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Subject[PATCH net-next 6/7] rxrpc: Keep the call timeouts as ktimes rather than jiffies
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Date
Keep that call timeouts as ktimes rather than jiffies so that they can be
expressed as functions of RTT.

Signed-off-by: David Howells <dhowells@redhat.com>
---

include/trace/events/rxrpc.h | 25 +++++++-------
net/rxrpc/ar-internal.h | 8 ++---
net/rxrpc/call_event.c | 73 ++++++++++++++++++++++--------------------
net/rxrpc/call_object.c | 16 +++------
net/rxrpc/input.c | 3 +-
net/rxrpc/misc.c | 15 ++++++---
net/rxrpc/sendmsg.c | 8 ++---
net/rxrpc/sysctl.c | 8 ++---
8 files changed, 82 insertions(+), 74 deletions(-)

diff --git a/include/trace/events/rxrpc.h b/include/trace/events/rxrpc.h
index 67f03946ea4a..0383e5e9a0f3 100644
--- a/include/trace/events/rxrpc.h
+++ b/include/trace/events/rxrpc.h
@@ -453,17 +453,18 @@ TRACE_EVENT(rxrpc_rtt_rx,

TRACE_EVENT(rxrpc_timer,
TP_PROTO(struct rxrpc_call *call, enum rxrpc_timer_trace why,
- unsigned long now),
+ ktime_t now, unsigned long now_j),

- TP_ARGS(call, why, now),
+ TP_ARGS(call, why, now, now_j),

TP_STRUCT__entry(
__field(struct rxrpc_call *, call )
__field(enum rxrpc_timer_trace, why )
- __field(unsigned long, now )
- __field(unsigned long, expire_at )
- __field(unsigned long, ack_at )
- __field(unsigned long, resend_at )
+ __field_struct(ktime_t, now )
+ __field_struct(ktime_t, expire_at )
+ __field_struct(ktime_t, ack_at )
+ __field_struct(ktime_t, resend_at )
+ __field(unsigned long, now_j )
__field(unsigned long, timer )
),

@@ -474,17 +475,17 @@ TRACE_EVENT(rxrpc_timer,
__entry->expire_at = call->expire_at;
__entry->ack_at = call->ack_at;
__entry->resend_at = call->resend_at;
+ __entry->now_j = now_j;
__entry->timer = call->timer.expires;
),

- TP_printk("c=%p %s now=%lx x=%ld a=%ld r=%ld t=%ld",
+ TP_printk("c=%p %s x=%lld a=%lld r=%lld t=%ld",
__entry->call,
rxrpc_timer_traces[__entry->why],
- __entry->now,
- __entry->expire_at - __entry->now,
- __entry->ack_at - __entry->now,
- __entry->resend_at - __entry->now,
- __entry->timer - __entry->now)
+ ktime_to_ns(ktime_sub(__entry->expire_at, __entry->now)),
+ ktime_to_ns(ktime_sub(__entry->ack_at, __entry->now)),
+ ktime_to_ns(ktime_sub(__entry->resend_at, __entry->now)),
+ __entry->timer - __entry->now_j)
);

