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Message-ID: <20241202143057.378147-31-dhowells@redhat.com>
Date: Mon, 2 Dec 2024 14:30:48 +0000
From: David Howells <dhowells@...hat.com>
To: netdev@...r.kernel.org
Cc: David Howells <dhowells@...hat.com>,
Marc Dionne <marc.dionne@...istor.com>,
Yunsheng Lin <linyunsheng@...wei.com>,
"David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>,
Jakub Kicinski <kuba@...nel.org>,
Paolo Abeni <pabeni@...hat.com>,
linux-afs@...ts.infradead.org,
linux-kernel@...r.kernel.org
Subject: [PATCH net-next 30/37] rxrpc: Don't allocate a txbuf for an ACK transmission
Don't allocate an rxrpc_txbuf struct for an ACK transmission. There's now
no need as the memory to hold the ACK content is allocated with a page frag
allocator. The allocation and freeing of a txbuf is just unnecessary
overhead.
Signed-off-by: David Howells <dhowells@...hat.com>
cc: Marc Dionne <marc.dionne@...istor.com>
cc: "David S. Miller" <davem@...emloft.net>
cc: Eric Dumazet <edumazet@...gle.com>
cc: Jakub Kicinski <kuba@...nel.org>
cc: Paolo Abeni <pabeni@...hat.com>
cc: linux-afs@...ts.infradead.org
cc: netdev@...r.kernel.org
---
include/trace/events/rxrpc.h | 2 -
net/rxrpc/ar-internal.h | 5 +-
net/rxrpc/output.c | 210 ++++++++++++++++++++++-------------
net/rxrpc/txbuf.c | 76 -------------
4 files changed, 131 insertions(+), 162 deletions(-)
diff --git a/include/trace/events/rxrpc.h b/include/trace/events/rxrpc.h
index 7681c67f7d65..326a4c257aea 100644
--- a/include/trace/events/rxrpc.h
+++ b/include/trace/events/rxrpc.h
@@ -462,13 +462,11 @@
/* ---- Must update size of stat_why_req_ack[] if more are added! */
#define rxrpc_txbuf_traces \
- EM(rxrpc_txbuf_alloc_ack, "ALLOC ACK ") \
EM(rxrpc_txbuf_alloc_data, "ALLOC DATA ") \
EM(rxrpc_txbuf_free, "FREE ") \
EM(rxrpc_txbuf_get_buffer, "GET BUFFER ") \
EM(rxrpc_txbuf_get_trans, "GET TRANS ") \
EM(rxrpc_txbuf_get_retrans, "GET RETRANS") \
- EM(rxrpc_txbuf_put_ack_tx, "PUT ACK TX ") \
EM(rxrpc_txbuf_put_cleaned, "PUT CLEANED") \
EM(rxrpc_txbuf_put_nomem, "PUT NOMEM ") \
EM(rxrpc_txbuf_put_rotated, "PUT ROTATED") \
diff --git a/net/rxrpc/ar-internal.h b/net/rxrpc/ar-internal.h
index 361d4f1bfb4f..0a9fad23c9ac 100644
--- a/net/rxrpc/ar-internal.h
+++ b/net/rxrpc/ar-internal.h
@@ -835,11 +835,9 @@ struct rxrpc_txbuf {
#define RXRPC_TXBUF_WIRE_FLAGS 0xff /* The wire protocol flags */
#define RXRPC_TXBUF_RESENT 0x100 /* Set if has been resent */
__be16 cksum; /* Checksum to go in header */
- unsigned short ack_rwind; /* ACK receive window */
- u8 /*enum rxrpc_propose_ack_trace*/ ack_why; /* If ack, why */
bool jumboable; /* Can be non-terminal jumbo subpacket */
u8 nr_kvec; /* Amount of kvec[] used */
- struct kvec kvec[3];
+ struct kvec kvec[1];
};
static inline bool rxrpc_sending_to_server(const struct rxrpc_txbuf *txb)
@@ -1365,7 +1363,6 @@ static inline void rxrpc_sysctl_exit(void) {}
extern atomic_t rxrpc_nr_txbuf;
struct rxrpc_txbuf *rxrpc_alloc_data_txbuf(struct rxrpc_call *call, size_t data_size,
size_t data_align, gfp_t gfp);
-struct rxrpc_txbuf *rxrpc_alloc_ack_txbuf(struct rxrpc_call *call, size_t sack_size);
void rxrpc_get_txbuf(struct rxrpc_txbuf *txb, enum rxrpc_txbuf_trace what);
void rxrpc_see_txbuf(struct rxrpc_txbuf *txb, enum rxrpc_txbuf_trace what);
void rxrpc_put_txbuf(struct rxrpc_txbuf *txb, enum rxrpc_txbuf_trace what);
diff --git a/net/rxrpc/output.c b/net/rxrpc/output.c
index 50798a641e37..73c37689c54f 100644
--- a/net/rxrpc/output.c
+++ b/net/rxrpc/output.c
@@ -71,22 +71,97 @@ static void rxrpc_set_keepalive(struct rxrpc_call *call, ktime_t now)
trace_rxrpc_timer_set(call, delay, rxrpc_timer_trace_keepalive);
}
+/*
+ * Allocate transmission buffers for an ACK and attach them to local->kv[].
