* [PATCH v9 1/5] io-uring: move io_wait_queue definition to header file
2023-02-15 17:44 [PATCH v9 0/5] io_uring: add napi busy polling support Stefan Roesch
@ 2023-02-15 17:44 ` Stefan Roesch
2023-02-15 17:44 ` [PATCH v9 2/5] io-uring: add napi busy poll support Stefan Roesch
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: Stefan Roesch @ 2023-02-15 17:44 UTC (permalink / raw)
To: io-uring, kernel-team; +Cc: shr, axboe, ammarfaizi2
This moves the definition of the io_wait_queue structure to the header
file so it can be also used from other files.
Signed-off-by: Stefan Roesch <[email protected]>
---
io_uring/io_uring.c | 21 ---------------------
io_uring/io_uring.h | 22 ++++++++++++++++++++++
2 files changed, 22 insertions(+), 21 deletions(-)
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index 0e42160a3051..5d6aa783fb97 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -2468,33 +2468,12 @@ int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr)
return ret;
}
-struct io_wait_queue {
- struct wait_queue_entry wq;
- struct io_ring_ctx *ctx;
- unsigned cq_tail;
- unsigned nr_timeouts;
- ktime_t timeout;
-};
-
static inline bool io_has_work(struct io_ring_ctx *ctx)
{
return test_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq) ||
!llist_empty(&ctx->work_llist);
}
-static inline bool io_should_wake(struct io_wait_queue *iowq)
-{
- struct io_ring_ctx *ctx = iowq->ctx;
- int dist = READ_ONCE(ctx->rings->cq.tail) - (int) iowq->cq_tail;
-
- /*
- * Wake up if we have enough events, or if a timeout occurred since we
- * started waiting. For timeouts, we always want to return to userspace,
- * regardless of event count.
- */
- return dist >= 0 || atomic_read(&ctx->cq_timeouts) != iowq->nr_timeouts;
-}
-
static int io_wake_function(struct wait_queue_entry *curr, unsigned int mode,
int wake_flags, void *key)
{
diff --git a/io_uring/io_uring.h b/io_uring/io_uring.h
index 2711865f1e19..021f9af37c74 100644
--- a/io_uring/io_uring.h
+++ b/io_uring/io_uring.h
@@ -27,6 +27,28 @@ enum {
IOU_STOP_MULTISHOT = -ECANCELED,
};
+struct io_wait_queue {
+ struct wait_queue_entry wq;
+ struct io_ring_ctx *ctx;
+ unsigned cq_tail;
+ unsigned nr_timeouts;
+ ktime_t timeout;
+
+};
+
+static inline bool io_should_wake(struct io_wait_queue *iowq)
+{
+ struct io_ring_ctx *ctx = iowq->ctx;
+ int dist = READ_ONCE(ctx->rings->cq.tail) - (int) iowq->cq_tail;
+
+ /*
+ * Wake up if we have enough events, or if a timeout occurred since we
+ * started waiting. For timeouts, we always want to return to userspace,
+ * regardless of event count.
+ */
+ return dist >= 0 || atomic_read(&ctx->cq_timeouts) != iowq->nr_timeouts;
+}
+
struct io_uring_cqe *__io_get_cqe(struct io_ring_ctx *ctx, bool overflow);
bool io_req_cqe_overflow(struct io_kiocb *req);
int io_run_task_work_sig(struct io_ring_ctx *ctx);
--
2.30.2
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH v9 2/5] io-uring: add napi busy poll support
2023-02-15 17:44 [PATCH v9 0/5] io_uring: add napi busy polling support Stefan Roesch
2023-02-15 17:44 ` [PATCH v9 1/5] io-uring: move io_wait_queue definition to header file Stefan Roesch
@ 2023-02-15 17:44 ` Stefan Roesch
2023-02-15 17:44 ` [PATCH v9 3/5] io-uring: add sqpoll support for napi busy poll Stefan Roesch
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: Stefan Roesch @ 2023-02-15 17:44 UTC (permalink / raw)
To: io-uring, kernel-team
Cc: shr, axboe, ammarfaizi2, Olivier Langlois, Jakub Kicinski
This adds the napi busy polling support in io_uring.c. It adds a new
napi_list to the io_ring_ctx structure. This list contains the list of
napi_id's that are currently enabled for busy polling. The list is
synchronized by the new napi_lock spin lock. The current default napi
busy polling time is stored in napi_busy_poll_to. If napi busy polling
is not enabled, the value is 0.
