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-rw-r--r--arch/x86/kernel/cpu/intel_rdt.c32
-rw-r--r--arch/x86/kernel/cpu/intel_rdt.h6
-rw-r--r--arch/x86/kernel/cpu/intel_rdt_monitor.c213
3 files changed, 251 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/intel_rdt.c b/arch/x86/kernel/cpu/intel_rdt.c
index cb520dd73bc8..d30830a8eafd 100644
--- a/arch/x86/kernel/cpu/intel_rdt.c
+++ b/arch/x86/kernel/cpu/intel_rdt.c
@@ -320,6 +320,19 @@ cat_wrmsr(struct rdt_domain *d, struct msr_param *m, struct rdt_resource *r)
wrmsrl(r->msr_base + cbm_idx(r, i), d->ctrl_val[i]);
}
+struct rdt_domain *get_domain_from_cpu(int cpu, struct rdt_resource *r)
+{
+ struct rdt_domain *d;
+
+ list_for_each_entry(d, &r->domains, list) {
+ /* Find the domain that contains this CPU */
+ if (cpumask_test_cpu(cpu, &d->cpu_mask))
+ return d;
+ }
+
+ return NULL;
+}
+
void rdt_ctrl_update(void *arg)
{
struct msr_param *m = arg;
@@ -397,6 +410,19 @@ static int domain_setup_ctrlval(struct rdt_resource *r, struct rdt_domain *d)
return 0;
}
+static int domain_setup_mon_state(struct rdt_resource *r, struct rdt_domain *d)
+{
+ if (is_llc_occupancy_enabled()) {
+ d->rmid_busy_llc = kcalloc(BITS_TO_LONGS(r->num_rmid),
+ sizeof(unsigned long),
+ GFP_KERNEL);
+ if (!d->rmid_busy_llc)
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
/*
* domain_add_cpu - Add a cpu to a resource's domain list.
*
@@ -438,6 +464,11 @@ static void domain_add_cpu(int cpu, struct rdt_resource *r)
return;
}
+ if (r->mon_capable && domain_setup_mon_state(r, d)) {
+ kfree(d);
+ return;
+ }
+
cpumask_set_cpu(cpu, &d->cpu_mask);
list_add_tail(&d->list, add_pos);
}
@@ -456,6 +487,7 @@ static void domain_remove_cpu(int cpu, struct rdt_resource *r)
cpumask_clear_cpu(cpu, &d->cpu_mask);
if (cpumask_empty(&d->cpu_mask)) {
kfree(d->ctrl_val);
+ kfree(d->rmid_busy_llc);
list_del(&d->list);
kfree(d);
}
diff --git a/arch/x86/kernel/cpu/intel_rdt.h b/arch/x86/kernel/cpu/intel_rdt.h
index 993ab9d678bc..35bf8eb8437c 100644
--- a/arch/x86/kernel/cpu/intel_rdt.h
+++ b/arch/x86/kernel/cpu/intel_rdt.h
@@ -19,6 +19,8 @@
#define QOS_L3_OCCUP_EVENT_ID 0x01
#define QOS_L3_MBM_TOTAL_EVENT_ID 0x02
#define QOS_L3_MBM_LOCAL_EVENT_ID 0x03
+#define RMID_VAL_ERROR BIT_ULL(63)
+#define RMID_VAL_UNAVAIL BIT_ULL(62)
/**
* struct mon_evt - Entry in the event list of a resource
@@ -98,6 +100,8 @@ struct rftype {
* @list: all instances of this resource
* @id: unique id for this instance
* @cpu_mask: which cpus share this resource
+ * @rmid_busy_llc:
+ * bitmap of which limbo RMIDs are above threshold
* @ctrl_val: array of cache or mem ctrl values (indexed by CLOSID)
* @new_ctrl: new ctrl value to be loaded
* @have_new_ctrl: did user provide new_ctrl for this domain
@@ -106,6 +110,7 @@ struct rdt_domain {
struct list_head list;
int id;
struct cpumask cpu_mask;
+ unsigned long *rmid_busy_llc;
u32 *ctrl_val;
u32 new_ctrl;
bool have_new_ctrl;
@@ -282,6 +287,7 @@ ssize_t rdtgroup_schemata_write(struct kernfs_open_file *of,
char *buf, size_t nbytes, loff_t off);
int rdtgroup_schemata_show(struct kernfs_open_file *of,