+ */
+static int rxrpc_alloc_ack(struct rxrpc_call *call, size_t sack_size)
+{
+ struct rxrpc_wire_header *whdr;
+ struct rxrpc_acktrailer *trailer;
+ struct rxrpc_ackpacket *ack;
+ struct kvec *kv = call->local->kvec;
+ gfp_t gfp = rcu_read_lock_held() ? GFP_ATOMIC | __GFP_NOWARN : GFP_NOFS;
+ void *buf, *buf2 = NULL;
+ u8 *filler;
+
+ buf = page_frag_alloc(&call->local->tx_alloc,
+ sizeof(*whdr) + sizeof(*ack) + 1 + 3 + sizeof(*trailer), gfp);
+ if (!buf)
+ return -ENOMEM;
+
+ if (sack_size) {
+ buf2 = page_frag_alloc(&call->local->tx_alloc, sack_size, gfp);
+ if (!buf2) {
+ page_frag_free(buf);
+ return -ENOMEM;
+ }
+ }
+
+ whdr = buf;
+ ack = buf + sizeof(*whdr);
+ filler = buf + sizeof(*whdr) + sizeof(*ack) + 1;
+ trailer = buf + sizeof(*whdr) + sizeof(*ack) + 1 + 3;
+
+ kv[0].iov_base = whdr;
+ kv[0].iov_len = sizeof(*whdr) + sizeof(*ack);
+ kv[1].iov_base = buf2;
+ kv[1].iov_len = sack_size;
+ kv[2].iov_base = filler;
+ kv[2].iov_len = 3 + sizeof(*trailer);
+ return 3; /* Number of kvec[] used. */
+}
+
+static void rxrpc_free_ack(struct rxrpc_call *call)
+{
+ page_frag_free(call->local->kvec[0].iov_base);
+ if (call->local->kvec[1].iov_base)
+ page_frag_free(call->local->kvec[1].iov_base);
+}
+
+/*
+ * Record the beginning of an RTT probe.
+ */
+static void rxrpc_begin_rtt_probe(struct rxrpc_call *call, rxrpc_serial_t serial,
+ ktime_t now, enum rxrpc_rtt_tx_trace why)
+{
+ unsigned long avail = call->rtt_avail;
+ int rtt_slot = 9;
+
+ if (!(avail & RXRPC_CALL_RTT_AVAIL_MASK))
+ goto no_slot;
+
+ rtt_slot = __ffs(avail & RXRPC_CALL_RTT_AVAIL_MASK);
+ if (!test_and_clear_bit(rtt_slot, &call->rtt_avail))
+ goto no_slot;
+
+ call->rtt_serial[rtt_slot] = serial;
+ call->rtt_sent_at[rtt_slot] = now;
+ smp_wmb(); /* Write data before avail bit */
+ set_bit(rtt_slot + RXRPC_CALL_RTT_PEND_SHIFT, &call->rtt_avail);
+
+ trace_rxrpc_rtt_tx(call, why, rtt_slot, serial);
+ return;
+
+no_slot:
+ trace_rxrpc_rtt_tx(call, rxrpc_rtt_tx_no_slot, rtt_slot, serial);
+}
+
/*
* Fill out an ACK packet.
