x86,fs/resctrl: Remove inappropriate references to cacheinfo in the r… #89
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…esctrl subsystem commit 594902c986e269660302f09df9ec4bf1cf017b77 upstream. In the resctrl subsystem's Sub-NUMA Cluster (SNC) mode, the rdt_mon_domain structure representing a NUMA node relies on the cacheinfo interface (rdt_mon_domain::ci) to store L3 cache information (e.g., shared_cpu_map) for monitoring. The L3 cache information of a SNC NUMA node determines which domains are summed for the "top level" L3-scoped events. rdt_mon_domain::ci is initialized using the first online CPU of a NUMA node. When this CPU goes offline, its shared_cpu_map is cleared to contain only the offline CPU itself. Subsequently, attempting to read counters via smp_call_on_cpu(offline_cpu) fails (and error ignored), returning zero values for "top-level events" without any error indication. Replace the cacheinfo references in struct rdt_mon_domain and struct rmid_read with the cacheinfo ID (a unique identifier for the L3 cache). rdt_domain_hdr::cpu_mask contains the online CPUs associated with that domain. When reading "top-level events", select a CPU from rdt_domain_hdr::cpu_mask and utilize its L3 shared_cpu_map to determine valid CPUs for reading RMID counter via the MSR interface. Considering all CPUs associated with the L3 cache improves the chances of picking a housekeeping CPU on which the counter reading work can be queued, avoiding an unnecessary IPI. Intel-SIG: commit 594902c986e x86,fs/resctrl: Remove inappropriate references to cacheinfo in the resctrl subsystem backport to RDT driver for CWF Fixes: 328ea68 ("x86/resctrl: Prepare for new Sub-NUMA Cluster (SNC) monitor files") Signed-off-by: Qinyun Tan <qinyuntan@linux.alibaba.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Tested-by: Tony Luck <tony.luck@intel.com> Link: https://lore.kernel.org/20250530182053.37502-2-qinyuntan@linux.alibaba.com Signed-off-by: Kui Wen <kui.wen@intel.com>
beckwen
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Hello, please also backport commit d2e1b84c5141ff2ad465279acfc3cf943c960b78("fs/resctrl: Eliminate false positive lockdep warning when reading SNC counters") which is a fix patch to commit 594902c98 |
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Please ensure that the Date and author information of the patch are consistent with the content of the upstream patch: Author: Qinyun Tan qinyuntan@linux.alibaba.com |
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…esctrl subsystem
commit 594902c986e269660302f09df9ec4bf1cf017b77 upstream.
In the resctrl subsystem's Sub-NUMA Cluster (SNC) mode, the rdt_mon_domain structure representing a NUMA node relies on the cacheinfo interface (rdt_mon_domain::ci) to store L3 cache information (e.g., shared_cpu_map) for monitoring. The L3 cache information of a SNC NUMA node determines which domains are summed for the "top level" L3-scoped events.
rdt_mon_domain::ci is initialized using the first online CPU of a NUMA node. When this CPU goes offline, its shared_cpu_map is cleared to contain only the offline CPU itself. Subsequently, attempting to read counters via smp_call_on_cpu(offline_cpu) fails (and error ignored), returning zero values for "top-level events" without any error indication.
Replace the cacheinfo references in struct rdt_mon_domain and struct rmid_read with the cacheinfo ID (a unique identifier for the L3 cache).
rdt_domain_hdr::cpu_mask contains the online CPUs associated with that domain. When reading "top-level events", select a CPU from rdt_domain_hdr::cpu_mask and utilize its L3 shared_cpu_map to determine valid CPUs for reading RMID counter via the MSR interface.
Considering all CPUs associated with the L3 cache improves the chances of picking a housekeeping CPU on which the counter reading work can be queued, avoiding an unnecessary IPI.
Intel-SIG: commit 594902c986e
x86,fs/resctrl: Remove inappropriate references to cacheinfo in the resctrl subsystem backport to RDT driver for CWF
Test case: run the tool under kernel tools/testing/selftests/resctrl
./resctrl_tests
Fixes: 328ea68 ("x86/resctrl: Prepare for new Sub-NUMA Cluster (SNC) monitor files")
Reviewed-by: Reinette Chatre reinette.chatre@intel.com
Tested-by: Tony Luck tony.luck@intel.com
Link: https://lore.kernel.org/20250530182053.37502-2-qinyuntan@linux.alibaba.com