1 files changed, 50 insertions, 1 deletions

diff --git a/drivers/base/cacheinfo.c b/drivers/base/cacheinfo.c
index cbae8be1fe..f1e79263fe 100644
--- a/drivers/base/cacheinfo.c
+++ b/drivers/base/cacheinfo.c
@@ -898,6 +898,48 @@ err:
 	return rc;
 }
 
+/*
+ * Calculate the size of the per-CPU data cache slice.  This can be
+ * used to estimate the size of the data cache slice that can be used
+ * by one CPU under ideal circumstances.  UNIFIED caches are counted
+ * in addition to DATA caches.  So, please consider code cache usage
+ * when use the result.
+ *
+ * Because the cache inclusive/non-inclusive information isn't
+ * available, we just use the size of the per-CPU slice of LLC to make
+ * the result more predictable across architectures.
+ */
+static void update_per_cpu_data_slice_size_cpu(unsigned int cpu)
+{
+	struct cpu_cacheinfo *ci;
+	struct cacheinfo *llc;
+	unsigned int nr_shared;
+
+	if (!last_level_cache_is_valid(cpu))
+		return;
+
+	ci = ci_cacheinfo(cpu);
+	llc = per_cpu_cacheinfo_idx(cpu, cache_leaves(cpu) - 1);
+
+	if (llc->type != CACHE_TYPE_DATA && llc->type != CACHE_TYPE_UNIFIED)
+		return;
+
+	nr_shared = cpumask_weight(&llc->shared_cpu_map);
+	if (nr_shared)
+		ci->per_cpu_data_slice_size = llc->size / nr_shared;
+}
+
+static void update_per_cpu_data_slice_size(bool cpu_online, unsigned int cpu)
+{
+	unsigned int icpu;
+
+	for_each_online_cpu(icpu) {
+		if (!cpu_online && icpu == cpu)
+			continue;
+		update_per_cpu_data_slice_size_cpu(icpu);
+	}
+}
+
 static int cacheinfo_cpu_online(unsigned int cpu)
 {
 	int rc = detect_cache_attributes(cpu);
@@ -906,7 +948,12 @@ static int cacheinfo_cpu_online(unsigned int cpu)
 		return rc;
 	rc = cache_add_dev(cpu);
 	if (rc)
-		free_cache_attributes(cpu);
+		goto err;
+	update_per_cpu_data_slice_size(true, cpu);
+	setup_pcp_cacheinfo();
+	return 0;
+err:
+	free_cache_attributes(cpu);
 	return rc;
 }
 
@@ -916,6 +963,8 @@ static int cacheinfo_cpu_pre_down(unsigned int cpu)
 		cpu_cache_sysfs_exit(cpu);
 
 	free_cache_attributes(cpu);
+	update_per_cpu_data_slice_size(false, cpu);
+	setup_pcp_cacheinfo();
 	return 0;
 }