* [PATCH v2 1/2] nvme-tcp: refactor I/O queue setup path
2026-08-24 22:56 [PATCH v2 0/2] nvme-tcp: parallelize I/O queue connect Surabhi Gogte
@ 2026-08-24 22:56 ` Surabhi Gogte
2026-08-24 23:36 ` Randy Jennings
2026-08-24 22:56 ` [PATCH v2 2/2] nvme-tcp: parallelize I/O queue allocation and startup Surabhi Gogte
1 sibling, 1 reply; 5+ messages in thread
From: Surabhi Gogte @ 2026-08-24 22:56 UTC (permalink / raw)
To: Keith Busch, Jens Axboe, Christoph Hellwig, Sagi Grimberg
Cc: linux-nvme, linux-kernel, mkhalfella, randyj, adailey,
Surabhi Gogte
Split the I/O queue setup helpers apart so that the individual steps can
be called directly from nvme_tcp_configure_io_queues():
- Queue count negotiation moves out of nvme_tcp_alloc_io_queues() into a
new nvme_tcp_io_queue_count(), leaving the allocator with just the
per-queue allocation loop.
- TLS PSK validation moves out of __nvme_tcp_alloc_io_queues() into a
new nvme_tcp_tls_check_psk().
- nvme_tcp_configure_io_queues() now calls the three steps directly in
the same order as before.
Signed-off-by: Surabhi Gogte <sgogte@purestorage.com>
---
drivers/nvme/host/tcp.c | 25 +++++++++++++++++++------
1 file changed, 19 insertions(+), 6 deletions(-)
diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c
index 5fda9661bdb7..354668ad29ac 100644
--- a/drivers/nvme/host/tcp.c
+++ b/drivers/nvme/host/tcp.c
@@ -2171,10 +2171,8 @@ static int nvme_tcp_alloc_admin_queue(struct nvme_ctrl *ctrl)
return ret;
}
-static int __nvme_tcp_alloc_io_queues(struct nvme_ctrl *ctrl)
+static int nvme_tcp_tls_check_psk(struct nvme_ctrl *ctrl)
{
- int i, ret;
-
if (nvme_tcp_tls_configured(ctrl)) {
if (ctrl->opts->concat) {
/*
@@ -2196,6 +2194,13 @@ static int __nvme_tcp_alloc_io_queues(struct nvme_ctrl *ctrl)
}
}
+ return 0;
+}
+
+static int __nvme_tcp_alloc_io_queues(struct nvme_ctrl *ctrl)
+{
+ int i, ret;
+
for (i = 1; i < ctrl->queue_count; i++) {
ret = nvme_tcp_alloc_queue(ctrl, i,
ctrl->tls_pskid);
@@ -2212,7 +2217,7 @@ static int __nvme_tcp_alloc_io_queues(struct nvme_ctrl *ctrl)
return ret;
}
-static int nvme_tcp_alloc_io_queues(struct nvme_ctrl *ctrl)
+static int nvme_tcp_io_queue_count(struct nvme_ctrl *ctrl)
{
unsigned int nr_io_queues;
int ret;
@@ -2234,14 +2239,22 @@ static int nvme_tcp_alloc_io_queues(struct nvme_ctrl *ctrl)
nvmf_set_io_queues(ctrl->opts, nr_io_queues,
to_tcp_ctrl(ctrl)->io_queues);
- return __nvme_tcp_alloc_io_queues(ctrl);
+ return 0;
}
static int nvme_tcp_configure_io_queues(struct nvme_ctrl *ctrl, bool new)
{
int ret, nr_queues;
- ret = nvme_tcp_alloc_io_queues(ctrl);
+ ret = nvme_tcp_io_queue_count(ctrl);
+ if (ret)
+ return ret;
+
+ ret = nvme_tcp_tls_check_psk(ctrl);
+ if (ret)
+ return ret;
+
+ ret = __nvme_tcp_alloc_io_queues(ctrl);
if (ret)
return ret;
--
2.55.0
^ permalink raw reply related [flat|nested] 5+ messages in thread* [PATCH v2 2/2] nvme-tcp: parallelize I/O queue allocation and startup
2026-08-24 22:56 [PATCH v2 0/2] nvme-tcp: parallelize I/O queue connect Surabhi Gogte
2026-08-24 22:56 ` [PATCH v2 1/2] nvme-tcp: refactor I/O queue setup path Surabhi Gogte
@ 2026-08-24 22:56 ` Surabhi Gogte
2026-08-24 23:58 ` Randy Jennings
1 sibling, 1 reply; 5+ messages in thread
From: Surabhi Gogte @ 2026-08-24 22:56 UTC (permalink / raw)
To: Keith Busch, Jens Axboe, Christoph Hellwig, Sagi Grimberg
Cc: linux-nvme, linux-kernel, mkhalfella, randyj, adailey,
Surabhi Gogte
Similar to commit 2a8513091d2f ("nvme-rdma: parallelize I/O queue
allocation and startup"), refactor nvme tcp I/O queue setup to use async
API, combining allocation and startup into a single parallel operation
per queue. This reduces connection and reconnection setup time when
there are delays in establishing connections, which is especially
important for high-core-count hosts.
