[DTrace-devel] [PATCH 22/38] Fix aggs comment in dt_cg_tramp_prologue_act()

[Eugene Loh]

On 7/19/24 16:44, Kris Van Hees wrote:

> On Thu, Jun 27, 2024 at 01:38:48AM -0400, eugene.loh at oracle.com wrote:
>> From: Eugene Loh <eugene.loh at oracle.com>
>>
>> Signed-off-by: Eugene Loh <eugene.loh at oracle.com>
> Reviewed-by: Kris Van Hees <kris.van.hees at oracle.com>
>
> ... provided you mention in the commit msg what you are fixing.  Because
> looking at the patch you are removing a big part of a comment block but
> without any indication why, and the patch does not provide context to be
> able to assess that.

Fair enough.  I suppose I never really knew why, other than that the 
comment didn't match the code.  Okay, I did my homework and added
         Since 2dd92c02 ("Add support for aggregation keys") removed a bunch
         of code, the corresponding comments should also have been removed.
to the commit msg, along with your R_b.

>> diff --git a/libdtrace/dt_cg.c b/libdtrace/dt_cg.c
>> @@ -372,17 +372,6 @@ dt_cg_tramp_prologue_act(dt_pcb_t *pcb, dt_activity_t act)
>>   	 *	if (rc == 0)		// jeq %r0, 0, lbl_exit
>>   	 *		goto exit;
>>   	 *
>> -	 *	key = 0;		// stdw [%r9 + DCTX_AGG], 0
>> -	 *	rc = bpf_map_lookup_elem(rc, &key);
>> -	 *				// mov %r1, %r0
>> -	 *				// mov %r2, %r9
>> -	 *				// add %r2, DCTX_AGG
>> -	 *				// call bpf_map_lookup_elem
>> -	 *				//     (%r1 ... %r5 clobbered)
>> -	 *				//     (%r0 = aggs[cpuid] BPF map value)
>> -	 *	if (rc == 0)		// jeq %r0, 0, lbl_exit
>> -	 *		goto exit;
>> -	 *
>>   	 *	dctx.aggs = rc;		// stdw [%r9 + DCTX_AGG], %r0
>>   	 */
>>   	if (dtp->dt_maxaggdsize > 0) {