From: Qinyun Tan Date: Fri, 30 May 2025 18:20:53 +0000 (+0800) Subject: x86,fs/resctrl: Remove inappropriate references to cacheinfo in the resctrl subsystem X-Git-Tag: v6.16-rc3~2^2~4 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=594902c986e269660302f09df9ec4bf1cf017b77;p=thirdparty%2Fkernel%2Flinux.git 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 --- diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c index 7109cbfcad4fd..187d527ef73b6 100644 --- a/arch/x86/kernel/cpu/resctrl/core.c +++ b/arch/x86/kernel/cpu/resctrl/core.c @@ -498,6 +498,7 @@ static void domain_add_cpu_mon(int cpu, struct rdt_resource *r) struct rdt_hw_mon_domain *hw_dom; struct rdt_domain_hdr *hdr; struct rdt_mon_domain *d; + struct cacheinfo *ci; int err; lockdep_assert_held(&domain_list_lock); @@ -525,12 +526,13 @@ static void domain_add_cpu_mon(int cpu, struct rdt_resource *r) d = &hw_dom->d_resctrl; d->hdr.id = id; d->hdr.type = RESCTRL_MON_DOMAIN; - d->ci = get_cpu_cacheinfo_level(cpu, RESCTRL_L3_CACHE); - if (!d->ci) { + ci = get_cpu_cacheinfo_level(cpu, RESCTRL_L3_CACHE); + if (!ci) { pr_warn_once("Can't find L3 cache for CPU:%d resource %s\n", cpu, r->name); mon_domain_free(hw_dom); return; } + d->ci_id = ci->id; cpumask_set_cpu(cpu, &d->hdr.cpu_mask); arch_mon_domain_online(r, d); diff --git a/fs/resctrl/ctrlmondata.c b/fs/resctrl/ctrlmondata.c index 6ed2dfd4dbbd9..d98e0d2de09fd 100644 --- a/fs/resctrl/ctrlmondata.c +++ b/fs/resctrl/ctrlmondata.c @@ -594,9 +594,10 @@ int rdtgroup_mondata_show(struct seq_file *m, void *arg) struct rmid_read rr = {0}; struct rdt_mon_domain *d; struct rdtgroup *rdtgrp; + int domid, cpu, ret = 0; struct rdt_resource *r; + struct cacheinfo *ci; struct mon_data *md; - int domid, ret = 0; rdtgrp = rdtgroup_kn_lock_live(of->kn); if (!rdtgrp) { @@ -623,10 +624,14 @@ int rdtgroup_mondata_show(struct seq_file *m, void *arg) * one that matches this cache id. */ list_for_each_entry(d, &r->mon_domains, hdr.list) { - if (d->ci->id == domid) { - rr.ci = d->ci; + if (d->ci_id == domid) { + rr.ci_id = d->ci_id; + cpu = cpumask_any(&d->hdr.cpu_mask); + ci = get_cpu_cacheinfo_level(cpu, RESCTRL_L3_CACHE); + if (!ci) + continue; mon_event_read(&rr, r, NULL, rdtgrp, - &d->ci->shared_cpu_map, evtid, false); + &ci->shared_cpu_map, evtid, false); goto checkresult; } } diff --git a/fs/resctrl/internal.h b/fs/resctrl/internal.h index 9a8cf6f11151d..0a1eedba2b03a 100644 --- a/fs/resctrl/internal.h +++ b/fs/resctrl/internal.h @@ -98,7 +98,7 @@ struct mon_data { * domains in @r sharing L3 @ci.id * @evtid: Which monitor event to read. * @first: Initialize MBM counter when true. - * @ci: Cacheinfo for L3. Only set when @d is NULL. Used when summing domains. + * @ci_id: Cacheinfo id for L3. Only set when @d is NULL. Used when summing domains. * @err: Error encountered when reading counter. * @val: Returned value of event counter. If @rgrp is a parent resource group, * @val includes the sum of event counts from its child resource groups. @@ -112,7 +112,7 @@ struct rmid_read { struct rdt_mon_domain *d; enum resctrl_event_id evtid; bool first; - struct cacheinfo *ci; + unsigned int ci_id; int err; u64 val; void *arch_mon_ctx; diff --git a/fs/resctrl/monitor.c b/fs/resctrl/monitor.c index bde2801289d35..f5637855c3aca 100644 --- a/fs/resctrl/monitor.c +++ b/fs/resctrl/monitor.c @@ -361,6 +361,7 @@ static int __mon_event_count(u32 closid, u32 rmid, struct rmid_read *rr) { int cpu = smp_processor_id(); struct rdt_mon_domain *d; + struct cacheinfo *ci; struct mbm_state *m; int err, ret; u64 tval = 0; @@ -388,7 +389,8 @@ static int __mon_event_count(u32 closid, u32 rmid, struct rmid_read *rr) } /* Summing domains that share a cache, must be on a CPU for that cache. */ - if (!cpumask_test_cpu(cpu, &rr->ci->shared_cpu_map)) + ci = get_cpu_cacheinfo_level(cpu, RESCTRL_L3_CACHE); + if (!ci || ci->id != rr->ci_id) return -EINVAL; /* @@ -400,7 +402,7 @@ static int __mon_event_count(u32 closid, u32 rmid, struct rmid_read *rr) */ ret = -EINVAL; list_for_each_entry(d, &rr->r->mon_domains, hdr.list) { - if (d->ci->id != rr->ci->id) + if (d->ci_id != rr->ci_id) continue; err = resctrl_arch_rmid_read(rr->r, d, closid, rmid, rr->evtid, &tval, rr->arch_mon_ctx); diff --git a/fs/resctrl/rdtgroup.c b/fs/resctrl/rdtgroup.c index 1beb124e25f6f..77d08229d8550 100644 --- a/fs/resctrl/rdtgroup.c +++ b/fs/resctrl/rdtgroup.c @@ -3036,7 +3036,7 @@ static void rmdir_mondata_subdir_allrdtgrp(struct rdt_resource *r, char name[32]; snc_mode = r->mon_scope == RESCTRL_L3_NODE; - sprintf(name, "mon_%s_%02d", r->name, snc_mode ? d->ci->id : d->hdr.id); + sprintf(name, "mon_%s_%02d", r->name, snc_mode ? d->ci_id : d->hdr.id); if (snc_mode) sprintf(subname, "mon_sub_%s_%02d", r->name, d->hdr.id); @@ -3061,7 +3061,7 @@ static int mon_add_all_files(struct kernfs_node *kn, struct rdt_mon_domain *d, return -EPERM; list_for_each_entry(mevt, &r->evt_list, list) { - domid = do_sum ? d->ci->id : d->hdr.id; + domid = do_sum ? d->ci_id : d->hdr.id; priv = mon_get_kn_priv(r->rid, domid, mevt, do_sum); if (WARN_ON_ONCE(!priv)) return -EINVAL; @@ -3089,7 +3089,7 @@ static int mkdir_mondata_subdir(struct kernfs_node *parent_kn, lockdep_assert_held(&rdtgroup_mutex); snc_mode = r->mon_scope == RESCTRL_L3_NODE; - sprintf(name, "mon_%s_%02d", r->name, snc_mode ? d->ci->id : d->hdr.id); + sprintf(name, "mon_%s_%02d", r->name, snc_mode ? d->ci_id : d->hdr.id); kn = kernfs_find_and_get(parent_kn, name); if (kn) { /* diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h index 9ba771f2ddead..6fb4894b8cfd1 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;