summaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
-rw-r--r--net/sunrpc/cache.c67
1 files changed, 43 insertions, 24 deletions
diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c
index 49115b1..ba61d0f 100644
--- a/net/sunrpc/cache.c
+++ b/net/sunrpc/cache.c
@@ -513,22 +513,25 @@ static int cache_defer_cnt;
static void __unhash_deferred_req(struct cache_deferred_req *dreq)
{
- list_del_init(&dreq->recent);
hlist_del_init(&dreq->hash);
- cache_defer_cnt--;
+ if (!list_empty(&dreq->recent)) {
+ list_del_init(&dreq->recent);
+ cache_defer_cnt--;
+ }
}
static void __hash_deferred_req(struct cache_deferred_req *dreq, struct cache_head *item)
{
int hash = DFR_HASH(item);
- list_add(&dreq->recent, &cache_defer_list);
+ INIT_LIST_HEAD(&dreq->recent);
hlist_add_head(&dreq->hash, &cache_defer_hash[hash]);
}
-static void setup_deferral(struct cache_deferred_req *dreq, struct cache_head *item)
+static void setup_deferral(struct cache_deferred_req *dreq,
+ struct cache_head *item,
+ int count_me)
{
- struct cache_deferred_req *discard;
dreq->item = item;
@@ -536,18 +539,13 @@ static void setup_deferral(struct cache_deferred_req *dreq, struct cache_head *i
__hash_deferred_req(dreq, item);
- /* it is in, now maybe clean up */
- discard = NULL;
- if (++cache_defer_cnt > DFR_MAX) {
- discard = list_entry(cache_defer_list.prev,
- struct cache_deferred_req, recent);
- __unhash_deferred_req(discard);
+ if (count_me) {
+ cache_defer_cnt++;
+ list_add(&dreq->recent, &cache_defer_list);
}
+
spin_unlock(&cache_defer_lock);
- if (discard)
- /* there was one too many */
- discard->revisit(discard, 1);
}
struct thread_deferred_req {
@@ -570,7 +568,7 @@ static void cache_wait_req(struct cache_req *req, struct cache_head *item)
sleeper.completion = COMPLETION_INITIALIZER_ONSTACK(sleeper.completion);
dreq->revisit = cache_restart_thread;
- setup_deferral(dreq, item);
+ setup_deferral(dreq, item, 0);
if (!test_bit(CACHE_PENDING, &item->flags) ||
wait_for_completion_interruptible_timeout(
@@ -594,17 +592,36 @@ static void cache_wait_req(struct cache_req *req, struct cache_head *item)
}
}
-static void cache_defer_req(struct cache_req *req, struct cache_head *item)
+static void cache_limit_defers(void)
{
- struct cache_deferred_req *dreq;
+ /* Make sure we haven't exceed the limit of allowed deferred
+ * requests.
+ */
+ struct cache_deferred_req *discard = NULL;
- if (cache_defer_cnt >= DFR_MAX)
- /* too much in the cache, randomly drop this one,
- * or continue and drop the oldest
- */
- if (net_random()&1)
- return;
+ if (cache_defer_cnt <= DFR_MAX)
+ return;
+
+ spin_lock(&cache_defer_lock);
+ /* Consider removing either the first or the last */
+ if (cache_defer_cnt > DFR_MAX) {
+ if (net_random() & 1)
+ discard = list_entry(cache_defer_list.next,
+ struct cache_deferred_req, recent);
+ else
+ discard = list_entry(cache_defer_list.prev,
+ struct cache_deferred_req, recent);
+ __unhash_deferred_req(discard);
+ }
+ spin_unlock(&cache_defer_lock);
+ if (discard)
+ discard->revisit(discard, 1);
+}
+
+static void cache_defer_req(struct cache_req *req, struct cache_head *item)
+{
+ struct cache_deferred_req *dreq;
if (req->thread_wait) {
cache_wait_req(req, item);
@@ -614,12 +631,14 @@ static void cache_defer_req(struct cache_req *req, struct cache_head *item)
dreq = req->defer(req);
if (dreq == NULL)
return;
- setup_deferral(dreq, item);
+ setup_deferral(dreq, item, 1);
if (!test_bit(CACHE_PENDING, &item->flags))
/* Bit could have been cleared before we managed to
* set up the deferral, so need to revisit just in case
*/
cache_revisit_request(item);
+
+ cache_limit_defers();
}
static void cache_revisit_request(struct cache_head *item)
OpenPOWER on IntegriCloud