Re: [Xen-devel] [PATCH v2 4/5] xenstore: make memory report available via XS_CONTROL

[Juergen Gross <jgross@xxxxxxxx>]

On 22/02/17 13:47, Wei Liu wrote:
> On Wed, Feb 22, 2017 at 01:43:27PM +0100, Juergen Gross wrote:
>> On 22/02/17 13:36, Wei Liu wrote:
>>> On Tue, Feb 21, 2017 at 04:07:36PM +0100, Juergen Gross wrote:
>>>> Add a XS_CONTROL command to xenstored for doing a talloc report to a
>>>> file. Right now this is supported by specifying a command line option
>>>> when starting xenstored and sending a signal to the daemon to trigger
>>>> the report.
>>>>
>>>> To dump the report to the standard log file call:
>>>>
>>>> xenstore-control memreport
>>>>
>>>> To dump the report to a new file call:
>>>>
>>>> xenstore-control memreport <file>
>>>>
>>>> Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
>>>> ---
>>>>  tools/xenstore/xenstored_control.c | 36 
>>>> ++++++++++++++++++++++++++++++++++++
>>>>  tools/xenstore/xenstored_core.c    |  2 +-
>>>>  tools/xenstore/xenstored_core.h    |  1 +
>>>>  3 files changed, 38 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/tools/xenstore/xenstored_control.c 
>>>> b/tools/xenstore/xenstored_control.c
>>>> index c3587ad..b4ec6ce 100644
>>>> --- a/tools/xenstore/xenstored_control.c
>>>> +++ b/tools/xenstore/xenstored_control.c
>>>> @@ -76,6 +76,41 @@ static int do_control_logfile(void *ctx, struct 
>>>> connection *conn,
>>>>    return 0;
>>>>  }
>>>>  
>>>> +static int do_control_memreport(void *ctx, struct connection *conn,
>>>> +                          char **vec, int num)
>>>> +{
>>>> +  FILE *fp;
>>>> +  int fd;
>>>> +
>>>> +  if (num > 1)
>>>> +          return EINVAL;
>>>> +
>>>> +  if (num == 0) {
>>>> +          if (tracefd < 0) {
>>>> +                  if (!tracefile)
>>>> +                          return EBADF;
>>>> +                  fp = fopen(tracefile, "a");
>>>> +          } else {
>>>> +                  fd = dup(tracefd);
>>>
>>> Why dup() the fd? Is it because you want to avoid tracefd becomes
>>> invalid under your feet?
>>>
>>
>> I want to be able to fclose() to get rid of the stream resources without
>> closing the log file.
>>
> 
> Oh, right. I missed that aspect. Could you please add a comment for that
> please.

Sure.


Juergen


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