In addition there is also a hash table. The hash table store the napi
id ond the pointer to the above list nodes. The hash table is used to
speed up the lookup to the list elements.
The NAPI_TIMEOUT is stored as a timeout to make sure that the time a
napi entry is stored in the napi list is limited.
The busy poll timeout is also stored as part of the io_wait_queue. This
is necessary as for sq polling the poll interval needs to be adjusted
and the napi callback allows only to pass in one value.
This has been tested with two simple programs from the liburing library
repository: the napi client and the napi server program. The client
sends a request, which has a timestamp in its payload and the server
replies with the same payload. The client calculates the roundtrip time
and stores it to calcualte the results.
The client is running on host1 and the server is running on host 2 (in
the same rack). The measured times below are roundtrip times. They are
average times over 5 runs each. Each run measures 1 million roundtrips.
no rx coal rx coal: frames=88,usecs=33
Default 57us 56us
client_poll=100us 47us 46us
server_poll=100us 51us 46us
client_poll=100us+ 40us 40us
server_poll=100us
client_poll=100us+ 41us 39us
server_poll=100us+
prefer napi busy poll on client
client_poll=100us+ 41us 39us
server_poll=100us+
prefer napi busy poll on server
client_poll=100us+ 41us 39us
server_poll=100us+
prefer napi busy poll on client + server
Signed-off-by: Stefan Roesch <[email protected]>
Suggested-by: Olivier Langlois <[email protected]>
Acked-by: Jakub Kicinski <[email protected]>
---
include/linux/io_uring_types.h | 10 ++
io_uring/Makefile | 1 +
io_uring/io_uring.c | 30 +++-
io_uring/io_uring.h | 4 +
io_uring/napi.c | 243 +++++++++++++++++++++++++++++++++
io_uring/napi.h | 66 +++++++++
io_uring/poll.c | 2 +
7 files changed, 351 insertions(+), 5 deletions(-)
create mode 100644 io_uring/napi.c
create mode 100644 io_uring/napi.h
diff --git a/include/linux/io_uring_types.h b/include/linux/io_uring_types.h
index 0efe4d784358..fe4033aacc4c 100644
--- a/include/linux/io_uring_types.h
+++ b/include/linux/io_uring_types.h
@@ -2,6 +2,7 @@
#define IO_URING_TYPES_H
#include <linux/blkdev.h>
+#include <linux/hashtable.h>
#include <linux/task_work.h>
#include <linux/bitmap.h>
#include <linux/llist.h>
@@ -276,6 +277,15 @@ struct io_ring_ctx {
struct xarray personalities;
u32 pers_next;
+#ifdef CONFIG_NET_RX_BUSY_POLL
+ struct list_head napi_list; /* track busy poll napi_id */
+ spinlock_t napi_lock; /* napi_list lock */
+
+ DECLARE_HASHTABLE(napi_ht, 4);
+ unsigned int napi_busy_poll_to; /* napi busy poll default timeout */
+ bool napi_prefer_busy_poll;
+#endif
+
struct {
/*
* We cache a range of free CQEs we can use, once exhausted it
diff --git a/io_uring/Makefile b/io_uring/Makefile
index 8cc8e5387a75..2efe7c5f07ba 100644
--- a/io_uring/Makefile
+++ b/io_uring/Makefile
@@ -9,3 +9,4 @@ obj-$(CONFIG_IO_URING) += io_uring.o xattr.o nop.o fs.o splice.o \
sqpoll.o fdinfo.o tctx.o poll.o \
cancel.o kbuf.o rsrc.o rw.o opdef.o notif.o
obj-$(CONFIG_IO_WQ) += io-wq.o
+obj-$(CONFIG_NET_RX_BUSY_POLL) += napi.o
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index 5d6aa783fb97..556da2de369f 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -90,6 +90,7 @@
#include "rsrc.h"
#include "cancel.h"
#include "net.h"
+#include "napi.h"
