From 46637d4570e108d1f6721cfa2cca1d078882761a Mon Sep 17 00:00:00 2001 From: Reinette Chatre Date: Tue, 5 May 2020 15:36:16 -0700 Subject: x86/resctrl: Maintain MBM counter width per resource The original Memory Bandwidth Monitoring (MBM) architectural definition defines counters of up to 62 bits in the IA32_QM_CTR MSR, and the first-generation MBM implementation uses 24 bit counters. Software is required to poll at 1 second or faster to ensure that data is retrieved before a counter rollover occurs more than once under worst conditions. As system bandwidths scale the software requirement is maintained with the introduction of a per-resource enumerable MBM counter width. In preparation for supporting hardware with an enumerable MBM counter width the current globally static MBM counter width is moved to a per-resource MBM counter width. Currently initialized to 24 always to result in no functional change. In essence there is one function, mbm_overflow_count() that needs to know the counter width to handle rollovers. The static value used within mbm_overflow_count() will be replaced with a value discovered from the hardware. Support for learning the MBM counter width from hardware is added in the change that follows. Signed-off-by: Reinette Chatre Signed-off-by: Borislav Petkov Link: https://lkml.kernel.org/r/e36743b9800f16ce600f86b89127391f61261f23.1588715690.git.reinette.chatre@intel.com --- arch/x86/kernel/cpu/resctrl/ctrlmondata.c | 8 +++++--- arch/x86/kernel/cpu/resctrl/internal.h | 7 +++++-- arch/x86/kernel/cpu/resctrl/monitor.c | 21 +++++++++++++-------- arch/x86/kernel/cpu/resctrl/rdtgroup.c | 2 +- 4 files changed, 24 insertions(+), 14 deletions(-) diff --git a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c index 055c8613b531..934c8fb8a64a 100644 --- a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c +++ b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c @@ -495,14 +495,16 @@ int rdtgroup_schemata_show(struct kernfs_open_file *of, return ret; } -void mon_event_read(struct rmid_read *rr, struct rdt_domain *d, - struct rdtgroup *rdtgrp, int evtid, int first) +void mon_event_read(struct rmid_read *rr, struct rdt_resource *r, + struct rdt_domain *d, struct rdtgroup *rdtgrp, + int evtid, int first) { /* * setup the parameters to send to the IPI to read the data. */ rr->rgrp = rdtgrp; rr->evtid = evtid; + rr->r = r; rr->d = d; rr->val = 0; rr->first = first; @@ -539,7 +541,7 @@ int rdtgroup_mondata_show(struct seq_file *m, void *arg) goto out; } - mon_event_read(&rr, d, rdtgrp, evtid, false); + mon_event_read(&rr, r, d, rdtgrp, evtid, false); if (rr.val & RMID_VAL_ERROR) seq_puts(m, "Error\n"); diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h index 3dd13f3a8b23..58b002c31655 100644 --- a/arch/x86/kernel/cpu/resctrl/internal.h +++ b/arch/x86/kernel/cpu/resctrl/internal.h @@ -87,6 +87,7 @@ union mon_data_bits { struct rmid_read { struct rdtgroup *rgrp; + struct rdt_resource *r; struct rdt_domain *d; int evtid; bool first; @@ -460,6 +461,7 @@ struct rdt_resource { struct list_head evt_list; int num_rmid; unsigned int mon_scale; + unsigned int mbm_width; unsigned long fflags; }; @@ -587,8 +589,9 @@ void rmdir_mondata_subdir_allrdtgrp(struct rdt_resource *r, unsigned int dom_id); void mkdir_mondata_subdir_allrdtgrp(struct rdt_resource *r, struct rdt_domain *d); -void mon_event_read(struct rmid_read *rr, struct