*/
-static void rxrpc_fill_out_ack(struct rxrpc_call *call,
- struct rxrpc_txbuf *txb,
- u8 ack_reason,
- rxrpc_serial_t serial)
+static int rxrpc_fill_out_ack(struct rxrpc_call *call, int nr_kv, u8 ack_reason,
+ rxrpc_serial_t serial_to_ack, rxrpc_serial_t *_ack_serial)
{
- struct rxrpc_wire_header *whdr = txb->kvec[0].iov_base;
- struct rxrpc_acktrailer *trailer = txb->kvec[2].iov_base + 3;
+ struct kvec *kv = call->local->kvec;
+ struct rxrpc_wire_header *whdr = kv[0].iov_base;
+ struct rxrpc_acktrailer *trailer = kv[2].iov_base + 3;
struct rxrpc_ackpacket *ack = (struct rxrpc_ackpacket *)(whdr + 1);
unsigned int qsize, sack, wrap, to, max_mtu, if_mtu;
rxrpc_seq_t window, wtop;
+ ktime_t now = ktime_get_real();
int rsize;
- u8 *filler = txb->kvec[2].iov_base;
- u8 *sackp = txb->kvec[1].iov_base;
+ u8 *filler = kv[2].iov_base;
+ u8 *sackp = kv[1].iov_base;
rxrpc_inc_stat(call->rxnet, stat_tx_ack_fill);
@@ -94,14 +169,25 @@ static void rxrpc_fill_out_ack(struct rxrpc_call *call,
wtop = call->ackr_wtop;
sack = call->ackr_sack_base % RXRPC_SACK_SIZE;
+ *_ack_serial = rxrpc_get_next_serial(call->conn);
+
+ whdr->epoch = htonl(call->conn->proto.epoch);
+ whdr->cid = htonl(call->cid);
+ whdr->callNumber = htonl(call->call_id);
+ whdr->serial = htonl(*_ack_serial);
whdr->seq = 0;
whdr->type = RXRPC_PACKET_TYPE_ACK;
- txb->flags |= RXRPC_SLOW_START_OK;
+ whdr->flags = call->conn->out_clientflag | RXRPC_SLOW_START_OK;
+ whdr->userStatus = 0;
+ whdr->securityIndex = call->security_ix;
+ whdr->_rsvd = 0;
+ whdr->serviceId = htons(call->dest_srx.srx_service);
+
ack->bufferSpace = 0;
ack->maxSkew = 0;
ack->firstPacket = htonl(window);
ack->previousPacket = htonl(call->rx_highest_seq);
- ack->serial = htonl(serial);
+ ack->serial = htonl(serial_to_ack);
ack->reason = ack_reason;
ack->nAcks = wtop - window;
filler[0] = 0;
@@ -109,12 +195,10 @@ static void rxrpc_fill_out_ack(struct rxrpc_call *call,
filler[2] = 0;
if (ack_reason == RXRPC_ACK_PING)
- txb->flags |= RXRPC_REQUEST_ACK;
+ whdr->flags |= RXRPC_REQUEST_ACK;
if (after(wtop, window)) {
- txb->len += ack->nAcks;
- txb->kvec[1].iov_base = sackp;
- txb->kvec[1].iov_len = ack->nAcks;
+ kv[1].iov_len = ack->nAcks;
wrap = RXRPC_SACK_SIZE - sack;
to = umin(ack->nAcks, RXRPC_SACK_SIZE);
@@ -133,7 +217,6 @@ static void rxrpc_fill_out_ack(struct rxrpc_call *call,
qsize = (window - 1) - call->rx_consumed;
rsize = max_t(int, call->rx_winsize - qsize, 0);
- txb->ack_rwind = rsize;
if_mtu = call->peer->if_mtu - call->peer->hdrsize;
if (call->peer->ackr_adv_pmtud) {
@@ -146,48 +229,27 @@ static void rxrpc_fill_out_ack(struct rxrpc_call *call,
trailer->ifMTU = htonl(if_mtu);
trailer->rwind = htonl(rsize);
trailer->jumbo_max = 0; /* Advertise pmtu discovery */
-}
-
-/*
- * Record the beginning of an RTT probe.
