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Use different allocators for UDP and TCP

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Each worker has a receive buffer with space for 20 DNS messages of up
to 2^16 bytes each, and the allocator function passed to uv_read_start()
or uv_udp_recv_start() will reserve a portion of it for use by sockets.
UDP can use recvmmsg() and so it needs that entire space, but TCP reads
one message at a time.

This commit introduces separate allocator functions for TCP and UDP
setting different buffer size limits, so that libuv will provide the
correct buffer sizes to each of them.
This commit is contained in:
Evan Hunt
2020-07-02 16:27:38 +02:00
committed by Michał Kępień
parent f0fa6f0245
commit 38264b6a4d
4 changed files with 53 additions and 30 deletions
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28
lib/isc/netmgr/udp.c
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@@ -132,6 +132,32 @@ isc_nm_listenudp(isc_nm_t *mgr, isc_nmiface_t *iface, isc_nm_recv_cb_t cb,
return (ISC_R_SUCCESS);
}
/*%<
* Allocator for UDP recv operations. Limited to size 20 * (2^16 + 2),
* which allows enough space for recvmmsg() to get multiple messages at
* a time.
*
* Note this doesn't actually allocate anything, it just assigns the
* worker's receive buffer to a socket, and marks it as "in use".
*/
static void
udp_alloc_cb(uv_handle_t *handle, size_t size, uv_buf_t *buf) {
isc_nmsocket_t *sock = uv_handle_get_data(handle);
isc__networker_t *worker = NULL;
REQUIRE(VALID_NMSOCK(sock));
REQUIRE(sock->type == isc_nm_udpsocket);
REQUIRE(isc__nm_in_netthread());
REQUIRE(size <= ISC_NETMGR_RECVBUF_SIZE);
worker = &sock->mgr->workers[sock->tid];
INSIST(!worker->recvbuf_inuse);
buf->base = worker->recvbuf;
buf->len = ISC_NETMGR_RECVBUF_SIZE;
worker->recvbuf_inuse = true;
}
/*
* handle 'udplisten' async call - start listening on a socket.
*/
@@ -193,7 +219,7 @@ isc__nm_async_udplisten(isc__networker_t *worker, isc__netievent_t *ev0) {
uv_send_buffer_size(&sock->uv_handle.handle,
&(int){ ISC_SEND_BUFFER_SIZE });
#endif
uv_udp_recv_start(&sock->uv_handle.udp, isc__nm_alloc_cb, udp_recv_cb);
uv_udp_recv_start(&sock->uv_handle.udp, udp_alloc_cb, udp_recv_cb);
}
static void