rdt_domain *d, - struct rdtgroup *rdtgrp, int evtid, int first); +void mon_event_read(struct rmid_read *rr, struct rdt_resource *r, + struct rdt_domain *d, struct rdtgroup *rdtgrp, + int evtid, int first); void mbm_setup_overflow_handler(struct rdt_domain *dom, unsigned long delay_ms); void mbm_handle_overflow(struct work_struct *work); diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c index 773124b0e18a..df964c03f6c6 100644 --- a/arch/x86/kernel/cpu/resctrl/monitor.c +++ b/arch/x86/kernel/cpu/resctrl/monitor.c @@ -214,9 +214,9 @@ void free_rmid(u32 rmid) list_add_tail(&entry->list, &rmid_free_lru); } -static u64 mbm_overflow_count(u64 prev_msr, u64 cur_msr) +static u64 mbm_overflow_count(u64 prev_msr, u64 cur_msr, unsigned int width) { - u64 shift = 64 - MBM_CNTR_WIDTH, chunks; + u64 shift = 64 - width, chunks; chunks = (cur_msr << shift) - (prev_msr << shift); return chunks >>= shift; @@ -256,7 +256,7 @@ static int __mon_event_count(u32 rmid, struct rmid_read *rr) return 0; } - chunks = mbm_overflow_count(m->prev_msr, tval); + chunks = mbm_overflow_count(m->prev_msr, tval, rr->r->mbm_width); m->chunks += chunks; m->prev_msr = tval; @@ -278,7 +278,7 @@ static void mbm_bw_count(u32 rmid, struct rmid_read *rr) if (tval & (RMID_VAL_ERROR | RMID_VAL_UNAVAIL)) return; - chunks = mbm_overflow_count(m->prev_bw_msr, tval); + chunks = mbm_overflow_count(m->prev_bw_msr, tval, rr->r->mbm_width); m->chunks_bw += chunks; m->chunks = m->chunks_bw; cur_bw = (chunks * r->mon_scale) >> 20; @@ -433,11 +433,12 @@ static void update_mba_bw(struct rdtgroup *rgrp, struct rdt_domain *dom_mbm) } } -static void mbm_update(struct rdt_domain *d, int rmid) +static void mbm_update(struct rdt_resource *r, struct rdt_domain *d, int rmid) { struct rmid_read rr; rr.first = false; + rr.r = r; rr.d = d; /* @@ -510,6 +511,7 @@ void mbm_handle_overflow(struct work_struct *work) struct rdtgroup *prgrp, *crgrp; int cpu = smp_processor_id(); struct list_head *head; + struct rdt_resource *r; struct rdt_domain *d; mutex_lock(&rdtgroup_mutex); @@ -517,16 +519,18 @@ void mbm_handle_overflow(struct work_struct *work) if (!static_branch_likely(&rdt_mon_enable_key)) goto out_unlock; - d = get_domain_from_cpu(cpu, &rdt_resources_all[RDT_RESOURCE_L3]); + r = &rdt_resources_all[RDT_RESOURCE_L3]; + + d = get_domain_from_cpu(cpu, r); if (!d) goto out_unlock; list_for_each_entry(prgrp, &rdt_all_groups, rdtgroup_list) { - mbm_update(d, prgrp->mon.rmid); + mbm_update(r, d, prgrp->mon.rmid); head = &prgrp->mon.crdtgrp_list; list_for_each_entry(crgrp, head, mon.crdtgrp_list) - mbm_update(d, crgrp->mon.rmid); + mbm_update(r, d, crgrp->mon.rmid); if (is_mba_sc(NULL)) update_mba_bw(prgrp, d); @@ -619,6 +623,7 @@ int rdt_get_mon_l3_config(struct rdt_resource *r) r->mon_scale = boot_cpu_data.x86_cache_occ_scale; r->num_rmid = boot_cpu_data.x86_cache_max_rmid + 1; + r->mbm_width = MBM_CNTR_WIDTH; /* * A reasonable upper limit on the max threshold is the number diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c index 6276ae015945..d7cb5ab0d1f0 100644 --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c @@ -2472,7 +2472,7 @@ static int mkdir_mondata_subdir(struct kernfs_node *parent_kn, goto out_destroy; if (is_mbm_event(mevt->evtid)) - mon_event_read(&rr, d, prgrp, mevt->evtid, true); + mon_event_read(&rr, r, d, prgrp, mevt->evtid, true); } kernfs_activate(kn); return 0; -- cgit v1.2.3