_max_cstate(xc_interfa
>>      }
>>      sysctl.cmd = XEN_SYSCTL_pm_op;
>>      sysctl.u.pm_op.cmd = XEN_SYSCTL_pm_op_get_max_cstate;
>> -    sysctl.u.pm_op.cpuid = 0;
>> +    sysctl.u.pm_op.cpuid = type;
> 
> What is type, and why it is being put into a field called cpuid?

Since this isn't code I wrote I'm inclined to say "see the comment
in the public header". Given the pretty special case this is about
I'm not really fancying introducing new structures / fields in
sysctl.h, but judging from your reply you presumably want me to.

>> --- a/tools/misc/xenpm.c
>> +++ b/tools/misc/xenpm.c
>> @@ -1120,13 +1128,17 @@ void get_vcpu_migration_delay_func(int a
>>  
>>  void set_max_cstate_func(int argc, char *argv[])
>>  {
>> -    int value;
>> +    int value, subval = XEN_SYSCTL_CX_UNLIMITED;
>>      char buf[12];
>>  
>> -    if ( argc != 1 ||
>> +    if ( argc < 1 || argc > 2 ||
>>           (sscanf(argv[0], "%d", &value) == 1
>>            ? value < 0
>> -          : (value = XEN_SYSCTL_CX_UNLIMITED, strcmp(argv[0], "unlimited"))) )
>> +          : (value = XEN_SYSCTL_CX_UNLIMITED, strcmp(argv[0], "unlimited"))) ||
>> +         (argc == 2 &&
>> +          (sscanf(argv[1], "%d", &subval) == 1
>> +           ? subval < 0
>> +           : (subval = XEN_SYSCTL_CX_UNLIMITED, strcmp(argv[1], "unlimited")))) )
> 
> Usage update?

Well, yes. That's what I get for picking up other folks' patches.

Jan



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