Key changes:
- Use async API to facilitate parallel calls for io queue setup.
- Add nvme_tcp_setup_ctx for propagating errors from async workers.
- Remove nvme_tcp_start_io_queues() and __nvme_tcp_alloc_io_queues();
their logic is folded into nvme_tcp_setup_io_queues() and
nvme_tcp_configure_io_queues().
- Allocate the io tag set before the queues so that the queue range is
known, and only set up the reconnect grow case if the queue count
actually increased.
- Serialize the cpu scan and claim in nvme_tcp_set_queue_io_cpu() with a
spinlock, as concurrent callers would otherwise select the same cpu.
The per-cpu counters no longer need to be atomics.
- Use init_net in nvme_tcp_alloc_queue() instead of the namespace of
current, which is no longer the connecting task once the allocation
runs from a worker. A controller is not guaranteed to be tied to a
namespace, as the reconnect and error recovery paths already run from
a workqueue in init_net.
Testing on a 64-core host with 64 IO-queues shows nvme-tcp connection
time reduced from 61ms to 11ms.
Signed-off-by: Surabhi Gogte <sgogte@purestorage.com>
---
drivers/nvme/host/tcp.c | 126 +++++++++++++++++++++++++---------------
1 file changed, 80 insertions(+), 46 deletions(-)
diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c
index 354668ad29ac..30fe4c5abe0b 100644
--- a/drivers/nvme/host/tcp.c
+++ b/drivers/nvme/host/tcp.c
@@ -7,6 +7,7 @@
#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
+#include <linux/async.h>
#include <linux/err.h>
#include <linux/crc32.h>
#include <linux/nvme-tcp.h>
@@ -54,7 +55,8 @@ MODULE_PARM_DESC(tls_handshake_timeout,
"nvme TLS handshake timeout in seconds (default 10)");
#endif
-static atomic_t nvme_tcp_cpu_queues[NR_CPUS];
+static int nvme_tcp_cpu_queues[NR_CPUS];
+static DEFINE_SPINLOCK(nvme_tcp_cpu_queues_lock);
enum nvme_tcp_send_state {
NVME_TCP_SEND_CMD_PDU = 0,
@@ -154,6 +156,12 @@ struct nvme_tcp_queue {
static DEFINE_MUTEX(nvme_tcp_ctrl_mutex);
static LIST_HEAD_GUARDED(nvme_tcp_ctrl_list, nvme_tcp_ctrl_mutex);
+struct nvme_tcp_setup_ctx {
+ struct nvme_ctrl *ctrl;
+ int qid;
+ int *err;
+};
+
struct nvme_tcp_ctrl {
/* read only in the hot path */
struct nvme_tcp_queue *queues;
@@ -1718,9 +1726,10 @@ static void nvme_tcp_set_queue_io_cpu(struct nvme_tcp_queue *queue)
goto out;
/* Search for the least used cpu from the mq_map */
+ spin_lock(&nvme_tcp_cpu_queues_lock);
io_cpu = WORK_CPU_UNBOUND;
for_each_online_cpu(cpu) {
- int num_queues = atomic_read(&nvme_tcp_cpu_queues[cpu]);
+ int num_queues = nvme_tcp_cpu_queues[cpu];
if (mq_map[cpu] != qid)
continue;
