[PATCH v3 16/30] rhashtable: reorganize struct rhashtable layout
From: Stephen Hemminger <stephen@networkplumber.org>
Date: 2018-09-13 20:09:24
Also in:
stable
Subsystem:
rhashtable, the rest · Maintainers:
Thomas Graf, Herbert Xu, Linus Torvalds
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) --- include/linux/rhashtable.h | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/include/linux/rhashtable.h b/include/linux/rhashtable.h
index 7fd514f36e74..a4be6388a980 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; }; /**
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2.18.0