wireguard-linux/arch/x86/kernel/cpu/resctrl/rdtgroup.c, branch update-toolchain

x86/resctrl: Fill out rmid_read structure for smp_call*() to read a counter

2024-07-02T17:57:19Z

mon_event_read() fills out most fields of the struct rmid_read that is passed via an smp_call*() function to a CPU that is part of the correct domain to read the monitor counters. With Sub-NUMA Cluster (SNC) mode there are now two cases to handle: 1) Reading a file that returns a value for a single domain. + Choose the CPU to execute from the domain cpu_mask 2) Reading a file that must sum across domains sharing an L3 cache instance. + Indicate to called code that a sum is needed by passing a NULL rdt_mon_domain pointer. + Choose the CPU from the L3 shared_cpu_map. Signed-off-by: Tony Luck Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Reinette Chatre Tested-by: Babu Moger Link: https://lore.kernel.org/r/20240628215619.76401-16-tony.luck@intel.com

x86/resctrl: Handle removing directories in Sub-NUMA Cluster (SNC) mode

2024-07-02T17:51:06Z

In SNC mode, there are multiple subdirectories in each L3 level monitor directory (one for each SNC node). If all the CPUs in an SNC node are taken offline, just remove the SNC directory for that node. In non-SNC mode, or when the last SNC node directory is removed, remove the L3 monitor directory. Add a helper function to avoid duplicated code. Signed-off-by: Tony Luck Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Reinette Chatre Link: https://lore.kernel.org/r/20240702173820.90368-2-tony.luck@intel.com

x86/resctrl: Create Sub-NUMA Cluster (SNC) monitor files

2024-07-02T17:49:54Z

When SNC mode is enabled, create subdirectories and files to monitor at the SNC node granularity. Legacy behavior is preserved by tagging the monitor files at the L3 granularity with the "sum" attribute. When the user reads these files the kernel will read monitor data from all SNC nodes that share the same L3 cache instance and return the aggregated value to the user. Note that the "domid" field for files that must sum across SNC domains has the L3 cache instance id, while non-summing files use the domain id. The "sum" files do not need to make a call to mon_event_read() to initialize the MBM counters. This will be handled by initializing the individual SNC nodes that share the L3. Signed-off-by: Tony Luck Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Reinette Chatre Tested-by: Babu Moger Link: https://lore.kernel.org/r/20240628215619.76401-14-tony.luck@intel.com

x86/resctrl: Refactor mkdir_mondata_subdir() with a helper function

2024-07-02T17:49:54Z

In Sub-NUMA Cluster (SNC) mode Linux must create the monitor files in the original "mon_L3_XX" directories and also in each of the "mon_sub_L3_YY" directories. Refactor mkdir_mondata_subdir() to move the creation of monitoring files into a helper function to avoid the need to duplicate code later. No functional change. Signed-off-by: Tony Luck Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Reinette Chatre Tested-by: Babu Moger Link: https://lore.kernel.org/r/20240628215619.76401-12-tony.luck@intel.com

x86/resctrl: Initialize on-stack struct rmid_read instances

2024-07-02T17:49:54Z

New semantics rely on some struct rmid_read members having NULL values to distinguish between the SNC and non-SNC scenarios. resctrl can thus no longer rely on this struct not being initialized properly. Initialize all on-stack declarations of struct rmid_read: rdtgroup_mondata_show() mbm_update() mkdir_mondata_subdir() to ensure that garbage values from the stack are not passed down to other functions. [ bp: Massage commit message. ] Signed-off-by: Tony Luck Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Reinette Chatre Tested-by: Babu Moger Link: https://lore.kernel.org/r/20240628215619.76401-11-tony.luck@intel.com

