[PATCH v19 14/20] x86/resctrl: Fill out rmid_read structure for smp_call*() to read a counter

Tony Luck
2024-05-28T22:20:25Z

mon_event_read() fills out most fields of the struct rmid_read that is
passed via an smp_call*() function to a CPU that is part of the correct
domain to read the monitor counters.

The one exception is the sumdomains field that is set by the caller
(either rdtgroup_mondata_show() or mon_add_all_files()).

When rmid_read.sumdomains is false:
The domain field "d" specifies the only domain to read
CPU to execute is chosen from d->hdr.cpu_mask

When rmid_read.sumdomains is true:
The domain field is NULL.
The cache_info field indicates that all domains
that are part of that cache instance should be
summed.
CPU to execute is chosen from ci->shared_cpu_mask

Signed-off-by: Tony Luck <tony.luck@intel.com>
---
arch/x86/kernel/cpu/resctrl/ctrlmondata.c | 28 ++++++++++++++++++-----
1 file changed, 22 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
index 3b9383612c35..4e394400e575 100644
--- a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
+++ b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
@@ -517,6 +517,7 @@ void mon_event_read(struct rmid_read *rr, struct rdt_resource *r,
struct rdt_mon_domain *d, struct rdtgroup *rdtgrp,
int evtid, int first)
{
+ cpumask_t *cpumask;
int cpu;

/* When picking a CPU from cpu_mask, ensure it can't race with cpuhp */
@@ -537,7 +538,8 @@ void mon_event_read(struct rmid_read *rr, struct rdt_resource *r,
return;
}

- cpu = cpumask_any_housekeeping(&d->hdr.cpu_mask, RESCTRL_PICK_ANY_CPU);
+ cpumask = rr->sumdomains ? &rr->ci->shared_cpu_map : &d->hdr.cpu_mask;
+ cpu = cpumask_any_housekeeping(cpumask, RESCTRL_PICK_ANY_CPU);

/*
* cpumask_any_housekeeping() prefers housekeeping CPUs, but
@@ -546,7 +548,7 @@ void mon_event_read(struct rmid_read *rr, struct rdt_resource *r,
* counters on some platforms if its called in IRQ context.
*/
if (tick_nohz_full_cpu(cpu))
- smp_call_function_any(&d->hdr.cpu_mask, mon_event_count, rr, 1);
+ smp_call_function_any(cpumask, mon_event_count, rr, 1);
else
smp_call_on_cpu(cpu, smp_mon_event_count, rr, false);

@@ -575,15 +577,29 @@ int rdtgroup_mondata_show(struct seq_file *m, void *arg)
resid = md.u.rid;
domid = md.u.domid;
evtid = md.u.evtid;
-
+ rr.sumdomains = md.u.sum;
r = &rdt_resources_all[resid].r_resctrl;
- hdr = rdt_find_domain(&r->mon_domains, domid, NULL);
- if (!hdr || WARN_ON_ONCE(hdr->type != RESCTRL_MON_DOMAIN)) {
+
+ if (rr.sumdomains) {
+ list_for_each_entry(d, &r->mon_domains, hdr.list) {
+ if (d->ci->id == domid) {
+ rr.ci = d->ci;
+ d = NULL;
+ goto got_cacheinfo;
+ }
+ }
ret = -ENOENT;
goto out;
+ } else {
+ hdr = rdt_find_domain(&r->mon_domains, domid, NULL);
+ if (!hdr || WARN_ON_ONCE(hdr->type != RESCTRL_MON_DOMAIN)) {
+ ret = -ENOENT;
+ goto out;
+ }
+ d = container_of(hdr, struct rdt_mon_domain, hdr);
}
- d = container_of(hdr, struct rdt_mon_domain, hdr);

+got_cacheinfo:
mon_event_read(&rr, r, d, rdtgrp, evtid, false);

if (rr.err == -EIO)
--
2.45.0