@@ -1731,9 +1740,10 @@ static void nvme_tcp_set_queue_io_cpu(struct nvme_tcp_queue *queue)
}
if (io_cpu != WORK_CPU_UNBOUND) {
queue->io_cpu = io_cpu;
- atomic_inc(&nvme_tcp_cpu_queues[io_cpu]);
+ nvme_tcp_cpu_queues[io_cpu]++;
set_bit(NVME_TCP_Q_IO_CPU_SET, &queue->flags);
}
+ spin_unlock(&nvme_tcp_cpu_queues_lock);
out:
dev_dbg(ctrl->ctrl.device, "queue %d: using cpu %d\n",
qid, queue->io_cpu);
@@ -1846,7 +1856,7 @@ static int nvme_tcp_alloc_queue(struct nvme_ctrl *nctrl, int qid,
queue->cmnd_capsule_len = sizeof(struct nvme_command) +
NVME_TCP_ADMIN_CCSZ;
- ret = sock_create_kern(current->nsproxy->net_ns,
+ ret = sock_create_kern(&init_net,
ctrl->addr.ss_family, SOCK_STREAM,
IPPROTO_TCP, &queue->sock);
if (ret) {
@@ -2010,8 +2020,11 @@ static void nvme_tcp_stop_queue_nowait(struct nvme_ctrl *nctrl, int qid)
if (!test_bit(NVME_TCP_Q_ALLOCATED, &queue->flags))
return;
- if (test_and_clear_bit(NVME_TCP_Q_IO_CPU_SET, &queue->flags))
- atomic_dec(&nvme_tcp_cpu_queues[queue->io_cpu]);
+ if (test_and_clear_bit(NVME_TCP_Q_IO_CPU_SET, &queue->flags)) {
+ spin_lock(&nvme_tcp_cpu_queues_lock);
+ nvme_tcp_cpu_queues[queue->io_cpu]--;
+ spin_unlock(&nvme_tcp_cpu_queues_lock);
+ }
mutex_lock(&queue->queue_lock);
if (test_and_clear_bit(NVME_TCP_Q_LIVE, &queue->flags))
@@ -2118,25 +2131,6 @@ static void nvme_tcp_stop_io_queues(struct nvme_ctrl *ctrl)
nvme_tcp_wait_queue(ctrl, i);
}
-static int nvme_tcp_start_io_queues(struct nvme_ctrl *ctrl,
- int first, int last)
-{
- int i, ret;
-
- for (i = first; i < last; i++) {
- ret = nvme_tcp_start_queue(ctrl, i);
- if (ret)
- goto out_stop_queues;
- }
-
- return 0;
-
-out_stop_queues:
- for (i--; i >= first; i--)
- nvme_tcp_stop_queue(ctrl, i);
- return ret;
-}
-
static int nvme_tcp_alloc_admin_queue(struct nvme_ctrl *ctrl)
{
int ret;
@@ -2197,22 +2191,64 @@ static int nvme_tcp_tls_check_psk(struct nvme_ctrl *ctrl)
return 0;
}
-static int __nvme_tcp_alloc_io_queues(struct nvme_ctrl *ctrl)
+static void nvme_tcp_setup_queue_async(void *data, async_cookie_t cookie)
{
- int i, ret;
+ struct nvme_tcp_setup_ctx *ctx = data;
+ struct nvme_ctrl *ctrl = ctx->ctrl;
+ int ret;
- for (i = 1; i < ctrl->queue_count; i++) {
- ret = nvme_tcp_alloc_queue(ctrl, i,
- ctrl->tls_pskid);
- if (ret)
- goto out_free_queues;
+ ret = nvme_tcp_alloc_queue(ctrl, ctx->qid, ctrl->tls_pskid);
+ if (ret)
+ goto out_err;
+
+ ret = nvme_tcp_start_queue(ctrl, ctx->qid);
+ if (ret)
+ goto out_err;
+
+ return;
+
+out_err:
+ WRITE_ONCE(*ctx->err, ret);
+}
+
+static int nvme_tcp_setup_io_queues(struct nvme_ctrl *ctrl, unsigned int first,
+ unsigned int last)
