static DEFINE_MUTEX(memory_tier_lock);
static LIST_HEAD(memory_tiers);
static struct node_memory_type_map node_memory_types[MAX_NUMNODES];
-static struct memory_dev_type *default_dram_type;
+struct memory_dev_type *default_dram_type;
static struct bus_type memory_tier_subsys = {
.name = "memory_tiering",
static BLOCKING_NOTIFIER_HEAD(mt_adistance_algorithms);
+static bool default_dram_perf_error;
+static struct node_hmem_attrs default_dram_perf;
+static int default_dram_perf_ref_nid = NUMA_NO_NODE;
+static const char *default_dram_perf_ref_source;
+
static inline struct memory_tier *to_memory_tier(struct device *device)
{
return container_of(device, struct memory_tier, dev);
}
EXPORT_SYMBOL_GPL(clear_node_memory_type);
+static void dump_hmem_attrs(struct node_hmem_attrs *attrs, const char *prefix)
+{
+ pr_info(
+"%sread_latency: %u, write_latency: %u, read_bandwidth: %u, write_bandwidth: %u\n",
+ prefix, attrs->read_latency, attrs->write_latency,
+ attrs->read_bandwidth, attrs->write_bandwidth);
+}
+
+int mt_set_default_dram_perf(int nid, struct node_hmem_attrs *perf,
+ const char *source)
+{
+ int rc = 0;
+
+ mutex_lock(&memory_tier_lock);
+ if (default_dram_perf_error) {
+ rc = -EIO;
+ goto out;
+ }
+
+ if (perf->read_latency + perf->write_latency == 0 ||
+ perf->read_bandwidth + perf->write_bandwidth == 0) {
+ rc = -EINVAL;
+ goto out;
+ }
+
+ if (default_dram_perf_ref_nid == NUMA_NO_NODE) {
+ default_dram_perf = *perf;
+ default_dram_perf_ref_nid = nid;
+ default_dram_perf_ref_source = kstrdup(source, GFP_KERNEL);
+ goto out;
+ }
+
+ /*
+ * The performance of all default DRAM nodes is expected to be
+ * same (that is, the variation is less than 10%). And it
+ * will be used as base to calculate the abstract distance of
+ * other memory nodes.
+ */
+ if (abs(perf->read_latency - default_dram_perf.read_latency) * 10 >
+ default_dram_perf.read_latency ||
+ abs(perf->write_latency - default_dram_perf.write_latency) * 10 >
+ default_dram_perf.write_latency ||
+ abs(perf->read_bandwidth - default_dram_perf.read_bandwidth) * 10 >
+ default_dram_perf.read_bandwidth ||
+ abs(perf->write_bandwidth - default_dram_perf.write_bandwidth) * 10 >
+ default_dram_perf.write_bandwidth) {
+ pr_info(
+"memory-tiers: the performance of DRAM node %d mismatches that of the reference\n"
+"DRAM node %d.\n", nid, default_dram_perf_ref_nid);
+ pr_info(" performance of reference DRAM node %d:\n",
+ default_dram_perf_ref_nid);
+ dump_hmem_attrs(&default_dram_perf, " ");
+ pr_info(" performance of DRAM node %d:\n", nid);
+ dump_hmem_attrs(perf, " ");
+ pr_info(
+" disable default DRAM node performance based abstract distance algorithm.\n");
+ default_dram_perf_error = true;
+ rc = -EINVAL;
+ }
+
+out:
+ mutex_unlock(&memory_tier_lock);
+ return rc;
+}
+
+int mt_perf_to_adistance(struct node_hmem_attrs *perf, int *adist)
+{
+ if (default_dram_perf_error)
+ return -EIO;
+
+ if (default_dram_perf_ref_nid == NUMA_NO_NODE)
+ return -ENOENT;
+
+ if (perf->read_latency + perf->write_latency == 0 ||
+ perf->read_bandwidth + perf->write_bandwidth == 0)
+ return -EINVAL;
+
+ mutex_lock(&memory_tier_lock);
+ /*
+ * The abstract distance of a memory node is in direct proportion to
+ * its memory latency (read + write) and inversely proportional to its
+ * memory bandwidth (read + write). The abstract distance, memory
+ * latency, and memory bandwidth of the default DRAM nodes are used as
+ * the base.
+ */
+ *adist = MEMTIER_ADISTANCE_DRAM *
+ (perf->read_latency + perf->write_latency) /
+ (default_dram_perf.read_latency + default_dram_perf.write_latency) *
+ (default_dram_perf.read_bandwidth + default_dram_perf.write_bandwidth) /
+ (perf->read_bandwidth + perf->write_bandwidth);
+ mutex_unlock(&memory_tier_lock);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(mt_perf_to_adistance);
+
/**
* register_mt_adistance_algorithm() - Register memory tiering abstract distance algorithm
* @nb: The notifier block which describe the algorithm