Re: 6.6.78: timerlat_{hist,top} fail to build

[Greg KH <gregkh@linuxfoundation.org>]

On Thu, Feb 20, 2025 at 03:03:29PM +0100, Guillaume Morin wrote:
> On 19 Feb 16:03, Tomas Glozar wrote:
> >
> > Hello,
> > 
> > st 19. 2. 2025 v 15:48 odesílatel Guillaume Morin
> > <guillaume@morinfr.org> napsal:
> > >
> > > Hello,
> > >
> > > The following patches prevent Linux 6.6.78+ rtla to build:
> > >
> > > - "rtla/timerlat_top: Set OSNOISE_WORKLOAD for kernel threads" (stable
> > > commit 41955b6c268154f81e34f9b61cf8156eec0730c0)
> > > - "rtla/timerlat_hist: Set OSNOISE_WORKLOAD for kernel threads" (stable
> > > commit 83b74901bdc9b58739193b8ee6989254391b6ba7)
> > >
> > > Both were added to Linux 6.6.78 based on the Fixes tag in the upstream
> > > commits.
> > >
> > > These patches prevent 6.6.78 rta to build with a similar error (missing
> > > kernel_workload in the params struct)
> > > src/timerlat_top.c:687:52: error: ‘struct timerlat_top_params’ has no member named ‘kernel_workload’
> > >
> > 
> > I did not realize that, sorry!
> > 
> > > These patches appear to depend on "rtla/timerlat: Make user-space
> > > threads the default" commit fb9e90a67ee9a42779a8ea296a4cf7734258b27d
> > > which is not present in 6.6.
> > >
> > > I am not sure if it's better to revert them or pick up
> > > fb9e90a67ee9a42779a8ea296a4cf7734258b27d in 6.6. Tomas, what do you
> > > think?
> > >
> > 
> > We don't want to pick up fb9e90a67ee9a42779a8ea296a4cf7734258b27d
> > (rtla/timerlat: Make user-space threads the default) to stable, since
> > it changes the default behavior as well as output of rtla.
> > 
> > The patches can be fixed by by substituting params->kernel_workload
> > for !params->user_hist (!params->user_top) for the version of the
> > files that is present in 6.6-stable (6.1-stable is not affected, since
> > it doesn't have user workload mode at all).
> > 
> > I'm not sure what the correct procedure would be. One way I can think
> > of is reverting the patch as broken, and me sending an alternate
> > version of the patch for 6.6-stable containing the change above. That
> > would be the cleanest way in my opinion (as compared to sending the
> > fixup directly).
> 
> Either way would work for me. Not sure what Greg prefers however

I prefer to take whatever is upstream, and if that doesn't work, and
these were applied incorrectly, we can just revert them.

thanks,

greg k-h