x86/resctrl: Prepare for new Sub-NUMA Cluster (SNC) monitor files

2024-07-02T17:49:54Z

When SNC is enabled, monitoring data is collected at the SNC node granularity, but must be reported at L3-cache granularity for backwards compatibility in addition to reporting at the node level. Add a "ci" field to the rdt_mon_domain structure to save the cache information about the enclosing L3 cache for the domain. This provides: 1) The cache id which is needed to compose the name of the legacy monitoring directory, and to determine which domains should be summed to provide L3-scoped data. 2) The shared_cpu_map which is needed to determine which CPUs can be used to read the RMID counters with the MSR interface. This is the first step to an eventual goal of monitor reporting files like this (for a system with two SNC nodes per L3): $ cd /sys/fs/resctrl/mon_data $ tree mon_L3_00 mon_L3_00 <- 00 here is L3 cache id ├── llc_occupancy \ These files provide legacy support ├── mbm_local_bytes > for non-SNC aware monitor apps ├── mbm_total_bytes / that expect data at L3 cache level ├── mon_sub_L3_00 <- 00 here is SNC node id │ ├── llc_occupancy \ These files are finer grained │ ├── mbm_local_bytes > data from each SNC node │ └── mbm_total_bytes / └── mon_sub_L3_01 ├── llc_occupancy \ ├── mbm_local_bytes > As above, but for node 1. └── mbm_total_bytes / [ bp: Massage commit message. ] Signed-off-by: Tony Luck Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Reinette Chatre Tested-by: Babu Moger Link: https://lore.kernel.org/r/20240628215619.76401-9-tony.luck@intel.com

x86/resctrl: Block use of mba_MBps mount option on Sub-NUMA Cluster (SNC) systems

2024-07-02T17:49:54Z

When SNC is enabled there is a mismatch between the MBA control function which operates at L3 cache scope and the MBM monitor functions which measure memory bandwidth on each SNC node. Block use of the mba_MBps when scopes for MBA/MBM do not match. Improve user diagnostics by adding invalfc() message when mba_MBps is not supported. Signed-off-by: Tony Luck Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Reinette Chatre Tested-by: Babu Moger Link: https://lore.kernel.org/r/20240628215619.76401-8-tony.luck@intel.com

x86/resctrl: Split the rdt_domain and rdt_hw_domain structures

2024-07-02T17:49:54Z

The same rdt_domain structure is used for both control and monitor functions. But this results in wasted memory as some of the fields are only used by control functions, while most are only used for monitor functions. Split into separate rdt_ctrl_domain and rdt_mon_domain structures with just the fields required for control and monitoring respectively. Similar split of the rdt_hw_domain structure into rdt_hw_ctrl_domain and rdt_hw_mon_domain. Signed-off-by: Tony Luck Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Reinette Chatre Tested-by: Babu Moger Link: https://lore.kernel.org/r/20240628215619.76401-5-tony.luck@intel.com

x86/resctrl: Prepare for different scope for control/monitor operations

2024-07-02T17:49:53Z

Resctrl assumes that control and monitor operations on a resource are performed at the same scope. Prepare for systems that use different scope (specifically Intel needs to split the RDT_RESOURCE_L3 resource to use L3 scope for cache control and NODE scope for cache occupancy and memory bandwidth monitoring). Create separate domain lists for control and monitor operations. Note that errors during initialization of either control or monitor functions on a domain would previously result in that domain being excluded from both control and monitor operations. Now the domains are allocated independently it is no longer required to disable both control and monitor operations if either fail. Signed-off-by: Tony Luck Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Reinette Chatre Tested-by: Babu Moger Link: https://lore.kernel.org/r/20240628215619.76401-4-tony.luck@intel.com

x86/resctrl: Prepare to split rdt_domain structure

2024-07-02T17:49:53Z

The rdt_domain structure is used for both control and monitor features. It is about to be split into separate structures for these two usages because the scope for control and monitoring features for a resource will be different for future resources. To allow for common code that scans a list of domains looking for a specific domain id, move all the common fields ("list", "id", "cpu_mask") into their own structure within the rdt_domain structure. Signed-off-by: Tony Luck Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Reinette Chatre Tested-by: Babu Moger Link: https://lore.kernel.org/r/20240628215619.76401-3-tony.luck@intel.com