From 78680c6fce480d7b9be38a1b5a1fca4df7092591 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marek=20Vavru=C5=A1a?= <marek.vavrusa@nic.cz>
Date: Thu, 5 Feb 2015 15:13:49 +0100
Subject: [PATCH] tcp: throttling affect accept() only, lets the processing
continue
---
src/knot/server/tcp-handler.c | 32 +++++++++++++++++++-------------
1 file changed, 19 insertions(+), 13 deletions(-)
diff --git a/src/knot/server/tcp-handler.c b/src/knot/server/tcp-handler.c
index f8a83a2d4..70099c773 100644
--- a/src/knot/server/tcp-handler.c
+++ b/src/knot/server/tcp-handler.c
@@ -48,6 +48,7 @@ typedef struct tcp_context {
struct iovec iov[2]; /*!< TX/RX buffers. */
unsigned client_threshold; /*!< Index of first TCP client. */
timev_t last_poll_time; /*!< Time of the last socket poll. */
+ timev_t throttle_end; /*!< End of accept() throttling. */
fdset_t set; /*!< Set of server/client sockets. */
unsigned thread_id; /*!< Thread identifier. */
} tcp_context_t;
@@ -108,7 +109,9 @@ static int tcp_handle(tcp_context_t *tcp, int fd,
}
/* Timeout. */
+ rcu_read_lock();
struct timeval tmout = { conf()->max_conn_reply, 0 };
+ rcu_read_unlock();
/* Receive data. */
int ret = tcp_recv_msg(fd, rx->iov_base, rx->iov_len, &tmout);
@@ -164,17 +167,9 @@ int tcp_accept(int fd)
if (incoming < 0) {
int en = errno;
if (en != EINTR && en != EAGAIN) {
- log_error("cannot accept connection (%d)", errno);
- if (en == EMFILE || en == ENFILE ||
- en == ENOBUFS || en == ENOMEM) {
- int throttle = tcp_throttle();
- log_error("throttling TCP connection pool for "
- "%d seconds, too many allocated "
- "resources", throttle);
- sleep(throttle);
- }
-
+ return KNOT_EBUSY;
}
+ return KNOT_ERROR;
} else {
dbg_net("tcp: accepted connection fd=%d\n", incoming);
/* Set recv() timeout. */
@@ -230,7 +225,7 @@ int tcp_recv_data(int fd, uint8_t *buf, int len, struct timeval *timeout)
if (errno == EAGAIN || errno == EINTR) {
/* Continue only if timeout didn't expire. */
ret = tcp_wait_for_data(fd, timeout);
- if (ret) {
+ if (ret > 0) {
continue;
} else {
return KNOT_ETIMEOUT;
@@ -299,7 +294,7 @@ static int tcp_event_accept(tcp_context_t *tcp, unsigned i)
/* Accept client. */
int fd = tcp->set.pfd[i].fd;
int client = tcp_accept(fd);
- if (client >= 0) {
+ if (client > 0) {
/* Assign to fdset. */
int next_id = fdset_add(&tcp->set, client, POLLIN, NULL);
if (next_id < 0) {
@@ -311,9 +306,11 @@ static int tcp_event_accept(tcp_context_t *tcp, unsigned i)
rcu_read_lock();
fdset_set_watchdog(&tcp->set, next_id, conf()->max_conn_hs);
rcu_read_unlock();
+
+ return KNOT_EOK;
}
- return KNOT_EOK;
+ return client;
}
static int tcp_event_serve(tcp_context_t *tcp, unsigned i)
@@ -342,6 +339,15 @@ static int tcp_wait_for_events(tcp_context_t *tcp)
/* Mark the time of last poll call. */
time_now(&tcp->last_poll_time);
+ bool is_throttled = (tcp->last_poll_time.tv_sec < tcp->throttle_end.tv_sec);
+ rcu_read_lock();
+ if (!is_throttled) {
+ /* Configuration limit, infer maximal pool size. */
+ unsigned max_per_set = MAX(conf()->max_tcp_clients / conf_tcp_threads(conf()), 1);
+ /* Subtract master sockets check limits. */
+ is_throttled = (set->n - tcp->client_threshold) >= max_per_set;
+ }
+ rcu_read_unlock();
/* Process events. */
unsigned i = 0;
--
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