Re: [PATCH] numa: Add missing \n to error message

[Laurent Vivier <laurent@vivier.eu>]

Le 06/11/2019 à 15:12, Greg Kurz a écrit :
> On Wed, 6 Nov 2019 14:01:01 +0100
> Laurent Vivier <laurent@vivier.eu> wrote:
> 
>> Le 06/11/2019 à 13:46, Greg Kurz a écrit :
>>> If memory allocation fails when using -mem-path, QEMU is supposed to print
>>> out a message to indicate that fallback to anonymous RAM is deprecated. This
>>> is done with error_printf() which does output buffering. As a consequence,
>>> the message is only printed at the next flush, eg. when quiting QEMU, and
>>> it also lacks a trailing newline:
>>>
>>> qemu-system-ppc64: unable to map backing store for guest RAM: Cannot allocate memory
>>> qemu-system-ppc64: warning: falling back to regular RAM allocation
>>> QEMU 4.1.50 monitor - type 'help' for more information
>>> (qemu) q
>>> This is deprecated. Make sure that -mem-path  specified path has sufficient resources to allocate -m specified RAM amountgreg@boss02:~/Work/qemu/qemu-spapr$
>>>
>>> Add the missing \n to fix both issues.
>>>
>>> Fixes: cb79224b7e4b "deprecate -mem-path fallback to anonymous RAM"
>>> Signed-off-by: Greg Kurz <groug@kaod.org>
>>> ---
>>>  hw/core/numa.c |    2 +-
>>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/hw/core/numa.c b/hw/core/numa.c
>>> index 038c96d4abc6..e3332a984f7c 100644
>>> --- a/hw/core/numa.c
>>> +++ b/hw/core/numa.c
>>> @@ -503,7 +503,7 @@ static void allocate_system_memory_nonnuma(MemoryRegion *mr, Object *owner,
>>>              warn_report("falling back to regular RAM allocation");
>>>              error_printf("This is deprecated. Make sure that -mem-path "
>>>                           " specified path has sufficient resources to allocate"
>>> -                         " -m specified RAM amount");
>>> +                         " -m specified RAM amount\n");
>>>              /* Legacy behavior: if allocation failed, fall back to
>>>               * regular RAM allocation.
>>>               */
>>>
>>>
>>
>> Why is this an error_printf() and not an error_report()?
>>
> 
> Because CODING_STYLE suggests to do so I guess:
> 
> Reporting errors to the human user
> ----------------------------------
> 
> Do not use printf(), fprintf() or monitor_printf().  Instead, use
> error_report() or error_vreport() from error-report.h.  This ensures the
> error is reported in the right place (current monitor or stderr), and in
> a uniform format.
> 
> Use error_printf() & friends to print additional information. <===
> 
> error_report() prints the current location.  In certain common cases
> like command line parsing, the current location is tracked
> automatically.  To manipulate it manually, use the loc_``*``() from
> error-report.h.

So I guess it's to not report the current location and the binary name .

Reviewed-by: Laurent Vivier <laurent@vivier.eu>