RE: [PATCH RFC v3 1/6] cxl/trace: Remove uuid from event trace known events

[Ira Weiny]

Shiju Jose wrote:
> 
> 
> >-----Original Message-----
> >From: Jonathan Cameron <jonathan.cameron@xxxxxxxxxx>
> >Sent: 03 November 2023 14:28
> >To: Ira Weiny <ira.weiny@xxxxxxxxx>
> >Cc: Dan Williams <dan.j.williams@xxxxxxxxx>; Smita Koralahalli
> ><Smita.KoralahalliChannabasappa@xxxxxxx>; Yazen Ghannam
> ><yazen.ghannam@xxxxxxx>; Davidlohr Bueso <dave@xxxxxxxxxxxx>; Dave
> >Jiang <dave.jiang@xxxxxxxxx>; Alison Schofield <alison.schofield@xxxxxxxxx>;
> >Vishal Verma <vishal.l.verma@xxxxxxxxx>; Ard Biesheuvel <ardb@xxxxxxxxxx>;
> >linux-efi@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; linux-
> >cxl@xxxxxxxxxxxxxxx; Shiju Jose <shiju.jose@xxxxxxxxxx>
> >Subject: Re: [PATCH RFC v3 1/6] cxl/trace: Remove uuid from event trace known
> >events
> >
> >On Wed, 01 Nov 2023 14:11:18 -0700
> >Ira Weiny <ira.weiny@xxxxxxxxx> wrote:
> >
> >> The uuid printed in the well known events is redundant.  The uuid
> >> defines what the event was.
> >>
> >> Remove the uuid from the known events and only report it in the
> >> generic event as it remains informative there.
> >>
> >> Reviewed-by: Davidlohr Bueso <dave@xxxxxxxxxxxx>
> >> Reviewed-by: Dan Williams <dan.j.williams@xxxxxxxxx>
> >> Signed-off-by: Ira Weiny <ira.weiny@xxxxxxxxx>
> >
> >Removing the print is fine, but look like this also removes the actual trace point
> >field.  That's userspace ABI.  Expanding it is fine, but taking fields away is more
> >problematic.
> >
> >Are we sure we don't break anyone?  Shiju, will rasdaemon be fine with this
> >change?
> 
> The field hdr_uuid is removed from the common CXL_EVT_TP_entry shared by the
> trace events cxl_generic_event, cxl_general_media, cxl_dram and cxl_memory_module .
> rasdaemon will break because of this while processing these trace events
> and also affects the corresponding error records in the SQLite data base. 
> Rasdaemon needs update to avoid this.
>  

Ok we can leave the uuid field in easy enough.

But does rasdaemon use the value of the field for anything?  In other
words does CPER record processing need to generate a proper UUID value?

Ira