+{
+ ASYNC_DOMAIN_EXCLUSIVE(queue_domain);
+ struct nvme_tcp_setup_ctx *ctxs;
+ int nr_queues = last - first;
+ int err = 0, i, ret;
+
+ ctxs = kmalloc_objs(*ctxs, nr_queues);
+ if (!ctxs)
+ return -ENOMEM;
+
+ for (i = 0; i < nr_queues; i++) {
+ ctxs[i].ctrl = ctrl;
+ ctxs[i].qid = first + i;
+ ctxs[i].err = &err;
+ async_schedule_domain(nvme_tcp_setup_queue_async, &ctxs[i],
+ &queue_domain);
}
+ async_synchronize_full_domain(&queue_domain);
+ kfree(ctxs);
+
+ ret = READ_ONCE(err);
+ if (ret)
+ goto out_free_queues;
+
return 0;
out_free_queues:
- for (i--; i >= 1; i--)
- nvme_tcp_free_queue(ctrl, i);
+ for (i = first; i < last; i++) {
+ struct nvme_tcp_queue *queue = &to_tcp_ctrl(ctrl)->queues[i];
+
+ if (test_bit(NVME_TCP_Q_LIVE, &queue->flags))
+ nvme_tcp_stop_queue(ctrl, i);
+ if (test_bit(NVME_TCP_Q_ALLOCATED, &queue->flags))
+ nvme_tcp_free_queue(ctrl, i);
+ }
return ret;
}
@@ -2254,10 +2290,6 @@ static int nvme_tcp_configure_io_queues(struct nvme_ctrl *ctrl, bool new)
if (ret)
return ret;
- ret = __nvme_tcp_alloc_io_queues(ctrl);
- if (ret)
- return ret;
-
if (new) {
ret = nvme_alloc_io_tag_set(ctrl, &to_tcp_ctrl(ctrl)->tag_set,
&nvme_tcp_mq_ops,
@@ -2268,12 +2300,12 @@ static int nvme_tcp_configure_io_queues(struct nvme_ctrl *ctrl, bool new)
}
/*
- * Only start IO queues for which we have allocated the tagset
+ * Only setup IO queues for which we have allocated the tagset
* and limited it to the available queues. On reconnects, the
* queue number might have changed.
*/
nr_queues = min(ctrl->tagset->nr_hw_queues + 1, ctrl->queue_count);
- ret = nvme_tcp_start_io_queues(ctrl, 1, nr_queues);
+ ret = nvme_tcp_setup_io_queues(ctrl, 1, nr_queues);
if (ret)
goto out_cleanup_connect_q;
@@ -2297,12 +2329,14 @@ static int nvme_tcp_configure_io_queues(struct nvme_ctrl *ctrl, bool new)
/*
* If the number of queues has increased (reconnect case)
- * start all new queues now.
+ * setup all new queues now.
*/
- ret = nvme_tcp_start_io_queues(ctrl, nr_queues,
- ctrl->tagset->nr_hw_queues + 1);
- if (ret)
- goto out_wait_freeze_timed_out;
+ if (ctrl->tagset->nr_hw_queues + 1 > nr_queues) {
+ ret = nvme_tcp_setup_io_queues(ctrl, nr_queues,
+ ctrl->tagset->nr_hw_queues + 1);
+ if (ret)
+ goto out_wait_freeze_timed_out;
+ }
return 0;
@@ -3140,7 +3174,7 @@ static int __init nvme_tcp_init_module(void)
return -ENOMEM;
for_each_possible_cpu(cpu)
- atomic_set(&nvme_tcp_cpu_queues[cpu], 0);
+ nvme_tcp_cpu_queues[cpu] = 0;
nvmf_register_transport(&nvme_tcp_transport);
return 0;
--
2.55.0
^ permalink raw reply related [flat|nested] 5+ messages in thread