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Groups > linux.kernel > #1310373
| From | Stephane Eranian <eranian@google.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [RFC] perf record: missing buildid for callstack modules |
| Date | 2016-01-15 20:00 +0100 |
| Message-ID | <qRhLk-1DX-13@gated-at.bofh.it> (permalink) |
| References | (6 earlier) <qQt2a-8ek-13@gated-at.bofh.it> <qQOgi-6eV-13@gated-at.bofh.it> <qQOpX-6iM-1@gated-at.bofh.it> <qR1Qe-7rW-7@gated-at.bofh.it> <qR91p-49P-27@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Fri, Jan 15, 2016 at 1:34 AM, Peter Zijlstra <peterz@infradead.org> wrote:
> On Thu, Jan 14, 2016 at 05:59:48PM -0800, Stephane Eranian wrote:
>> Peter,
>>
>> On Thu, Jan 14, 2016 at 3:36 AM, Peter Zijlstra <peterz@infradead.org> wrote:
>> > On Thu, Jan 14, 2016 at 12:27:34PM +0100, Ingo Molnar wrote:
>> >> > + * u32 filename_len;
>> >> > + * char filename[2+];
>> >
>> >> Acked-by: Ingo Molnar <mingo@kernel.org>
>> >
>> > except of course that sizeof(u32) == 4 :/
>
>> There is no padding here. Are you concerned about running out of bits
>> in filename_len?
>
> No, I just made a mess of it :-)
>
> filename_len should have been u16 and filename should then be 6+8n in
> size.
>
why don't you make it more explicit:
u16 filename_len
u16 extra_len
then it would be clear what is what, no field with dual meaning.
Now, that assumes that no pathname can be longer than 65535 bytes.
>> Any extension possible because header.size - sizeof(mmap3) -
>> filename_len sizing what's after filename, right?
>
> Right, current MMAP records use the remaining size as the filename
> length, but by explicitly specifying that we can add optional fields.
>
> These fields must be after filename_len, otherwise you'd not be able to
> find filename_len and you could not compute the extra size. And given
> alignment constraints it makes sense to do it after filename[].
>
> So suppose we wanted to also add atime and ctime, we could do.
>
> PERF_RECORD_MMAP3 {
> ...
> u16 filename_len;
> char filename[6+8n];
>
> if (extra_size >= 16) {
> u64 stime;
> u64 ctime;
> };
> }
>
> or something like that.
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Re: [RFC] perf record: missing buildid for callstack modules Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-07 23:00 +0100
Re: [RFC] perf record: missing buildid for callstack modules Stephane Eranian <eranian@google.com> - 2016-01-07 23:10 +0100
Re: [RFC] perf record: missing buildid for callstack modules Namhyung Kim <namhyung@gmail.com> - 2016-01-08 00:30 +0100
Re: [RFC] perf record: missing buildid for callstack modules Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 00:50 +0100
Re: [RFC] perf record: missing buildid for callstack modules Stephane Eranian <eranian@google.com> - 2016-01-08 19:10 +0100
Re: [RFC] perf record: missing buildid for callstack modules Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:20 +0100
Re: [RFC] perf record: missing buildid for callstack modules Peter Zijlstra <peterz@infradead.org> - 2016-01-11 18:40 +0100
Re: [RFC] perf record: missing buildid for callstack modules Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-11 19:30 +0100
Re: [RFC] perf record: missing buildid for callstack modules Stephane Eranian <eranian@google.com> - 2016-01-11 21:10 +0100
Re: [RFC] perf record: missing buildid for callstack modules Ingo Molnar <mingo@kernel.org> - 2016-01-12 11:50 +0100
Re: [RFC] perf record: missing buildid for callstack modules Peter Zijlstra <peterz@infradead.org> - 2016-01-12 12:40 +0100
Re: [RFC] perf record: missing buildid for callstack modules Ingo Molnar <mingo@kernel.org> - 2016-01-12 13:20 +0100
Re: [RFC] perf record: missing buildid for callstack modules Peter Zijlstra <peterz@infradead.org> - 2016-01-12 14:50 +0100
