[RFC v1 1/2] mm/slab: add sheaves_enabled read-only sysfs file

[Harry Yoo <harry.yoo@oracle.com>]

For user-space tools like slabinfo, it is difficult to determine whether
a cache has sheaves enabled. Expose a read-only 'sheaves_enabled' sysfs
file to indicate whether sheaves are enabled for a given cache.

Signed-off-by: Harry Yoo <harry.yoo@oracle.com>
---
 mm/slub.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/mm/slub.c b/mm/slub.c
index b5ea66cbbe68..32db440a8b05 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -8504,6 +8504,15 @@ static ssize_t remote_node_defrag_ratio_store(struct kmem_cache *s,
 SLAB_ATTR(remote_node_defrag_ratio);
 #endif
 
+static ssize_t sheaves_enabled_show(struct kmem_cache *s, char *buf)
+{
+	if (s->cpu_sheaves)
+		return sysfs_emit(buf, "%u\n", 1);
+	else
+		return sysfs_emit(buf, "%u\n", 0);
+}
+SLAB_ATTR_RO(sheaves_enabled);
+
 #ifdef CONFIG_SLUB_STATS
 static int show_stat(struct kmem_cache *s, char *buf, enum stat_item si)
 {
@@ -8656,6 +8665,7 @@ static struct attribute *slab_attrs[] = {
 #ifdef CONFIG_NUMA
 	&remote_node_defrag_ratio_attr.attr,
 #endif
+	&sheaves_enabled_attr.attr,
 #ifdef CONFIG_SLUB_STATS
 	&alloc_cpu_sheaf_attr.attr,
 	&alloc_fastpath_attr.attr,
-- 
2.43.0