- */
-static void rxrpc_begin_rtt_probe(struct rxrpc_call *call, rxrpc_serial_t serial,
- ktime_t now, enum rxrpc_rtt_tx_trace why)
-{
- unsigned long avail = call->rtt_avail;
- int rtt_slot = 9;
- if (!(avail & RXRPC_CALL_RTT_AVAIL_MASK))
- goto no_slot;
-
- rtt_slot = __ffs(avail & RXRPC_CALL_RTT_AVAIL_MASK);
- if (!test_and_clear_bit(rtt_slot, &call->rtt_avail))
- goto no_slot;
-
- call->rtt_serial[rtt_slot] = serial;
- call->rtt_sent_at[rtt_slot] = now;
- smp_wmb(); /* Write data before avail bit */
- set_bit(rtt_slot + RXRPC_CALL_RTT_PEND_SHIFT, &call->rtt_avail);
-
- trace_rxrpc_rtt_tx(call, why, rtt_slot, serial);
- return;
-
-no_slot:
- trace_rxrpc_rtt_tx(call, rxrpc_rtt_tx_no_slot, rtt_slot, serial);
+ if (ack_reason == RXRPC_ACK_PING)
+ rxrpc_begin_rtt_probe(call, *_ack_serial, now, rxrpc_rtt_tx_ping);
+ if (whdr->flags & RXRPC_REQUEST_ACK)
+ call->peer->rtt_last_req = now;
+ rxrpc_set_keepalive(call, now);
+ return nr_kv;
}
/*
* Transmit an ACK packet.
*/
-static void rxrpc_send_ack_packet(struct rxrpc_call *call, struct rxrpc_txbuf *txb,
- int nr_kv, enum rxrpc_propose_ack_trace why)
+static void rxrpc_send_ack_packet(struct rxrpc_call *call, int nr_kv, size_t len,
+ rxrpc_serial_t serial, enum rxrpc_propose_ack_trace why)
{
struct kvec *kv = call->local->kvec;
struct rxrpc_wire_header *whdr = kv[0].iov_base;
+ struct rxrpc_acktrailer *trailer = kv[2].iov_base + 3;
struct rxrpc_connection *conn;
struct rxrpc_ackpacket *ack = (struct rxrpc_ackpacket *)(whdr + 1);
struct msghdr msg;
- ktime_t now;
int ret;
if (test_bit(RXRPC_CALL_DISCONNECTED, &call->flags))
@@ -201,41 +263,31 @@ static void rxrpc_send_ack_packet(struct rxrpc_call *call, struct rxrpc_txbuf *t
msg.msg_controllen = 0;
msg.msg_flags = MSG_SPLICE_PAGES;
- whdr->flags = txb->flags & RXRPC_TXBUF_WIRE_FLAGS;
-
- txb->serial = rxrpc_get_next_serial(conn);
- whdr->serial = htonl(txb->serial);
- trace_rxrpc_tx_ack(call->debug_id, txb->serial,
+ trace_rxrpc_tx_ack(call->debug_id, serial,
ntohl(ack->firstPacket),
ntohl(ack->serial), ack->reason, ack->nAcks,
- txb->ack_rwind);
+ ntohl(trailer->rwind));
rxrpc_inc_stat(call->rxnet, stat_tx_ack_send);
- iov_iter_kvec(&msg.msg_iter, WRITE, kv, nr_kv, txb->len);
+ iov_iter_kvec(&msg.msg_iter, WRITE, kv, nr_kv, len);
rxrpc_local_dont_fragment(conn->local, why == rxrpc_propose_ack_ping_for_mtu_probe);
- ret = do_udp_sendmsg(conn->local->socket, &msg, txb->len);
+ ret = do_udp_sendmsg(conn->local->socket, &msg, len);
call->peer->last_tx_at = ktime_get_seconds();
if (ret < 0) {
- trace_rxrpc_tx_fail(call->debug_id, txb->serial, ret,
+ trace_rxrpc_tx_fail(call->debug_id, serial, ret,
rxrpc_tx_point_call_ack);
if (why == rxrpc_propose_ack_ping_for_mtu_probe &&
ret == -EMSGSIZE)
- rxrpc_input_probe_for_pmtud(conn, txb->serial, true);
+ rxrpc_input_probe_for_pmtud(conn, serial, true);
} else {
trace_rxrpc_tx_packet(call->debug_id, whdr,
rxrpc_tx_point_call_ack);
- now = ktime_get_real();
