fs: Don't need to put list_lru into its own cacheline

Waiman-Long · torvalds · commit 7d10f70fc198 · 2019-01-30T11:02:11.000-08:00
The list_lru structure is essentially just a pointer to a table of
per-node LRU lists.  Even if CONFIG_MEMCG_KMEM is defined, the list
field is just used for LRU list registration and shrinker_id is set at
initialization.  Those fields won't need to be touched that often.

So there is no point to make the list_lru structures to sit in their own
cachelines.

Signed-off-by: Waiman Long &lt;longman@redhat.com&gt;
Reviewed-by: Dave Chinner &lt;dchinner@redhat.com&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
diff --git a/include/linux/fs.h b/include/linux/fs.h
@@ -1479,11 +1479,12 @@ struct super_block {
 	struct user_namespace *s_user_ns;
 
 	/*
-	 * Keep the lru lists last in the structure so they always sit on their
-	 * own individual cachelines.
+	 * The list_lru structure is essentially just a pointer to a table
+	 * of per-node lru lists, each of which has its own spinlock.
+	 * There is no need to put them into separate cachelines.
 	 */
-	struct list_lru		s_dentry_lru ____cacheline_aligned_in_smp;
-	struct list_lru		s_inode_lru ____cacheline_aligned_in_smp;
+	struct list_lru		s_dentry_lru;
+	struct list_lru		s_inode_lru;
 	struct rcu_head		rcu;
 	struct work_struct	destroy_work;
 
