net: frag, move LRU list maintenance outside of rwlock
Updating the fragmentation queues LRU (Least-Recently-Used) list,
required taking the hash writer lock. However, the LRU list isn't
tied to the hash at all, so we can use a separate lock for it.
Original-idea-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/inet_fragment.c b/net/ipv4/inet_fragment.c
index b825205..2e453bd 100644
--- a/net/ipv4/inet_fragment.c
+++ b/net/ipv4/inet_fragment.c
@@ -75,6 +75,7 @@
nf->nqueues = 0;
init_frag_mem_limit(nf);
INIT_LIST_HEAD(&nf->lru_list);
+ spin_lock_init(&nf->lru_lock);
}
EXPORT_SYMBOL(inet_frags_init_net);
@@ -100,9 +101,9 @@
{
write_lock(&f->lock);
hlist_del(&fq->list);
- list_del(&fq->lru_list);
fq->net->nqueues--;
write_unlock(&f->lock);
+ inet_frag_lru_del(fq);
}
void inet_frag_kill(struct inet_frag_queue *fq, struct inet_frags *f)
@@ -170,16 +171,17 @@
work = frag_mem_limit(nf) - nf->low_thresh;
while (work > 0) {
- read_lock(&f->lock);
+ spin_lock(&nf->lru_lock);
+
if (list_empty(&nf->lru_list)) {
- read_unlock(&f->lock);
+ spin_unlock(&nf->lru_lock);
break;
}
q = list_first_entry(&nf->lru_list,
struct inet_frag_queue, lru_list);
atomic_inc(&q->refcnt);
- read_unlock(&f->lock);
+ spin_unlock(&nf->lru_lock);
spin_lock(&q->lock);
if (!(q->last_in & INET_FRAG_COMPLETE))
@@ -233,9 +235,9 @@
atomic_inc(&qp->refcnt);
hlist_add_head(&qp->list, &f->hash[hash]);
- list_add_tail(&qp->lru_list, &nf->lru_list);
nf->nqueues++;
write_unlock(&f->lock);
+ inet_frag_lru_add(nf, qp);
return qp;
}