struct seq_file *s, void *v);
+struct rdt_domain *get_domain_from_cpu(int cpu, struct rdt_resource *r);
int rdt_get_mon_l3_config(struct rdt_resource *r);
#endif /* _ASM_X86_INTEL_RDT_H */
diff --git a/arch/x86/kernel/cpu/intel_rdt_monitor.c b/arch/x86/kernel/cpu/intel_rdt_monitor.c
index f6d43c3eba4e..b6732c51829b 100644
--- a/arch/x86/kernel/cpu/intel_rdt_monitor.c
+++ b/arch/x86/kernel/cpu/intel_rdt_monitor.c
@@ -28,8 +28,12 @@
#include <asm/cpu_device_id.h>
#include "intel_rdt.h"
+#define MSR_IA32_QM_CTR 0x0c8e
+#define MSR_IA32_QM_EVTSEL 0x0c8d
+
struct rmid_entry {
u32 rmid;
+ atomic_t busy;
struct list_head list;
};
@@ -81,6 +85,215 @@ static inline struct rmid_entry *__rmid_entry(u32 rmid)
return entry;
}
+static u64 __rmid_read(u32 rmid, u32 eventid)
+{
+ u64 val;
+
+ /*
+ * As per the SDM, when IA32_QM_EVTSEL.EvtID (bits 7:0) is configured
+ * with a valid event code for supported resource type and the bits
+ * IA32_QM_EVTSEL.RMID (bits 41:32) are configured with valid RMID,
+ * IA32_QM_CTR.data (bits 61:0) reports the monitored data.
+ * IA32_QM_CTR.Error (bit 63) and IA32_QM_CTR.Unavailable (bit 62)
+ * are error bits.
+ */
+ wrmsr(MSR_IA32_QM_EVTSEL, eventid, rmid);
+ rdmsrl(MSR_IA32_QM_CTR, val);
+
+ return val;
+}
+
+/*
+ * Walk the limbo list looking at any RMIDs that are flagged in the
+ * domain rmid_busy_llc bitmap as busy. If the reported LLC occupancy
+ * is below the threshold clear the busy bit and decrement the count.
+ * If the busy count gets to zero on an RMID we stop looking.
+ * This can be called from an IPI.
+ * We need an atomic for the busy count because multiple CPUs may check
+ * the same RMID at the same time.
+ */
+static bool __check_limbo(struct rdt_domain *d)
+{
+ struct rmid_entry *entry;
+ u64 val;
+
+ list_for_each_entry(entry, &rmid_limbo_lru, list) {
+ if (!test_bit(entry->rmid, d->rmid_busy_llc))
+ continue;
+ val = __rmid_read(entry->rmid, QOS_L3_OCCUP_EVENT_ID);
+ if (val <= intel_cqm_threshold) {
+ clear_bit(entry->rmid, d->rmid_busy_llc);
+ if (atomic_dec_and_test(&entry->busy))
+ return true;
+ }
+ }
+ return false;
+}
+
+static void check_limbo(void *arg)
+{
+ struct rdt_domain *d;
+
+ d = get_domain_from_cpu(smp_processor_id(),
+ &rdt_resources_all[RDT_RESOURCE_L3]);
+
+ if (d)
+ __check_limbo(d);
+}
+
+static bool has_busy_rmid(struct rdt_resource *r, struct rdt_domain *d)
+{
+ return find_first_bit(d->rmid_busy_llc, r->num_rmid) != r->num_rmid;
+}
+
+/*
+ * Scan the limbo list and move all entries that are below the
+ * intel_cqm_threshold to the free list.
+ * Return "true" if the limbo list is empty, "false" if there are
+ * still some RMIDs there.
+ */
+static bool try_freeing_limbo_rmid(void)
+{
+ struct rmid_entry *entry, *tmp;
+ struct rdt_resource *r;
+ cpumask_var_t cpu_mask;
+ struct rdt_domain *d;
+ bool ret = true;
+ int cpu;
+
+ if (list_empty(&rmid_limbo_lru))
+ return ret;
+
+ r = &rdt_resources_all[RDT_RESOURCE_L3];
+
+ cpu = get_cpu();
+
+ /*
+ * First see if we can free up an RMID by checking busy values
+ * on the local package.
