summaryrefslogtreecommitdiff
path: root/include/linux/slab_def.h
diff options
context:
space:
mode:
Diffstat (limited to 'include/linux/slab_def.h')
-rw-r--r--include/linux/slab_def.h13
1 files changed, 13 insertions, 0 deletions
diff --git a/include/linux/slab_def.h b/include/linux/slab_def.h
index 3485c58cfd1c..9a5eafb7145b 100644
--- a/include/linux/slab_def.h
+++ b/include/linux/slab_def.h
@@ -104,4 +104,17 @@ static inline void *nearest_obj(struct kmem_cache *cache, struct page *page,
return object;
}
+/*
+ * We want to avoid an expensive divide : (offset / cache->size)
+ * Using the fact that size is a constant for a particular cache,
+ * we can replace (offset / cache->size) by
+ * reciprocal_divide(offset, cache->reciprocal_buffer_size)
+ */
+static inline unsigned int obj_to_index(const struct kmem_cache *cache,
+ const struct page *page, void *obj)
+{
+ u32 offset = (obj - page->s_mem);
+ return reciprocal_divide(offset, cache->reciprocal_buffer_size);
+}
+
#endif /* _LINUX_SLAB_DEF_H */