On 22.06.20 г. 17:21 ч., David Sterba wrote:
> On Fri, Jun 19, 2020 at 03:24:45PM +0300, Nikolay Borisov wrote:
>> While looking at tracepoint dumps with trace-cmd report I observed that
>> tracepoints that should have printed text instead of raw values weren't
>> doing so:
>>
>> 13 kworker/u8:1-61 [000] 66.299527: btrfs_flush_space: 5302ee13-c65e-45bb-98ef-8fe3835bd943: state=3(0x3) flags=4(METADATA) num_bytes=2621440 ret=0
>>
>> In the above line instead of (0x3) BTRFS_RESERVE_FLUSH_ALL should be printed. I.e
>> the correct output should be:
>>
>> 6 fio-370 [002] 56.762402: btrfs_trigger_flush: d04cd7ac-38e2-452f-a7f5-8157529fd5f0: preempt: flush=3(BTRFS_RESERVE_FLUSH_ALL) flags=4(METADATA) bytes=655360
>>
>> Investigating this turned out to be caused because enum values weren't exported
>> to user space via TRACE_DEFINE_ENUM. This is required in order for user space
>> tools to correctly map the raw binary values to their textual representation.
>> More information can be found in commit 190f0b76ca49 ("mm: tracing: Export enums in tracepoints to user space")
>>
>> This series follows the approach taken by 190f0b76ca49 in defining the various
>> enum mapping structures.
>
> So I see where the unintuitive naming EM and EMe comes from, but ok
> let's stick to that.
Yeah, the difference between EM and EMe is the ending comma that's
needed when actually defining the array passed to __print_symbols.
>
> I've looked at the result and it could really use the comments from
> 190f0b76ca49 where the definitions switch the output and some whitespace
> fixups in the new definitions.
>
> Not all enums are converted, just search for use of __print_symbolic
> inside the show_TYPE helpers (eg. show_ref_action, show_ref_type),
> please add them too. Thanks.
I beg you to differ:
show_ref_action/show_ref_type/__show_root_type/__show_map_type/ - those
are defined and they are OK as is, because defines don't emit separate
symbols. However, when/if in the future those defines are switched to
enums then the respective tracepoint code should be converted to using
the EM macros as well.
>
