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authorEric Dumazet <edumazet@google.com>2018-03-31 22:58:56 +0300
committerDavid S. Miller <davem@davemloft.net>2018-04-01 06:25:39 +0300
commite5d672a0780d9e7118caad4c171ec88b8299398d (patch)
tree2d885d704df9eee43788e94bcac1142dd9b519fc
parent05c0b86b9696802fd0ce5676a92a63f1b455bdf3 (diff)
downloadlinux-e5d672a0780d9e7118caad4c171ec88b8299398d.tar.xz
rhashtable: reorganize struct rhashtable layout
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>
-rw-r--r--include/linux/rhashtable.h8
1 files changed, 4 insertions, 4 deletions
diff --git a/include/linux/rhashtable.h b/include/linux/rhashtable.h
index 668a21f04b09..1f8ad121eb43 100644
--- 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;
};
/**