- if (ack->reason == RXRPC_ACK_PING)
- rxrpc_begin_rtt_probe(call, txb->serial, now, rxrpc_rtt_tx_ping);
- if (txb->flags & RXRPC_REQUEST_ACK)
- call->peer->rtt_last_req = now;
- rxrpc_set_keepalive(call, now);
if (why == rxrpc_propose_ack_ping_for_mtu_probe) {
call->peer->pmtud_pending = false;
call->peer->pmtud_probing = true;
- call->conn->pmtud_probe = txb->serial;
+ call->conn->pmtud_probe = serial;
call->conn->pmtud_call = call->debug_id;
trace_rxrpc_pmtud_tx(call);
}
@@ -247,10 +299,11 @@ static void rxrpc_send_ack_packet(struct rxrpc_call *call, struct rxrpc_txbuf *t
* Queue an ACK for immediate transmission.
*/
void rxrpc_send_ACK(struct rxrpc_call *call, u8 ack_reason,
- rxrpc_serial_t serial, enum rxrpc_propose_ack_trace why)
+ rxrpc_serial_t serial_to_ack, enum rxrpc_propose_ack_trace why)
{
- struct rxrpc_txbuf *txb;
struct kvec *kv = call->local->kvec;
+ rxrpc_serial_t ack_serial;
+ size_t len;
int nr_kv;
if (test_bit(RXRPC_CALL_DISCONNECTED, &call->flags))
@@ -258,32 +311,29 @@ void rxrpc_send_ACK(struct rxrpc_call *call, u8 ack_reason,
rxrpc_inc_stat(call->rxnet, stat_tx_acks[ack_reason]);
- txb = rxrpc_alloc_ack_txbuf(call, call->ackr_wtop - call->ackr_window);
- if (!txb) {
+ nr_kv = rxrpc_alloc_ack(call, call->ackr_wtop - call->ackr_window);
+ if (nr_kv < 0) {
kleave(" = -ENOMEM");
return;
}
- txb->ack_why = why;
-
- rxrpc_fill_out_ack(call, txb, ack_reason, serial);
+ nr_kv = rxrpc_fill_out_ack(call, nr_kv, ack_reason, serial_to_ack, &ack_serial);
+ len = kv[0].iov_len;
+ len += kv[1].iov_len;
+ len += kv[2].iov_len;
/* Extend a path MTU probe ACK. */
- nr_kv = txb->nr_kvec;
- kv[0] = txb->kvec[0];
- kv[1] = txb->kvec[1];
- kv[2] = txb->kvec[2];
if (why == rxrpc_propose_ack_ping_for_mtu_probe) {
size_t probe_mtu = call->peer->pmtud_trial + sizeof(struct rxrpc_wire_header);
- if (txb->len > probe_mtu)
+ if (len > probe_mtu)
goto skip;
- while (txb->len < probe_mtu) {
- size_t part = umin(probe_mtu - txb->len, PAGE_SIZE);
+ while (len < probe_mtu) {
+ size_t part = umin(probe_mtu - len, PAGE_SIZE);
kv[nr_kv].iov_base = page_address(ZERO_PAGE(0));
kv[nr_kv].iov_len = part;
- txb->len += part;
+ len += part;
nr_kv++;
}
}
@@ -292,10 +342,10 @@ void rxrpc_send_ACK(struct rxrpc_call *call, u8 ack_reason,
atomic_set(&call->ackr_nr_consumed, 0);
clear_bit(RXRPC_CALL_RX_IS_IDLE, &call->flags);
- trace_rxrpc_send_ack(call, why, ack_reason, serial);
- rxrpc_send_ack_packet(call, txb, nr_kv, why);
+ trace_rxrpc_send_ack(call, why, ack_reason, ack_serial);
+ rxrpc_send_ack_packet(call, nr_kv, len, ack_serial, why);
skip:
- rxrpc_put_txbuf(txb, rxrpc_txbuf_put_ack_tx);
+ rxrpc_free_ack(call);
}
/*
diff --git a/net/rxrpc/txbuf.c b/net/rxrpc/txbuf.c
index 067223c8c35f..131d9e55c8e9 100644
--- a/net/rxrpc/txbuf.c
+++ b/net/rxrpc/txbuf.c
@@ -73,82 +73,6 @@ struct rxrpc_txbuf *rxrpc_alloc_data_txbuf(struct rxrpc_call *call, size_t data_
return txb;
}
-/*
- * Allocate and partially initialise an ACK packet.
