net: cacheline adjust struct inet_frags for better frag performance
The globally shared rwlock, of struct inet_frags, shares
cacheline with the 'rnd' number, which is used by the hash
calculations. Fix this, as this obviously is a bad idea, as
unnecessary cache-misses will occur when accessing the 'rnd'
number.
Also small note that, moving function ptr (*match) up in struct,
is to avoid it lands on the next cacheline (on 64-bit).
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/inet_frag.h b/include/net/inet_frag.h
index 91e7797..54c1de7 100644
--- a/include/net/inet_frag.h
+++ b/include/net/inet_frag.h
@@ -40,18 +40,21 @@
struct inet_frags {
struct hlist_head hash[INETFRAGS_HASHSZ];
- rwlock_t lock;
- u32 rnd;
- int qsize;
+ /* This rwlock is a global lock (seperate per IPv4, IPv6 and
+ * netfilter). Important to keep this on a seperate cacheline.
+ */
+ rwlock_t lock ____cacheline_aligned_in_smp;
int secret_interval;
struct timer_list secret_timer;
+ u32 rnd;
+ int qsize;
unsigned int (*hashfn)(struct inet_frag_queue *);
+ bool (*match)(struct inet_frag_queue *q, void *arg);
void (*constructor)(struct inet_frag_queue *q,
void *arg);
void (*destructor)(struct inet_frag_queue *);
void (*skb_free)(struct sk_buff *);
- bool (*match)(struct inet_frag_queue *q, void *arg);
void (*frag_expire)(unsigned long data);
};