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From: Waiman Long <longman@redhat.com>
To: Alexander Viro <viro@zeniv.linux.org.uk>,
	Jonathan Corbet <corbet@lwn.net>,
	Andrew Morton <akpm@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-mm@kvack.org, linux-doc@vger.kernel.org,
	"Luis R. Rodriguez" <mcgrof@kernel.org>,
	Kees Cook <keescook@chromium.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Jan Kara <jack@suse.cz>,
	"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
	Ingo Molnar <mingo@kernel.org>,
	Miklos Szeredi <mszeredi@redhat.com>,
	Matthew Wilcox <willy@infradead.org>,
	Larry Woodman <lwoodman@redhat.com>,
	James Bottomley <James.Bottomley@HansenPartnership.com>,
	"Wangkai (Kevin C)" <wangkai86@huawei.com>,
	Michal Hocko <mhocko@kernel.org>,
	Waiman Long <longman@redhat.com>
Subject: [PATCH v4 2/3] fs: Don't need to put list_lru into its own cacheline
Date: Wed, 12 Sep 2018 13:35:41 -0400	[thread overview]
Message-ID: <1536773742-32687-3-git-send-email-longman@redhat.com> (raw)
In-Reply-To: <1536773742-32687-1-git-send-email-longman@redhat.com>

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 <longman@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
---
 include/linux/fs.h | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/include/linux/fs.h b/include/linux/fs.h
index 3332270..fd4cd8a 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1443,11 +1443,12 @@ 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;
 
-- 
1.8.3.1

  parent reply	other threads:[~2018-09-12 17:35 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-09-12 17:35 [PATCH v4 0/3] fs/dcache: Track # of negative dentries Waiman Long
2018-09-12 17:35 ` [PATCH v4 1/3] fs/dcache: Fix incorrect nr_dentry_unused accounting in shrink_dcache_sb() Waiman Long
2018-09-12 17:35 ` Waiman Long [this message]
2018-09-12 17:35 ` [PATCH v4 3/3] fs/dcache: Track & report number of negative dentries Waiman Long
2018-10-05 14:55 ` [PATCH v4 0/3] fs/dcache: Track # " Waiman Long

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