- */
-struct rxrpc_txbuf *rxrpc_alloc_ack_txbuf(struct rxrpc_call *call, size_t sack_size)
-{
- struct rxrpc_wire_header *whdr;
- struct rxrpc_acktrailer *trailer;
- struct rxrpc_ackpacket *ack;
- struct rxrpc_txbuf *txb;
- gfp_t gfp = rcu_read_lock_held() ? GFP_ATOMIC | __GFP_NOWARN : GFP_NOFS;
- void *buf, *buf2 = NULL;
- u8 *filler;
-
- txb = kmalloc(sizeof(*txb), gfp);
- if (!txb)
- return NULL;
-
- buf = page_frag_alloc(&call->local->tx_alloc,
- sizeof(*whdr) + sizeof(*ack) + 1 + 3 + sizeof(*trailer), gfp);
- if (!buf) {
- kfree(txb);
- return NULL;
- }
-
- if (sack_size) {
- buf2 = page_frag_alloc(&call->local->tx_alloc, sack_size, gfp);
- if (!buf2) {
- page_frag_free(buf);
- kfree(txb);
- return NULL;
- }
- }
-
- whdr = buf;
- ack = buf + sizeof(*whdr);
- filler = buf + sizeof(*whdr) + sizeof(*ack) + 1;
- trailer = buf + sizeof(*whdr) + sizeof(*ack) + 1 + 3;
-
- refcount_set(&txb->ref, 1);
- txb->call_debug_id = call->debug_id;
- txb->debug_id = atomic_inc_return(&rxrpc_txbuf_debug_ids);
- txb->space = 0;
- txb->len = sizeof(*whdr) + sizeof(*ack) + 3 + sizeof(*trailer);
- txb->offset = 0;
- txb->flags = call->conn->out_clientflag;
- txb->ack_rwind = 0;
- txb->seq = 0;
- txb->serial = 0;
- txb->cksum = 0;
- txb->nr_kvec = 3;
- txb->kvec[0].iov_base = whdr;
- txb->kvec[0].iov_len = sizeof(*whdr) + sizeof(*ack);
- txb->kvec[1].iov_base = buf2;
- txb->kvec[1].iov_len = sack_size;
- txb->kvec[2].iov_base = filler;
- txb->kvec[2].iov_len = 3 + sizeof(*trailer);
-
- whdr->epoch = htonl(call->conn->proto.epoch);
- whdr->cid = htonl(call->cid);
- whdr->callNumber = htonl(call->call_id);
- whdr->seq = 0;
- whdr->type = RXRPC_PACKET_TYPE_ACK;
- whdr->flags = 0;
- whdr->userStatus = 0;
- whdr->securityIndex = call->security_ix;
- whdr->_rsvd = 0;
- whdr->serviceId = htons(call->dest_srx.srx_service);
-
- get_page(virt_to_head_page(trailer));
-
- trace_rxrpc_txbuf(txb->debug_id, txb->call_debug_id, txb->seq, 1,
- rxrpc_txbuf_alloc_ack);
- atomic_inc(&rxrpc_nr_txbuf);
- return txb;
-}
-
void rxrpc_get_txbuf(struct rxrpc_txbuf *txb, enum rxrpc_txbuf_trace what)
{
int r;
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