kernel/linux.git/include/linux/resctrl.h, branch v6.12.80

x86/resctrl: Fix arch_mbm_* array overrun on SNC

2024-08-28T09:13:08+00:00

When using resctrl on systems with Sub-NUMA Clustering enabled, monitoring groups may be allocated RMID values which would overrun the arch_mbm_{local,total} arrays. This is due to inconsistencies in whether the SNC-adjusted num_rmid value or the unadjusted value in resctrl_arch_system_num_rmid_idx() is used. The num_rmid value for the L3 resource is currently: resctrl_arch_system_num_rmid_idx() / snc_nodes_per_l3_cache As a simple fix, make resctrl_arch_system_num_rmid_idx() return the SNC-adjusted, L3 num_rmid value on x86. Fixes: e13db55b5a0d ("x86/resctrl: Introduce snc_nodes_per_l3_cache") Signed-off-by: Peter Newman Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Reinette Chatre Link: https://lore.kernel.org/r/20240822190212.1848788-1-peternewman@google.com

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

2024-07-02T17:49:54+00:00

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: Add node-scope to the options for feature scope

2024-07-02T17:49:54+00:00

Currently supported resctrl features are all domain scoped the same as the scope of the L2 or L3 caches. Add RESCTRL_L3_NODE as a new option for features that are scoped at the same granularity as NUMA nodes. This is needed for Intel's Sub-NUMA Cluster (SNC) feature where monitoring features are divided between nodes that share an L3 cache. 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/20240628215619.76401-6-tony.luck@intel.com

x86/resctrl: Split the rdt_domain and rdt_hw_domain structures

2024-07-02T17:49:54+00:00

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

2024-07-02T17:49:53+00:00

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

2024-07-02T17:49:53+00:00

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

x86/resctrl: Prepare for new domain scope

2024-07-02T17:49:53+00:00

Resctrl resources operate on subsets of CPUs in the system with the defining attribute of each subset being an instance of a particular level of cache. E.g. all CPUs sharing an L3 cache would be part of the same domain. In preparation for features that are scoped at the NUMA node level, change the code from explicit references to "cache_level" to a more generic scope. At this point the only options for this scope are groups of CPUs that share an L2 cache or L3 cache. Clean up the error handling when looking up domains. Report invalid ids before calling rdt_find_domain() in preparation for better messages when scope can be other than cache scope. This means that rdt_find_domain() will never return an error. So remove checks for error from the call sites. 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/20240628215619.76401-2-tony.luck@intel.com

x86/resctrl: Separate arch and fs resctrl locks

2024-02-19T18:28:07+00:00

resctrl has one mutex that is taken by the architecture-specific code, and the filesystem parts. The two interact via cpuhp, where the architecture code updates the domain list. Filesystem handlers that walk the domains list should not run concurrently with the cpuhp callback modifying the list. Exposing a lock from the filesystem code means the interface is not cleanly defined, and creates the possibility of cross-architecture lock ordering headaches. The interaction only exists so that certain filesystem paths are serialised against CPU hotplug. The CPU hotplug code already has a mechanism to do this using cpus_read_lock(). MPAM's monitors have an overflow interrupt, so it needs to be possible to walk the domains list in irq context. RCU is ideal for this, but some paths need to be able to sleep to allocate memory. Because resctrl_{on,off}line_cpu() take the rdtgroup_mutex as part of a cpuhp callback, cpus_read_lock() must always be taken first. rdtgroup_schemata_write() already does this. Most of the filesystem code's domain list walkers are currently protected by the rdtgroup_mutex taken in rdtgroup_kn_lock_live(). The exceptions are rdt_bit_usage_show() and the mon_config helpers which take the lock directly. Make the domain list protected by RCU. An architecture-specific lock prevents concurrent writers. rdt_bit_usage_show() could walk the domain list using RCU, but to keep all the filesystem operations the same, this is changed to call cpus_read_lock(). The mon_config helpers send multiple IPIs, take the cpus_read_lock() in these cases. The other filesystem list walkers need to be able to sleep. Add cpus_read_lock() to rdtgroup_kn_lock_live() so that the cpuhp callbacks can't be invoked when file system operations are occurring. Add lockdep_assert_cpus_held() in the cases where the rdtgroup_kn_lock_live() call isn't obvious. Resctrl's domain online/offline calls now need to take the rdtgroup_mutex themselves. [ bp: Fold in a build fix: https://lore.kernel.org/r/87zfvwieli.ffs@tglx ] Signed-off-by: James Morse Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Shaopeng Tan Reviewed-by: Reinette Chatre Reviewed-by: Babu Moger Tested-by: Shaopeng Tan Tested-by: Peter Newman Tested-by: Babu Moger Tested-by: Carl Worth # arm64 Link: https://lore.kernel.org/r/20240213184438.16675-25-james.morse@arm.com Signed-off-by: Borislav Petkov (AMD)

x86/resctrl: Add CPU offline callback for resctrl work

2024-02-16T18:18:33+00:00

The resctrl architecture specific code may need to free a domain when a CPU goes offline, it also needs to reset the CPUs PQR_ASSOC register. Amongst other things, the resctrl filesystem code needs to clear this CPU from the cpu_mask of any control and monitor groups. Currently, this is all done in core.c and called from resctrl_offline_cpu(), making the split between architecture and filesystem code unclear. Move the filesystem work to remove the CPU from the control and monitor groups into a filesystem helper called resctrl_offline_cpu(), and rename the one in core.c resctrl_arch_offline_cpu(). Signed-off-by: James Morse Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Shaopeng Tan Reviewed-by: Reinette Chatre Reviewed-by: Babu Moger Tested-by: Shaopeng Tan Tested-by: Peter Newman Tested-by: Babu Moger Tested-by: Carl Worth # arm64 Link: https://lore.kernel.org/r/20240213184438.16675-23-james.morse@arm.com Signed-off-by: Borislav Petkov (AMD)

x86/resctrl: Allow overflow/limbo handlers to be scheduled on any-but CPU

2024-02-16T18:18:33+00:00

When a CPU is taken offline resctrl may need to move the overflow or limbo handlers to run on a different CPU. Once the offline callbacks have been split, cqm_setup_limbo_handler() will be called while the CPU that is going offline is still present in the CPU mask. Pass the CPU to exclude to cqm_setup_limbo_handler() and mbm_setup_overflow_handler(). These functions can use a variant of cpumask_any_but() when selecting the CPU. -1 is used to indicate no CPUs need excluding. Signed-off-by: James Morse Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Shaopeng Tan Reviewed-by: Babu Moger Reviewed-by: Reinette Chatre Tested-by: Shaopeng Tan Tested-by: Peter Newman Tested-by: Babu Moger Tested-by: Carl Worth # arm64 Link: https://lore.kernel.org/r/20240213184438.16675-22-james.morse@arm.com Signed-off-by: Borislav Petkov (AMD)