MEDIUM: quic: use a global CID trees list
Previously, quic_connection_id were stored in a per-thread tree list.
Datagram were first dispatched to the correct thread using the encoded
TID before a tree lookup was done.
Remove these trees and replace it with a global trees list of 256
entries. A CID is using the list index corresponding to its first byte.
On datagram dispatch, CID is lookup on its tree and TID is retrieved
using new member quic_connection_id.tid. As such, a read-write lock
protects each list instances. With 256 entries, it is expected that
contention should be reduced.
A new structure quic_cid_tree served as a tree container associated with
its read-write lock. An API is implemented to ensure lock safety for
insert/lookup/delete operation.
This patch is a step forward to be able to break the affinity between a
CID and a TID encoded thread. This is required to be able to migrate a
quic_conn after accept to select thread based on their load.
This should be backported up to 2.7 after a period of observation.
diff --git a/src/proto_quic.c b/src/proto_quic.c
index b1708eb..0961fc2 100644
--- a/src/proto_quic.c
+++ b/src/proto_quic.c
@@ -51,6 +51,11 @@
/* per-thread quic datagram handlers */
struct quic_dghdlr *quic_dghdlrs;
+struct eb_root *quic_cid_tree;
+
+/* global CID trees */
+#define QUIC_CID_TREES_CNT 256
+struct quic_cid_tree *quic_cid_trees;
/* Size of the internal buffer of QUIC RX buffer at the fd level */
#define QUIC_RX_BUFSZ (1UL << 18)
@@ -734,11 +739,20 @@
dghdlr->task->context = dghdlr;
dghdlr->task->process = quic_lstnr_dghdlr;
- dghdlr->cids = EB_ROOT_UNIQUE;
-
MT_LIST_INIT(&dghdlr->dgrams);
}
+ quic_cid_trees = calloc(QUIC_CID_TREES_CNT, sizeof(struct quic_cid_tree));
+ if (!quic_cid_trees) {
+ ha_alert("Failed to allocate global CIDs trees.\n");
+ return 0;
+ }
+
+ for (i = 0; i < QUIC_CID_TREES_CNT; ++i) {
+ HA_RWLOCK_INIT(&quic_cid_trees[i].lock);
+ quic_cid_trees[i].root = EB_ROOT_UNIQUE;
+ }
+
return 1;
}
REGISTER_POST_CHECK(quic_alloc_dghdlrs);
@@ -753,6 +767,8 @@
free(quic_dghdlrs);
}
+ ha_free(&quic_cid_trees);
+
return 1;
}
REGISTER_POST_DEINIT(quic_deallocate_dghdlrs);