Re: [RFC] perf record: missing buildid for callstack modules Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-12 15:40 +0100
Re: [RFC] perf record: missing buildid for callstack modules Peter Zijlstra <peterz@infradead.org> - 2016-01-12 16:40 +0100
Re: [RFC] perf record: missing buildid for callstack modules Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-12 16:50 +0100
Re: [RFC] perf record: missing buildid for callstack modules Peter Zijlstra <peterz@infradead.org> - 2016-01-12 17:20 +0100
Re: [RFC] perf record: missing buildid for callstack modules Peter Zijlstra <peterz@infradead.org> - 2016-01-12 17:30 +0100
Re: [RFC] perf record: missing buildid for callstack modules Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-12 18:20 +0100
Re: [RFC] perf record: missing buildid for callstack modules Ingo Molnar <mingo@kernel.org> - 2016-01-13 11:30 +0100
Re: [RFC] perf record: missing buildid for callstack modules Peter Zijlstra <peterz@infradead.org> - 2016-01-13 13:50 +0100
Re: [RFC] perf record: missing buildid for callstack modules Ingo Molnar <mingo@kernel.org> - 2016-01-14 12:30 +0100
Re: [RFC] perf record: missing buildid for callstack modules Peter Zijlstra <peterz@infradead.org> - 2016-01-14 12:40 +0100
Re: [RFC] perf record: missing buildid for callstack modules Stephane Eranian <eranian@google.com> - 2016-01-15 03:00 +0100
Re: [RFC] perf record: missing buildid for callstack modules Peter Zijlstra <peterz@infradead.org> - 2016-01-15 10:40 +0100
Re: [RFC] perf record: missing buildid for callstack modules Stephane Eranian <eranian@google.com> - 2016-01-15 20:00 +0100
Re: [RFC] perf record: missing buildid for callstack modules Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-15 20:50 +0100
Re: [RFC] perf record: missing buildid for callstack modules Stephane Eranian <eranian@google.com> - 2016-01-15 22:50 +0100
Re: [RFC] perf record: missing buildid for callstack modules Peter Zijlstra <peterz@infradead.org> - 2016-01-15 22:40 +0100
Re: [RFC] perf record: missing buildid for callstack modules Stephane Eranian <eranian@google.com> - 2016-01-12 22:10 +0100
Re: [RFC] perf record: missing buildid for callstack modules One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk> - 2016-01-12 14:10 +0100
Re: [RFC] perf record: missing buildid for callstack modules Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-12 15:40 +0100
Re: [RFC] perf record: missing buildid for callstack modules Peter Zijlstra <peterz@infradead.org> - 2016-01-12 16:40 +0100
Re: [RFC] perf record: missing buildid for callstack modules Ingo Molnar <mingo@kernel.org> - 2016-01-13 11:30 +0100
Re: [RFC] perf record: missing buildid for callstack modules Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-12 15:30 +0100
Re: [RFC] perf record: missing buildid for callstack modules Ingo Molnar <mingo@kernel.org> - 2016-01-13 11:00 +0100
Re: [RFC] perf record: missing buildid for callstack modules Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-13 16:30 +0100
Re: [RFC] perf record: missing buildid for callstack modules Namhyung Kim <namhyung@kernel.org> - 2016-01-19 16:00 +0100
Re: [RFC] perf record: missing buildid for callstack modules Peter Zijlstra <peterz@infradead.org> - 2016-01-19 16:30 +0100
Re: [RFC] perf record: missing buildid for callstack modules Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-19 16:50 +0100
Re: [RFC] perf record: missing buildid for callstack modules Namhyung Kim <namhyung@kernel.org> - 2016-01-09 11:40 +0100
Re: [RFC] perf record: missing buildid for callstack modules Adrian Hunter <adrian.hunter@intel.com> - 2016-01-11 10:40 +0100
Re: [RFC] perf record: missing buildid for callstack modules Namhyung Kim <namhyung@kernel.org> - 2016-01-11 12:10 +0100
Re: [RFC] perf record: missing buildid for callstack modules Adrian Hunter <adrian.hunter@intel.com> - 2016-01-11 13:00 +0100
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