Messages in this thread | | | Date | Wed, 17 May 2023 18:27:03 -0700 | From | Ricardo Neri <> | Subject | Re: [PATCH v4 1/3] cacheinfo: Add arch specific early level initializer |
| |
On Mon, May 15, 2023 at 10:36:08AM +0100, Sudeep Holla wrote: > On Wed, May 10, 2023 at 12:12:07PM -0700, Ricardo Neri wrote: > > Hi, > > > > I had posted a patchset[1] for x86 that initializes > > ci_cacheinfo(cpu)->num_leaves during SMP boot. > > > > It is entirely clear to me if this is just a clean up or a fix to some > issue you faced ? Just wanted to let you know Prateek from AMD has couple > of fixes [2]
My first patch is a bug fix. The second patch is clean up that results from fixing the bug in patch 1.
> > > This means that early_leaves and a late cache_leaves() are equal but > > per_cpu_cacheinfo(cpu) is never allocated. Currently, x86 does not use > > fetch_cache_info(). > > > > I think that we should check here that per_cpu_cacheinfo() has been allocated to > > take care of the case in which early and late cache leaves remain the same: > > > > - if (cache_leaves(cpu) <= early_leaves) > > + if (cache_leaves(cpu) <= early_leaves && per_cpu_cacheinfo(cpu)) > > > > Otherwise, in v6.4-rc1 + [1] I observe a NULL pointer dereference from > > last_level_cache_is_valid(). > > > > I think this is different issue as Prateek was just observing wrong info > after cpuhotplug operations. But the patches manage the cpumap_populated > state better with the patches. Can you please look at that as weel ?
I verified that the patches from Prateek fix a different issue. I was able to reproduce his issue. His patches fixes it.
I still see my issue after applying Prateek's patches. > > -- > Regards, > Sudeep > > [2] https://lore.kernel.org/all/20230508084115.1157-1-kprateek.nayak@amd.com
Thank you for the suggestion!
BR, Ricardo
| |