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

[Tony Luck]

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@xxxxxxxxx>
---
 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