TRACE_EVENT(rxrpc_rx_lose,
diff --git a/net/rxrpc/ar-internal.h b/net/rxrpc/ar-internal.h
index 141c1458e719..d38dffd78085 100644
--- a/net/rxrpc/ar-internal.h
+++ b/net/rxrpc/ar-internal.h
@@ -464,9 +464,9 @@ struct rxrpc_call {
struct rxrpc_connection *conn; /* connection carrying call */
struct rxrpc_peer *peer; /* Peer record for remote address */
struct rxrpc_sock __rcu *socket; /* socket responsible */
- unsigned long ack_at; /* When deferred ACK needs to happen */
- unsigned long resend_at; /* When next resend needs to happen */
- unsigned long expire_at; /* When the call times out */
+ ktime_t ack_at; /* When deferred ACK needs to happen */
+ ktime_t resend_at; /* When next resend needs to happen */
+ ktime_t expire_at; /* When the call times out */
struct timer_list timer; /* Combined event timer */
struct work_struct processor; /* Event processor */
rxrpc_notify_rx_t notify_rx; /* kernel service Rx notification function */
@@ -805,7 +805,7 @@ int rxrpc_reject_call(struct rxrpc_sock *);
/*
* call_event.c
*/
-void rxrpc_set_timer(struct rxrpc_call *, enum rxrpc_timer_trace);
+void rxrpc_set_timer(struct rxrpc_call *, enum rxrpc_timer_trace, ktime_t);
void rxrpc_propose_ACK(struct rxrpc_call *, u8, u16, u32, bool, bool,
enum rxrpc_propose_ack_trace);
void rxrpc_process_call(struct work_struct *);
diff --git a/net/rxrpc/call_event.c b/net/rxrpc/call_event.c
index 1f6c7633b964..9ff3bb3ffb41 100644
--- a/net/rxrpc/call_event.c
+++ b/net/rxrpc/call_event.c
@@ -24,28 +24,40 @@
/*
* Set the timer
*/
-void rxrpc_set_timer(struct rxrpc_call *call, enum rxrpc_timer_trace why)
+void rxrpc_set_timer(struct rxrpc_call *call, enum rxrpc_timer_trace why,
+ ktime_t now)
{
- unsigned long t, now = jiffies;
+ unsigned long t_j, now_j = jiffies;
+ ktime_t t;

read_lock_bh(&call->state_lock);

if (call->state < RXRPC_CALL_COMPLETE) {
t = call->expire_at;
- if (time_before_eq(t, now))
+ if (!ktime_after(t, now))
goto out;

- if (time_after(call->resend_at, now) &&
- time_before(call->resend_at, t))
+ if (ktime_after(call->resend_at, now) &&
+ ktime_before(call->resend_at, t))
t = call->resend_at;

- if (time_after(call->ack_at, now) &&
- time_before(call->ack_at, t))
+ if (ktime_after(call->ack_at, now) &&
+ ktime_before(call->ack_at, t))
t = call->ack_at;

- if (call->timer.expires != t || !timer_pending(&call->timer)) {
- mod_timer(&call->timer, t);
- trace_rxrpc_timer(call, why, now);
+ t_j = nsecs_to_jiffies(ktime_to_ns(ktime_sub(t, now)));
+ t_j += jiffies;
+
+ /* We have to make sure that the calculated jiffies value falls
+ * at or after the nsec value, or we may loop ceaselessly
+ * because the timer times out, but we haven't reached the nsec
+ * timeout yet.
+ */
+ t_j++;
+
+ if (call->timer.expires != t_j || !timer_pending(&call->timer)) {
+ mod_timer(&call->timer, t_j);
+ trace_rxrpc_timer(call, why, now, now_j);
}
}

@@ -62,7 +74,8 @@ static void __rxrpc_propose_ACK(struct rxrpc_call *call, u8 ack_reason,
enum rxrpc_propose_ack_trace why)
{
enum rxrpc_propose_ack_outcome outcome = rxrpc_propose_ack_use;
- unsigned long now, ack_at, expiry = rxrpc_soft_ack_delay;
+ unsigned int expiry = rxrpc_soft_ack_delay;
+ ktime_t now, ack_at;
s8 prior = rxrpc_ack_priority[ack_reason];

/* Update DELAY, IDLE, REQUESTED and PING_RESPONSE ACK serial
@@ -111,7 +124,6 @@ static void __rxrpc_propose_ACK(struct rxrpc_call *call, u8 ack_reason,
break;
}

