Messages in this thread Patch in this message | | | From | <> | Subject | Re: [PATCH v5 09/19] arch_topology: Use the last level cache information from the cacheinfo | Date | Fri, 1 Jul 2022 14:47:16 +0000 |
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On 01/07/2022 12:11, Sudeep Holla wrote: > EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe > > 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 ?
Ah I forgot to remove this, I had added it (since I knew a return value of false was correct) but it was still failing to boot. It was my step prior to adding the if(!llc...
> >> /* >> * 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 ?
This printk never prints out.
> >> + 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.
Correct, fails to boot.
> >> } >> >> #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. >
Sounds about right to me.
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