+ */
+ d = get_domain_from_cpu(cpu, r);
+ if (d && has_busy_rmid(r, d) && __check_limbo(d)) {
+ list_for_each_entry_safe(entry, tmp, &rmid_limbo_lru, list) {
+ if (atomic_read(&entry->busy) == 0) {
+ list_del(&entry->list);
+ list_add_tail(&entry->list, &rmid_free_lru);
+ goto done;
+ }
+ }
+ }
+
+ if (!zalloc_cpumask_var(&cpu_mask, GFP_KERNEL)) {
+ ret = false;
+ goto done;
+ }
+
+ /*
+ * Build a mask of other domains that have busy RMIDs
+ */
+ list_for_each_entry(d, &r->domains, list) {
+ if (!cpumask_test_cpu(cpu, &d->cpu_mask) &&
+ has_busy_rmid(r, d))
+ cpumask_set_cpu(cpumask_any(&d->cpu_mask), cpu_mask);
+ }
+ if (cpumask_empty(cpu_mask)) {
+ ret = false;
+ goto free_mask;
+ }
+
+ /*
+ * Scan domains with busy RMIDs to check if they still are busy
+ */
+ on_each_cpu_mask(cpu_mask, check_limbo, NULL, true);
+
+ /* Walk limbo list moving all free RMIDs to the &rmid_free_lru list */
+ list_for_each_entry_safe(entry, tmp, &rmid_limbo_lru, list) {
+ if (atomic_read(&entry->busy) != 0) {
+ ret = false;
+ continue;
+ }
+ list_del(&entry->list);
+ list_add_tail(&entry->list, &rmid_free_lru);
+ }
+
+free_mask:
+ free_cpumask_var(cpu_mask);
+done:
+ put_cpu();
+ return ret;
+}
+
+/*
+ * As of now the RMIDs allocation is global.
+ * However we keep track of which packages the RMIDs
+ * are used to optimize the limbo list management.
+ */
+int alloc_rmid(void)
+{
+ struct rmid_entry *entry;
+ bool ret;
+
+ lockdep_assert_held(&rdtgroup_mutex);
+
+ if (list_empty(&rmid_free_lru)) {
+ ret = try_freeing_limbo_rmid();
+ if (list_empty(&rmid_free_lru))
+ return ret ? -ENOSPC : -EBUSY;
+ }
+
+ entry = list_first_entry(&rmid_free_lru,
+ struct rmid_entry, list);
+ list_del(&entry->list);
+
+ return entry->rmid;
+}
+
+static void add_rmid_to_limbo(struct rmid_entry *entry)
+{
+ struct rdt_resource *r;
+ struct rdt_domain *d;
+ int cpu, nbusy = 0;
+ u64 val;
+
+ r = &rdt_resources_all[RDT_RESOURCE_L3];
+
+ cpu = get_cpu();
+ list_for_each_entry(d, &r->domains, list) {
+ if (cpumask_test_cpu(cpu, &d->cpu_mask)) {
+ val = __rmid_read(entry->rmid, QOS_L3_OCCUP_EVENT_ID);
+ if (val <= intel_cqm_threshold)
+ continue;
+ }
+ set_bit(entry->rmid, d->rmid_busy_llc);
+ nbusy++;
+ }
+ put_cpu();
+
+ if (nbusy) {
+ atomic_set(&entry->busy, nbusy);
+ list_add_tail(&entry->list, &rmid_limbo_lru);
+ } else {
+ list_add_tail(&entry->list, &rmid_free_lru);
+ }
+}
+
+void free_rmid(u32 rmid)
+{
+ struct rmid_entry *entry;
+
+ if (!rmid)
+ return;
+
+ lockdep_assert_held(&rdtgroup_mutex);
+
+ entry = __rmid_entry(rmid);
+
+ if (is_llc_occupancy_enabled())
+ add_rmid_to_limbo(entry);
+ else
+ list_add_tail(&entry->list, &rmid_free_lru);
+}
+
static int dom_data_init(struct rdt_resource *r)
{
struct rmid_entry *entry = NULL;
generated by cgit (git 2.34.1) at 2024-06-26 01:26:31 +0000