- now = jiffies;
if (test_bit(RXRPC_CALL_EV_ACK, &call->events)) {
_debug("already scheduled");
} else if (immediate || expiry == 0) {
@@ -120,11 +132,11 @@ static void __rxrpc_propose_ACK(struct rxrpc_call *call, u8 ack_reason,
background)
rxrpc_queue_call(call);
} else {
- ack_at = now + expiry;
- _debug("deferred ACK %ld < %ld", expiry, call->ack_at - now);
- if (time_before(ack_at, call->ack_at)) {
+ now = ktime_get_real();
+ ack_at = ktime_add_ms(now, expiry);
+ if (ktime_before(ack_at, call->ack_at)) {
call->ack_at = ack_at;
- rxrpc_set_timer(call, rxrpc_timer_set_for_ack);
+ rxrpc_set_timer(call, rxrpc_timer_set_for_ack, now);
}
}

@@ -157,12 +169,12 @@ static void rxrpc_congestion_timeout(struct rxrpc_call *call)
/*
* Perform retransmission of NAK'd and unack'd packets.
*/
-static void rxrpc_resend(struct rxrpc_call *call)
+static void rxrpc_resend(struct rxrpc_call *call, ktime_t now)
{
struct rxrpc_skb_priv *sp;
struct sk_buff *skb;
rxrpc_seq_t cursor, seq, top;
- ktime_t now = ktime_get_real(), max_age, oldest, resend_at, ack_ts;
+ ktime_t max_age, oldest, ack_ts;
int ix;
u8 annotation, anno_type, retrans = 0, unacked = 0;

@@ -212,14 +224,7 @@ static void rxrpc_resend(struct rxrpc_call *call)
ktime_to_ns(ktime_sub(skb->tstamp, max_age)));
}

- resend_at = ktime_add_ms(oldest, rxrpc_resend_timeout);
- call->resend_at = jiffies +
- nsecs_to_jiffies(ktime_to_ns(ktime_sub(resend_at, now))) +
- 1; /* We have to make sure that the calculated jiffies value
- * falls at or after the nsec value, or we shall loop
- * ceaselessly because the timer times out, but we haven't
- * reached the nsec timeout yet.
- */
+ call->resend_at = ktime_add_ms(oldest, rxrpc_resend_timeout);

if (unacked)
rxrpc_congestion_timeout(call);
@@ -229,7 +234,7 @@ static void rxrpc_resend(struct rxrpc_call *call)
* retransmitting data.
*/
if (!retrans) {
- rxrpc_set_timer(call, rxrpc_timer_set_for_resend);
+ rxrpc_set_timer(call, rxrpc_timer_set_for_resend, now);
spin_unlock_bh(&call->lock);
ack_ts = ktime_sub(now, call->acks_latest_ts);
if (ktime_to_ns(ack_ts) < call->peer->rtt)
@@ -301,7 +306,7 @@ void rxrpc_process_call(struct work_struct *work)
{
struct rxrpc_call *call =
container_of(work, struct rxrpc_call, processor);
- unsigned long now;
+ ktime_t now;

rxrpc_see_call(call);

@@ -320,15 +325,15 @@ recheck_state:
goto out_put;
}

- now = jiffies;
- if (time_after_eq(now, call->expire_at)) {
+ now = ktime_get_real();
+ if (ktime_before(call->expire_at, now)) {
rxrpc_abort_call("EXP", call, 0, RX_CALL_TIMEOUT, ETIME);
set_bit(RXRPC_CALL_EV_ABORT, &call->events);
goto recheck_state;
}

if (test_and_clear_bit(RXRPC_CALL_EV_ACK, &call->events) ||
- time_after_eq(now, call->ack_at)) {
+ ktime_before(call->ack_at, now)) {
call->ack_at = call->expire_at;
if (call->ackr_reason) {
rxrpc_send_call_packet(call, RXRPC_PACKET_TYPE_ACK);
@@ -337,12 +342,12 @@ recheck_state:
}

if (test_and_clear_bit(RXRPC_CALL_EV_RESEND, &call->events) ||
- time_after_eq(now, call->resend_at)) {
- rxrpc_resend(call);
+ ktime_before(call->resend_at, now)) {
+ rxrpc_resend(call, now);
goto recheck_state;
}

