| From foo@baz Mon Sep 17 13:33:56 CEST 2018 |
| From: Stephen Hemminger <stephen@networkplumber.org> |
| Date: Thu, 13 Sep 2018 07:58:48 -0700 |
| Subject: rhashtable: reorganize struct rhashtable layout |
| To: davem@davemloft.net, gregkh@linuxfoundation.org |
| Cc: netdev@vger.kernel.org, stable@vger.kernel.org, edumazet@google.com |
| Message-ID: <20180913145902.17531-17-sthemmin@microsoft.com> |
| |
| From: Eric Dumazet <edumazet@google.com> |
| |
| 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 <edumazet@google.com> |
| Signed-off-by: David S. Miller <davem@davemloft.net> |
| (cherry picked from commit e5d672a0780d9e7118caad4c171ec88b8299398d) |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| 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; |
| }; |
| |
| /** |
