From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:49310 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731087AbeIREew (ORCPT ); Tue, 18 Sep 2018 00:34:52 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Eric Dumazet , "David S. Miller" Subject: [PATCH 4.14 107/126] rhashtable: reorganize struct rhashtable layout Date: Tue, 18 Sep 2018 00:42:35 +0200 Message-Id: <20180917211710.991475116@linuxfoundation.org> In-Reply-To: <20180917211703.481236999@linuxfoundation.org> References: <20180917211703.481236999@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet While under frags DDOS I noticed unfortunate false sharing between @nelems and @params.automatic_shrinking Move @nelems at the end of struct rhashtable so that first cache line is shared between all cpus, because almost never dirtied. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller (cherry picked from commit e5d672a0780d9e7118caad4c171ec88b8299398d) Signed-off-by: Greg Kroah-Hartman --- include/linux/rhashtable.h | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) --- a/include/linux/rhashtable.h +++ b/include/linux/rhashtable.h @@ -152,25 +152,25 @@ struct rhashtable_params { /** * struct rhashtable - Hash table handle * @tbl: Bucket table - * @nelems: Number of elements in table * @key_len: Key length for hashfn - * @p: Configuration parameters * @max_elems: Maximum number of elements in table + * @p: Configuration parameters * @rhlist: True if this is an rhltable * @run_work: Deferred worker to expand/shrink asynchronously * @mutex: Mutex to protect current/future table swapping * @lock: Spin lock to protect walker list + * @nelems: Number of elements in table */ struct rhashtable { struct bucket_table __rcu *tbl; - atomic_t nelems; unsigned int key_len; - struct rhashtable_params p; unsigned int max_elems; + struct rhashtable_params p; bool rhlist; struct work_struct run_work; struct mutex mutex; spinlock_t lock; + atomic_t nelems; }; /**