- rxrpc_set_timer(call, rxrpc_timer_set_for_resend);
+ rxrpc_set_timer(call, rxrpc_timer_set_for_resend, now);

/* other events may have been raised since we started checking */
if (call->events && call->state < RXRPC_CALL_COMPLETE) {
diff --git a/net/rxrpc/call_object.c b/net/rxrpc/call_object.c
index d4b3293b78fa..456ab752d473 100644
--- a/net/rxrpc/call_object.c
+++ b/net/rxrpc/call_object.c
@@ -19,11 +19,6 @@
#include <net/af_rxrpc.h>
#include "ar-internal.h"

-/*
- * Maximum lifetime of a call (in jiffies).
- */
-unsigned int rxrpc_max_call_lifetime = 60 * HZ;
-
const char *const rxrpc_call_states[NR__RXRPC_CALL_STATES] = {
[RXRPC_CALL_UNINITIALISED] = "Uninit ",
[RXRPC_CALL_CLIENT_AWAIT_CONN] = "ClWtConn",
@@ -77,7 +72,8 @@ static void rxrpc_call_timer_expired(unsigned long _call)
_enter("%d", call->debug_id);

if (call->state < RXRPC_CALL_COMPLETE) {
- trace_rxrpc_timer(call, rxrpc_timer_expired, jiffies);
+ trace_rxrpc_timer(call, rxrpc_timer_expired,
+ ktime_get_real(), jiffies);
rxrpc_queue_call(call);
}
}
@@ -207,14 +203,14 @@ static struct rxrpc_call *rxrpc_alloc_client_call(struct sockaddr_rxrpc *srx,
*/
static void rxrpc_start_call_timer(struct rxrpc_call *call)
{
- unsigned long expire_at;
+ ktime_t now = ktime_get_real(), expire_at;

- expire_at = jiffies + rxrpc_max_call_lifetime;
+ expire_at = ktime_add_ms(now, rxrpc_max_call_lifetime);
call->expire_at = expire_at;
call->ack_at = expire_at;
call->resend_at = expire_at;
- call->timer.expires = expire_at + 1;
- rxrpc_set_timer(call, rxrpc_timer_begin);
+ call->timer.expires = jiffies + LONG_MAX / 2;
+ rxrpc_set_timer(call, rxrpc_timer_begin, now);
}

/*
diff --git a/net/rxrpc/input.c b/net/rxrpc/input.c
index 5ba35b4a907b..3ad9f75031e3 100644
--- a/net/rxrpc/input.c
+++ b/net/rxrpc/input.c
@@ -328,7 +328,8 @@ static bool rxrpc_receiving_reply(struct rxrpc_call *call)
call->resend_at = call->expire_at;
call->ack_at = call->expire_at;
spin_unlock_bh(&call->lock);
- rxrpc_set_timer(call, rxrpc_timer_init_for_reply);
+ rxrpc_set_timer(call, rxrpc_timer_init_for_reply,
+ ktime_get_real());
}

if (!test_bit(RXRPC_CALL_TX_LAST, &call->flags))
diff --git a/net/rxrpc/misc.c b/net/rxrpc/misc.c
index 47dddacdbb91..9d1c721bc4e8 100644
--- a/net/rxrpc/misc.c
+++ b/net/rxrpc/misc.c
@@ -21,28 +21,33 @@
unsigned int rxrpc_max_backlog __read_mostly = 10;

/*
+ * Maximum lifetime of a call (in mx).
+ */
+unsigned int rxrpc_max_call_lifetime = 60 * 1000;
+
+/*
* How long to wait before scheduling ACK generation after seeing a
- * packet with RXRPC_REQUEST_ACK set (in jiffies).
+ * packet with RXRPC_REQUEST_ACK set (in ms).
*/
unsigned int rxrpc_requested_ack_delay = 1;

