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authorPatrick McHardy <kaber@trash.net>2008-07-05 23:21:31 -0700
committerDavid S. Miller <davem@davemloft.net>2008-07-05 23:21:31 -0700
commit6fe1c7a5556807e9d7154a2d2fb938d8a9e47e5f (patch)
tree27758ea169b402aba70ef68bde8e554e7f135031 /net/sched
parentea2aca084ba82aaf7c148d04914ceed8758ce08a (diff)
net-sched: add dynamically sized qdisc class hash helpers
Currently all qdiscs which allow to create classes uses a fixed sized hash table with size 16 to hash the classes. This causes a large bottleneck when using thousands of classes and unbound filters. Add helpers for dynamically sized class hashes to fix this. The following patches will convert the qdiscs to use them. Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/sched')
-rw-r--r--net/sched/sch_api.c104
1 files changed, 104 insertions, 0 deletions
diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index 10f01ad0438..e9ebc7af049 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -316,6 +316,110 @@ void qdisc_watchdog_cancel(struct qdisc_watchdog *wd)
}
EXPORT_SYMBOL(qdisc_watchdog_cancel);
+struct hlist_head *qdisc_class_hash_alloc(unsigned int n)
+{
+ unsigned int size = n * sizeof(struct hlist_head), i;
+ struct hlist_head *h;
+
+ if (size <= PAGE_SIZE)
+ h = kmalloc(size, GFP_KERNEL);
+ else
+ h = (struct hlist_head *)
+ __get_free_pages(GFP_KERNEL, get_order(size));
+
+ if (h != NULL) {
+ for (i = 0; i < n; i++)
+ INIT_HLIST_HEAD(&h[i]);
+ }
+ return h;
+}
+
+static void qdisc_class_hash_free(struct hlist_head *h, unsigned int n)
+{
+ unsigned int size = n * sizeof(struct hlist_head);
+
+ if (size <= PAGE_SIZE)
+ kfree(h);
+ else
+ free_pages((unsigned long)h, get_order(size));
+}
+
+void qdisc_class_hash_grow(struct Qdisc *sch, struct Qdisc_class_hash *clhash)
+{
+ struct Qdisc_class_common *cl;
+ struct hlist_node *n, *next;
+ struct hlist_head *nhash, *ohash;
+ unsigned int nsize, nmask, osize;
+ unsigned int i, h;
+
+ /* Rehash when load factor exceeds 0.75 */
+ if (clhash->hashelems * 4 <= clhash->hashsize * 3)
+ return;
+ nsize = clhash->hashsize * 2;
+ nmask = nsize - 1;
+ nhash = qdisc_class_hash_alloc(nsize);
+ if (nhash == NULL)
+ return;
+
+ ohash = clhash->hash;
+ osize = clhash->hashsize;
+
+ sch_tree_lock(sch);
+ for (i = 0; i < osize; i++) {
+ hlist_for_each_entry_safe(cl, n, next, &ohash[i], hnode) {
+ h = qdisc_class_hash(cl->classid, nmask);
+ hlist_add_head(&cl->hnode, &nhash[h]);
+ }
+ }
+ clhash->hash = nhash;
+ clhash->hashsize = nsize;
+ clhash->hashmask = nmask;
+ sch_tree_unlock(sch);
+
+ qdisc_class_hash_free(ohash, osize);
+}
+EXPORT_SYMBOL(qdisc_class_hash_grow);
+
+int qdisc_class_hash_init(struct Qdisc_class_hash *clhash)
+{
+ unsigned int size = 4;
+
+ clhash->hash = qdisc_class_hash_alloc(size);
+ if (clhash->hash == NULL)
+ return -ENOMEM;
+ clhash->hashsize = size;
+ clhash->hashmask = size - 1;
+ clhash->hashelems = 0;
+ return 0;
+}
+EXPORT_SYMBOL(qdisc_class_hash_init);
+
+void qdisc_class_hash_destroy(struct Qdisc_class_hash *clhash)
+{
+ qdisc_class_hash_free(clhash->hash, clhash->hashsize);
+}
+EXPORT_SYMBOL(qdisc_class_hash_destroy);
+
+void qdisc_class_hash_insert(struct Qdisc_class_hash *clhash,
+ struct Qdisc_class_common *cl)
+{
+ unsigned int h;
+
+ INIT_HLIST_NODE(&cl->hnode);
+ h = qdisc_class_hash(cl->classid, clhash->hashmask);
+ hlist_add_head(&cl->hnode, &clhash->hash[h]);
+ clhash->hashelems++;
+}
+EXPORT_SYMBOL(qdisc_class_hash_insert);
+
+void qdisc_class_hash_remove(struct Qdisc_class_hash *clhash,
+ struct Qdisc_class_common *cl)
+{
+ hlist_del(&cl->hnode);
+ clhash->hashelems--;
+}
+EXPORT_SYMBOL(qdisc_class_hash_remove);
+
/* Allocate an unique handle from space managed by kernel */
static u32 qdisc_alloc_handle(struct net_device *dev)