Re: [PATCH v3] trace:Add "gfp_t" support in synthetic_events

[Xing Zhengjun <zhengjun.xing@linux.intel.com>]

Hi Steve,

    Could you help to review? Thanks.

On 7/13/2019 12:05 AM, Tom Zanussi wrote:
> Hi Zhengjun,
> 
> On Fri, 2019-07-12 at 09:53 +0800, Zhengjun Xing wrote:
>> Add "gfp_t" support in synthetic_events, then the "gfp_t" type
>> parameter in some functions can be traced.
>>
>> Prints the gfp flags as hex in addition to the human-readable flag
>> string.  Example output:
>>
>>    whoopsie-630 [000] ...1 78.969452: testevent: bar=b20
>> (GFP_ATOMIC|__GFP_ZERO)
>>      rcuc/0-11  [000] ...1 81.097555: testevent: bar=a20 (GFP_ATOMIC)
>>      rcuc/0-11  [000] ...1 81.583123: testevent: bar=a20 (GFP_ATOMIC)
>>
>> Signed-off-by: Tom Zanussi <zanussi@kernel.org>
>> Signed-off-by: Zhengjun Xing <zhengjun.xing@linux.intel.com>
> 
> Looks good to me, thanks!
> 
> Tom
> 
>> ---
>>   kernel/trace/trace_events_hist.c | 19 +++++++++++++++++++
>>   1 file changed, 19 insertions(+)
>>
>> diff --git a/kernel/trace/trace_events_hist.c
>> b/kernel/trace/trace_events_hist.c
>> index ca6b0dff60c5..30f0f32aca62 100644
>> --- a/kernel/trace/trace_events_hist.c
>> +++ b/kernel/trace/trace_events_hist.c
>> @@ -13,6 +13,10 @@
>>   #include <linux/rculist.h>
>>   #include <linux/tracefs.h>
>>   
>> +/* for gfp flag names */
>> +#include <linux/trace_events.h>
>> +#include <trace/events/mmflags.h>
>> +
>>   #include "tracing_map.h"
>>   #include "trace.h"
>>   #include "trace_dynevent.h"
>> @@ -752,6 +756,8 @@ static int synth_field_size(char *type)
>>   		size = sizeof(unsigned long);
>>   	else if (strcmp(type, "pid_t") == 0)
>>   		size = sizeof(pid_t);
>> +	else if (strcmp(type, "gfp_t") == 0)
>> +		size = sizeof(gfp_t);
>>   	else if (synth_field_is_string(type))
>>   		size = synth_field_string_size(type);
>>   
>> @@ -792,6 +798,8 @@ static const char *synth_field_fmt(char *type)
>>   		fmt = "%lu";
>>   	else if (strcmp(type, "pid_t") == 0)
>>   		fmt = "%d";
>> +	else if (strcmp(type, "gfp_t") == 0)
>> +		fmt = "%x";
>>   	else if (synth_field_is_string(type))
>>   		fmt = "%s";
>>   
>> @@ -834,9 +842,20 @@ static enum print_line_t
>> print_synth_event(struct trace_iterator *iter,
>>   					 i == se->n_fields - 1 ? ""
>> : " ");
>>   			n_u64 += STR_VAR_LEN_MAX / sizeof(u64);
>>   		} else {
>> +			struct trace_print_flags __flags[] = {
>> +			    __def_gfpflag_names, {-1, NULL} };
>> +
>>   			trace_seq_printf(s, print_fmt, se-
>>> fields[i]->name,
>>   					 entry->fields[n_u64],
>>   					 i == se->n_fields - 1 ? ""
>> : " ");
>> +
>> +			if (strcmp(se->fields[i]->type, "gfp_t") ==
>> 0) {
>> +				trace_seq_puts(s, " (");
>> +				trace_print_flags_seq(s, "|",
>> +						      entry-
>>> fields[n_u64],
>> +						      __flags);
>> +				trace_seq_putc(s, ')');
>> +			}
>>   			n_u64++;
>>   		}
>>   	}

-- 
Zhengjun Xing