From 594902c986e269660302f09df9ec4bf1cf017b77 Mon Sep 17 00:00:00 2001 From: Qinyun Tan Date: Sat, 31 May 2025 02:20:53 +0800 Subject: x86,fs/resctrl: Remove inappropriate references to cacheinfo in the resctrl subsystem 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. Fixes: 328ea68874642 ("x86/resctrl: Prepare for new Sub-NUMA Cluster (SNC) monitor files") Signed-off-by: Qinyun Tan Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Reinette Chatre Tested-by: Tony Luck Link: https://lore.kernel.org/20250530182053.37502-2-qinyuntan@linux.alibaba.com --- include/linux/resctrl.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'include/linux/resctrl.h') diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h index 9ba771f2ddea..6fb4894b8cfd 100644 --- a/include/linux/resctrl.h +++ b/include/linux/resctrl.h @@ -159,7 +159,7 @@ struct rdt_ctrl_domain { /** * struct rdt_mon_domain - group of CPUs sharing a resctrl monitor resource * @hdr: common header for different domain types - * @ci: cache info for this domain + * @ci_id: cache info id for this domain * @rmid_busy_llc: bitmap of which limbo RMIDs are above threshold * @mbm_total: saved state for MBM total bandwidth * @mbm_local: saved state for MBM local bandwidth @@ -170,7 +170,7 @@ struct rdt_ctrl_domain { */ struct rdt_mon_domain { struct rdt_domain_hdr hdr; - struct cacheinfo *ci; + unsigned int ci_id; unsigned long *rmid_busy_llc; struct mbm_state *mbm_total; struct mbm_state *mbm_local; -- cgit v1.2.3