linux-kernel - Re: [PATCH v1 4/5] perf mem: Support record for hybrid platform

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Message-ID: <aa5f0be5-c939-3c26-9d2a-3a073449bf98@linux.intel.com>
Date:   Tue, 25 May 2021 15:39:39 +0800
From:   "Jin, Yao" <yao.jin@...ux.intel.com>
To:     Jiri Olsa <jolsa@...hat.com>
Cc:     acme@...nel.org, jolsa@...nel.org, peterz@...radead.org,
        mingo@...hat.com, alexander.shishkin@...ux.intel.com,
        Linux-kernel@...r.kernel.org, ak@...ux.intel.com,
        kan.liang@...el.com, yao.jin@...el.com
Subject: Re: [PATCH v1 4/5] perf mem: Support record for hybrid platform

Hi Jiri,

>>>       rec_argv = calloc(rec_argc + 1, sizeof(char *));
>>>       if (!rec_argv)
>>>           return -1;
>>> +    /*
>>> +     * Save the allocated event name strings.
>>> +     */
>>> +    rec_tmp = calloc(rec_argc + 1, sizeof(char *));
>>> +    if (!rec_tmp) {
>>> +        free(rec_argv);
>>> +        return -1;
>>> +    }
>>
>> why not do strdup on all of them and always call free instead?
>> that would get rid of the rec_tmp and tmp_nr
>>
> 
> That is also one method. Let me try it.
> 

If we do strdup on all of them, such as,

	if (e->record)
		rec_argv[i++] = strdup("-W");

	rec_argv[i++] = strdup("-d");

	if (mem->phys_addr)
		rec_argv[i++] = strdup("--phys-data");
	....

That looks too much strdup used here. So I choose to use a rec_tmp[] to record the allocated string 
and free them before exit the function.

Or we record the start index and end index in rec_argv[] for the allocated event string, use strdup 
on them and call free before exit the function.

What do you think?

Thanks
Jin Yao