Re: [PATCH v1 01/31] x86/resctrl: Fix allocation of cleanest CLOSID on platforms with no monitors

[David Hildenbrand]

On 09.04.24 17:02, Reinette Chatre wrote:
> Hi David,

Hi,

> (Thank you very much for taking a look at these)

I'm planning on reviewing more; as most of resctrl is code I haven't 
really read before, I'm not able to make progress as fast as I normally 
would in core-MM ... :)

> On 4/9/2024 1:05 AM, David Hildenbrand wrote:
> > On 21.03.24 17:50, James Morse wrote:
> > > commit 6eac36bb9eb0 ("x86/resctrl: Allocate the cleanest CLOSID by
> > > searching closid_num_dirty_rmid") added a Kconfig option that causes
> > > resctrl to search for the CLOSID with the fewest dirty cache lines when
> > > creating a new control group. This depends on the values read from the
> > > llc_occupancy counters.
> > >
> > > This support missed that some platforms may not have these counters.
> > > This causes a NULL pointer dereference when creating a new control
> > > group as the array was not allocated by dom_data_init().
> > >
> > > As this feature isn't necessary on platforms that don't have cache
> > > occupancy monitors, add this to the check that occurs when a new
> > > control group is allocated.
> > >
> > > The existing code is not selected by any upstream platform, it makes
> > > no sense to backport this patch to stable.
> >
> > It's weird to not see RESCTRL_RMID_DEPENDS_ON_CLOSID appear in any Kconfig file.
> > I guess it will all make sense once the refactoring is done :)
>
> This is done later in this series where patch #29, "fs/resctrl: Add boiler
> plate for external resctrl code", introduces it to fs/resctrl/Kconfig.

Oh, already in this series, great!

--
Cheers,

David / dhildenb