Re: [PATCH RFC v1 0/4] perf: Introduce extended syscall error reporting

From: Alexander Shishkin
Date: Mon Aug 24 2015 - 09:52:12 EST

Ingo Molnar <mingo@xxxxxxxxxx> writes:

> * Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
>> On Fri, Jul 24, 2015 at 02:45:55PM +0300, Alexander Shishkin wrote:
>> > Hi Peter and Ingo and everybody,
>> >
>> > Here's my second stab at improving perf's error reporting by attaching
>> > arbitrary strings to the integer error codes. This is largely based
>> > off of the previous email thread [1].
>> >
>> > This time around, I employed a linker trick to convert the structures
>> > containing extended error information into integers, which are then
>> > made to look just like normal error codes so that IS_ERR_VALUE() and
>> > friends would still work correctly on them. So no extra pointers in
>> > the struct perf_event or anywhere else; the extended error codes are
>> > passed around like normal error codes. They only need to be converted
>> > in syscalls' topmost return statements. This is done in 1/4.
>> >
>> > Then, 2/4 illustrates how error sites can be extended to include more
>> > information such as file names and line numbers [1].
>> >
>> > The other two patches add perf_err() annotation to a few semi-randomly
>> > picked places in perf core (3/4) and x86 bits (4/4).
>> Looks generally ok to me. Thanks for doing this.
> I like this too.
> Alexander, mind sending a finalized, signed off version?

Sure, I have everything ready, except for what about 2/4 (using
CONFIG_DEBUG_KERNEL to extend output with file name and line number)?
Should I leave it out or can we pick a more specific kconfig option or
add a new one?

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