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flow, tcp: Add handling for per-flow timers

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tcp_timer() scans the flow table so that it can run tcp_splice_timer() on
each spliced connection.  More generally, other flow types might want to
run similar timers in future.

We could add a flow_timer() analagous to tcp_timer(), udp_timer() etc.
However, this would need to scan the flow table, which we would have just
done in flow_defer_handler().  We'd prefer to just scan the flow table
once, dispatching both per-flow deferred events and per-flow timed events
if necessary.

So, extend flow_defer_handler() to do this.  For now we use the same timer
interval for all flow types (1s).  We can make that more flexible in future
if we need to.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
This commit is contained in:
David Gibson 2024-01-16 11:50:36 +11:00 committed by Stefano Brivio
parent b43e4483ed
commit 36dfa8b8fb
4 changed files with 21 additions and 12 deletions
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16
flow.c
View file

@ -28,6 +28,9 @@ static_assert(ARRAY_SIZE(flow_type_str) == FLOW_NUM_TYPES,
/* Global Flow Table */
union flow flowtab[FLOW_MAX];
/* Last time the flow timers ran */
static struct timespec flow_timer_run;
/**
* flow_table_compact() - Perform compaction on flow table
* @c: Execution context
@ -86,13 +89,20 @@ void flow_log_(const struct flow_common *f, int pri, const char *fmt, ...)
}
/**
* flow_defer_handler() - Handler for per-flow deferred tasks
* flow_defer_handler() - Handler for per-flow deferred and timed tasks
* @c: Execution context
* @now: Current timestamp
*/
void flow_defer_handler(struct ctx *c)
void flow_defer_handler(struct ctx *c, const struct timespec *now)
{
bool timer = false;
union flow *flow;
if (timespec_diff_ms(now, &flow_timer_run) >= FLOW_TIMER_INTERVAL) {
timer = true;
flow_timer_run = *now;
}
for (flow = flowtab + c->flow_count - 1; flow >= flowtab; flow--) {
switch (flow->f.type) {
case FLOW_TCP:
@ -100,6 +110,8 @@ void flow_defer_handler(struct ctx *c)
break;
case FLOW_TCP_SPLICE:
tcp_splice_flow_defer(c, flow);
if (timer)
tcp_splice_timer(c, flow);
break;
default:
/* Assume other flow types don't need any handling */

4
flow.h
View file

@ -7,6 +7,8 @@
#ifndef FLOW_H
#define FLOW_H
#define FLOW_TIMER_INTERVAL 1000 /* ms */
/**
* enum flow_type - Different types of packet flows we track
*/
@ -67,7 +69,7 @@ static inline bool flow_sidx_eq(flow_sidx_t a, flow_sidx_t b)
union flow;
void flow_table_compact(struct ctx *c, union flow *hole);
void flow_defer_handler(struct ctx *c);
void flow_defer_handler(struct ctx *c, const struct timespec *now);
void flow_log_(const struct flow_common *f, int pri, const char *fmt, ...)
__attribute__((format(printf, 3, 4)));

7
passt.c
View file

@ -53,8 +53,9 @@
#define EPOLL_EVENTS 8
#define __TIMER_INTERVAL MIN(TCP_TIMER_INTERVAL, UDP_TIMER_INTERVAL)
#define TIMER_INTERVAL MIN(__TIMER_INTERVAL, ICMP_TIMER_INTERVAL)
#define TIMER_INTERVAL__ MIN(TCP_TIMER_INTERVAL, UDP_TIMER_INTERVAL)
#define TIMER_INTERVAL_ MIN(TIMER_INTERVAL__, ICMP_TIMER_INTERVAL)
#define TIMER_INTERVAL MIN(TIMER_INTERVAL_, FLOW_TIMER_INTERVAL)
char pkt_buf[PKT_BUF_BYTES] __attribute__ ((aligned(PAGE_SIZE)));
@ -103,7 +104,7 @@ static void post_handler(struct ctx *c, const struct timespec *now)
/* NOLINTNEXTLINE(bugprone-branch-clone): intervals can be the same */
CALL_PROTO_HANDLER(c, now, icmp, ICMP);
flow_defer_handler(c);
flow_defer_handler(c, now);
#undef CALL_PROTO_HANDLER
}

6
tcp.c
View file

@ -3171,8 +3171,6 @@ static int tcp_port_rebind_outbound(void *arg)
*/
void tcp_timer(struct ctx *c, const struct timespec *now)
{
union flow *flow;
(void)now;
if (c->mode == MODE_PASTA) {
@ -3187,10 +3185,6 @@ void tcp_timer(struct ctx *c, const struct timespec *now)
}
}
for (flow = flowtab + c->flow_count - 1; flow >= flowtab; flow--)
if (flow->f.type == FLOW_TCP_SPLICE)
tcp_splice_timer(c, flow);
tcp_sock_refill_init(c);
if (c->mode == MODE_PASTA)
tcp_splice_refill(c);