Messages in this thread Patch in this message | | | Date | Fri, 1 Jul 2022 12:11:56 +0100 | From | Sudeep Holla <> | Subject | Re: [PATCH v5 09/19] arch_topology: Use the last level cache information from the cacheinfo |
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On Thu, Jun 30, 2022 at 10:07:49PM +0000, Conor.Dooley@microchip.com wrote: > > > On 30/06/2022 21:21, Sudeep Holla wrote: > > On Thu, Jun 30, 2022 at 08:13:55PM +0000, Conor.Dooley@microchip.com wrote: > >> > >> I didn't have the time to go digging into things, but the following > >> macro looked odd: > >> #define per_cpu_cacheinfo_idx(cpu, idx) \ > >> (per_cpu_cacheinfo(cpu) + (idx)) > >> Maybe it is just badly named, but is this getting the per_cpu_cacheinfo > >> and then incrementing intentionally, or is it meant to get the > >> per_cpu_cacheinfo of cpu + idx? > > > > OK, basically per_cpu_cacheinfo(cpu) get the information for a cpu > > while per_cpu_cacheinfo_idx(cpu, idx) will fetch the information for a > > given cpu and given index within the cpu. So we are incrementing the > > pointer by the index. These work just fine on arm64 platform. > > Right, that's what I figured but wanted to be sure. >
OK
> > > > Not sure if compiler is optimising something as I still can't understand > > how we can end up with valid llc but fw_token as NULL. > See idk about that. The following fails to boot. > index 167abfa6f37d..9d45c37fb004 100644 > --- a/drivers/base/cacheinfo.c > +++ b/drivers/base/cacheinfo.c > @@ -36,6 +36,8 @@ struct cpu_cacheinfo *get_cpu_cacheinfo(unsigned int cpu) > static inline bool cache_leaves_are_shared(struct cacheinfo *this_leaf, > struct cacheinfo *sib_leaf) > { > + if (!this_leaf || !sib_leaf) > + return false;
Did you hit this ?
> /* > * For non DT/ACPI systems, assume unique level 1 caches, > * system-wide shared caches for all other levels. This will be used > @@ -74,8 +76,12 @@ bool last_level_cache_is_shared(unsigned int cpu_x, unsigned int cpu_y) > > llc_x = per_cpu_cacheinfo_idx(cpu_x, cache_leaves(cpu_x) - 1); > llc_y = per_cpu_cacheinfo_idx(cpu_y, cache_leaves(cpu_y) - 1); > + if (!llc_x || !llc_y){ > + printk("llc was null\n");
Or this ?
> + return false; > + } > > - return cache_leaves_are_shared(llc_x, llc_y); > + return false; //cache_leaves_are_shared(llc_x, llc_y);
Even the above change fails to boot ? Coz you are always returning false here too.
> } > > #ifdef CONFIG_OF > > and this boots: > > diff --git a/drivers/base/cacheinfo.c b/drivers/base/cacheinfo.c > index 167abfa6f37d..01900908fe31 100644 > --- a/drivers/base/cacheinfo.c > +++ b/drivers/base/cacheinfo.c > @@ -36,6 +36,8 @@ struct cpu_cacheinfo *get_cpu_cacheinfo(unsigned int cpu) > static inline bool cache_leaves_are_shared(struct cacheinfo *this_leaf, > struct cacheinfo *sib_leaf) > { > + if (!this_leaf || !sib_leaf) > + return false; > /* > * For non DT/ACPI systems, assume unique level 1 caches, > * system-wide shared caches for all other levels. This will be used > @@ -75,7 +77,7 @@ bool last_level_cache_is_shared(unsigned int cpu_x, unsigned int cpu_y) > llc_x = per_cpu_cacheinfo_idx(cpu_x, cache_leaves(cpu_x) - 1); > llc_y = per_cpu_cacheinfo_idx(cpu_y, cache_leaves(cpu_y) - 1); >
You are just missing the checks for llc_x and llc_y and it works which means llc_x and llc_y is where things are going wrong.
-- Regards, Sudeep
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