/*
- * How long to wait before scheduling an ACK with subtype DELAY (in jiffies).
+ * How long to wait before scheduling an ACK with subtype DELAY (in ms).
*
* We use this when we've received new data packets. If those packets aren't
* all consumed within this time we will send a DELAY ACK if an ACK was not
* requested to let the sender know it doesn't need to resend.
*/
-unsigned int rxrpc_soft_ack_delay = 1 * HZ;
+unsigned int rxrpc_soft_ack_delay = 1 * 1000;

/*
- * How long to wait before scheduling an ACK with subtype IDLE (in jiffies).
+ * How long to wait before scheduling an ACK with subtype IDLE (in ms).
*
* We use this when we've consumed some previously soft-ACK'd packets when
* further packets aren't immediately received to decide when to send an IDLE
* ACK let the other end know that it can free up its Tx buffer space.
*/
-unsigned int rxrpc_idle_ack_delay = 0.5 * HZ;
+unsigned int rxrpc_idle_ack_delay = 0.5 * 1000;

/*
* Receive window size in packets. This indicates the maximum number of
diff --git a/net/rxrpc/sendmsg.c b/net/rxrpc/sendmsg.c
index d8dfdce874d8..3322543d460a 100644
--- a/net/rxrpc/sendmsg.c
+++ b/net/rxrpc/sendmsg.c
@@ -149,13 +149,13 @@ static void rxrpc_queue_packet(struct rxrpc_call *call, struct sk_buff *skb,
_debug("need instant resend %d", ret);
rxrpc_instant_resend(call, ix);
} else {
- unsigned long resend_at;
+ ktime_t now = ktime_get_real(), resend_at;

- resend_at = jiffies + msecs_to_jiffies(rxrpc_resend_timeout);
+ resend_at = ktime_add_ms(now, rxrpc_resend_timeout);

- if (time_before(resend_at, call->resend_at)) {
+ if (ktime_before(resend_at, call->resend_at)) {
call->resend_at = resend_at;
- rxrpc_set_timer(call, rxrpc_timer_set_for_send);
+ rxrpc_set_timer(call, rxrpc_timer_set_for_send, now);
}
}

diff --git a/net/rxrpc/sysctl.c b/net/rxrpc/sysctl.c
index 13d1df03ebac..34c706d2f79c 100644
--- a/net/rxrpc/sysctl.c
+++ b/net/rxrpc/sysctl.c
@@ -35,7 +35,7 @@ static struct ctl_table rxrpc_sysctl_table[] = {
.data = &rxrpc_requested_ack_delay,
.maxlen = sizeof(unsigned int),
.mode = 0644,
- .proc_handler = proc_dointvec_ms_jiffies,
+ .proc_handler = proc_dointvec,
.extra1 = (void *)&zero,
},
{
@@ -43,7 +43,7 @@ static struct ctl_table rxrpc_sysctl_table[] = {
.data = &rxrpc_soft_ack_delay,
.maxlen = sizeof(unsigned int),
.mode = 0644,
- .proc_handler = proc_dointvec_ms_jiffies,
+ .proc_handler = proc_dointvec,
.extra1 = (void *)&one,
},
{
@@ -51,7 +51,7 @@ static struct ctl_table rxrpc_sysctl_table[] = {
.data = &rxrpc_idle_ack_delay,
.maxlen = sizeof(unsigned int),
.mode = 0644,
- .proc_handler = proc_dointvec_ms_jiffies,
+ .proc_handler = proc_dointvec,
.extra1 = (void *)&one,
},
{
@@ -85,7 +85,7 @@ static struct ctl_table rxrpc_sysctl_table[] = {
.data = &rxrpc_max_call_lifetime,
.maxlen = sizeof(unsigned int),
.mode = 0644,
- .proc_handler = proc_dointvec_jiffies,
+ .proc_handler = proc_dointvec,
.extra1 = (void *)&one,
},

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