Re: [PATCH v6 00/21] arch_topology: Updates to add socket support and fix cluster ids

[<Conor.Dooley@microchip.com>]

On 04/07/2022 11:15, Sudeep Holla wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
> 
> Hi Greg,
> 
> Let me know if you prefer to pull the patches directly or prefer pull
> request. It has been in -next for a while now.
> 
> Hi All,
> 
> This version updates cacheinfo to populate and use the information from
> there for all the cache topology.
> 
> This series intends to fix some discrepancies we have in the CPU topology
> parsing from the device tree /cpu-map node. Also this diverges from the
> behaviour on a ACPI enabled platform. The expectation is that both DT
> and ACPI enabled systems must present consistent view of the CPU topology.
> 
> Currently we assign generated cluster count as the physical package identifier
> for each CPU which is wrong. The device tree bindings for CPU topology supports
> sockets to infer the socket or physical package identifier for a given CPU.
> Also we don't check if all the cores/threads belong to the same cluster before
> updating their sibling masks which is fine as we don't set the cluster id yet.
> 
> These changes also assigns the cluster identifier as parsed from the device tree
> cluster nodes within /cpu-map without support for nesting of the clusters.
> Finally, it also add support for socket nodes in /cpu-map. With this the
> parsing of exact same information from ACPI PPTT and /cpu-map DT node
> aligns well.
> 
> The only exception is that the last level cache id information can be
> inferred from the same ACPI PPTT while we need to parse CPU cache nodes
> in the device tree.

For DT + RISC-V on PolarFire SoC and SiFive fu540
Tested-by: Conor Dooley <conor.dooley@microchip.com>

Anecdotally, v5 was tested on the !SMP D1 which worked fine when
CONFIG_SMP was enabled.

Thanks,
Conor.

> 
> 
> v5[5]->v6:
>         - Handled out of memory case in early detected correctly after
>           Conor reported boot failures on some RISC-V platform. Also
>           added a log to show up failure of early cacheinfo detection.
>         - Added "Remove the unused find_acpi_cpu_cache_topology()" which
>           was missed earlier and posted separately
>         - Added all the additional tags recieved
> 
> v4[4]->v5[5]:
>         - Added all the tags recieved so far. Rafael has acked only change
>           in ACPI and Catalin has acked only change in arm64.
>         - Addressed all the typos pointed by Ionela and dropped the patch
>           removing the checks for invalid package id as discussed and update
>           depth in nested cluster warning check.
> 
> v3[3]->v4[4]:
>         - Updated ACPI PPTT fw_token to use table offset instead of virtual
>           address as it could get changed for everytime it is mapped before
>           the global acpi_permanent_mmap is set
>         - Added warning for the topology with nested clusters
>         - Added update to cpu_clustergroup_mask so that introduction of
>           correct cluster_id doesn't break existing platforms by limiting
>           the span of clustergroup_mask(by Ionela)
> 
> v2[2]->v3[3]:
>         - Dropped support to get the device node for the CPU's LLC
>         - Updated cacheinfo to support calling of detect_cache_attributes
>           early in smp_prepare_cpus stage
>         - Added support to check if LLC is valid and shared in the cacheinfo
>         - Used the same in arch_topology
> 
> v1[1]->v2[2]:
>         - Updated ID validity check include all non-negative value
>         - Added support to get the device node for the CPU's last level cache
>         - Added support to build llc_sibling on DT platforms
> 
> [1] https://lore.kernel.org/lkml/20220513095559.1034633-1-sudeep.holla@arm.com
> [2] https://lore.kernel.org/lkml/20220518093325.2070336-1-sudeep.holla@arm.com
> [3] https://lore.kernel.org/lkml/20220525081416.3306043-1-sudeep.holla@arm.com
> [4] https://lore.kernel.org/lkml/20220621192034.3332546-1-sudeep.holla@arm.com
> [5] https://lore.kernel.org/lkml/20220627165047.336669-1-sudeep.holla@arm.com
> 
> Ionela Voinescu (1):
>   arch_topology: Limit span of cpu_clustergroup_mask()
> 
> Sudeep Holla (20):
>   ACPI: PPTT: Use table offset as fw_token instead of virtual address
>   cacheinfo: Use of_cpu_device_node_get instead cpu_dev->of_node
>   cacheinfo: Add helper to access any cache index for a given CPU
>   cacheinfo: Move cache_leaves_are_shared out of CONFIG_OF
>   cacheinfo: Add support to check if last level cache(LLC) is valid or shared
>   cacheinfo: Allow early detection and population of cache attributes
>   cacheinfo: Use cache identifiers to check if the caches are shared if available
>   cacheinfo: Align checks in cache_shared_cpu_map_{setup,remove} for readability
>   arch_topology: Add support to parse and detect cache attributes
>   arch_topology: Use the last level cache information from the cacheinfo
>   arm64: topology: Remove redundant setting of llc_id in CPU topology
>   arch_topology: Drop LLC identifier stash from the CPU topology
>   arch_topology: Set thread sibling cpumask only within the cluster
>   arch_topology: Check for non-negative value rather than -1 for IDs validity
>   arch_topology: Avoid parsing through all the CPUs once a outlier CPU is found
>   arch_topology: Don't set cluster identifier as physical package identifier
>   arch_topology: Set cluster identifier in each core/thread from /cpu-map
>   arch_topology: Add support for parsing sockets in /cpu-map
>   arch_topology: Warn that topology for nested clusters is not supported
>   ACPI: Remove the unused find_acpi_cpu_cache_topology()
> 
>  arch/arm64/kernel/topology.c  |  14 ----
>  drivers/acpi/pptt.c           |  40 +---------
>  drivers/base/arch_topology.c  | 102 ++++++++++++++++++------
>  drivers/base/cacheinfo.c      | 143 ++++++++++++++++++++++------------
>  include/linux/acpi.h          |   5 --
>  include/linux/arch_topology.h |   1 -
>  include/linux/cacheinfo.h     |   3 +
>  7 files changed, 175 insertions(+), 133 deletions(-)
> 
> --
> 2.37.0
>