#include "notif.h"
#include "timeout.h"
@@ -335,6 +336,8 @@ static __cold struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p)
INIT_WQ_LIST(&ctx->locked_free_list);
INIT_DELAYED_WORK(&ctx->fallback_work, io_fallback_req_func);
INIT_WQ_LIST(&ctx->submit_state.compl_reqs);
+ io_napi_init(ctx);
+
return ctx;
err:
kfree(ctx->dummy_ubuf);
@@ -2566,15 +2569,31 @@ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events,
iowq.cq_tail = READ_ONCE(ctx->rings->cq.head) + min_events;
iowq.timeout = KTIME_MAX;
- if (uts) {
- struct timespec64 ts;
+ if (!io_napi(ctx)) {
+ if (uts) {
+ struct timespec64 ts;
- if (get_timespec64(&ts, uts))
- return -EFAULT;
- iowq.timeout = ktime_add_ns(timespec64_to_ktime(ts), ktime_get_ns());
+ if (get_timespec64(&ts, uts))
+ return -EFAULT;
+ iowq.timeout = ktime_add_ns(timespec64_to_ktime(ts), ktime_get_ns());
+ }
+ } else {
+ if (uts) {
+ struct timespec64 ts;
+
+ if (get_timespec64(&ts, uts))
+ return -EFAULT;
+
+ io_napi_adjust_timeout(ctx, &iowq, &ts);
+ iowq.timeout = ktime_add_ns(timespec64_to_ktime(ts), ktime_get_ns());
+ } else {
+ io_napi_adjust_timeout(ctx, &iowq, NULL);
+ }
+ io_napi_busy_loop(ctx, &iowq);
}
trace_io_uring_cqring_wait(ctx, min_events);
+
do {
unsigned long check_cq;
@@ -2806,6 +2825,7 @@ static __cold void io_ring_ctx_free(struct io_ring_ctx *ctx)
io_req_caches_free(ctx);
if (ctx->hash_map)
io_wq_put_hash(ctx->hash_map);
+ io_napi_free(ctx);
kfree(ctx->cancel_table.hbs);
kfree(ctx->cancel_table_locked.hbs);
kfree(ctx->dummy_ubuf);
diff --git a/io_uring/io_uring.h b/io_uring/io_uring.h
index 021f9af37c74..2e1b8de8505a 100644
--- a/io_uring/io_uring.h
+++ b/io_uring/io_uring.h
@@ -34,6 +34,10 @@ struct io_wait_queue {
unsigned nr_timeouts;
ktime_t timeout;
+#ifdef CONFIG_NET_RX_BUSY_POLL
+ unsigned int napi_busy_poll_to;
+ bool napi_prefer_busy_poll;
+#endif
};
static inline bool io_should_wake(struct io_wait_queue *iowq)
diff --git a/io_uring/napi.c b/io_uring/napi.c
new file mode 100644
index 000000000000..bb7d2b6b7e90
--- /dev/null
+++ b/io_uring/napi.c
@@ -0,0 +1,243 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include "io_uring.h"
+#include "napi.h"
+
+#ifdef CONFIG_NET_RX_BUSY_POLL
+
+/* Timeout for cleanout of stale entries. */
+#define NAPI_TIMEOUT (60 * SEC_CONVERSION)
+
+struct io_napi_ht_entry {
+ unsigned int napi_id;
+ struct list_head list;
+
+ /* Covered by napi lock spinlock. */
+ unsigned long timeout;
+ struct hlist_node node;
+};
+
+void __io_napi_add(struct io_ring_ctx *ctx, struct file *file)
+{
+ unsigned int napi_id;
+ struct socket *sock;
+ struct sock *sk;
+ struct io_napi_ht_entry *he;
+
+ sock = sock_from_file(file);
+ if (!sock)
+ return;
+
+ sk = sock->sk;
+ if (!sk)
+ return;
+
+ napi_id = READ_ONCE(sk->sk_napi_id);
+
+ /* Non-NAPI IDs can be rejected. */
+ if (napi_id < MIN_NAPI_ID)
+ return;
+
+ spin_lock(&ctx->napi_lock);
+ hash_for_each_possible(ctx->napi_ht, he, node, napi_id) {
+ if (he->napi_id == napi_id) {
+ he->timeout = jiffies + NAPI_TIMEOUT;
+ goto out;
+ }
+ }
+
+ he = kmalloc(sizeof(*he), GFP_NOWAIT);
+ if (!he)
+ goto out;
+
+ he->napi_id = napi_id;
+ he->timeout = jiffies + NAPI_TIMEOUT;
+ hash_add(ctx->napi_ht, &he->node, napi_id);
+
+ list_add_tail(&he->list, &ctx->napi_list);
+
+out:
+ spin_unlock(&ctx->napi_lock);
+}
+
+static inline void adjust_timeout(unsigned int poll_to, struct timespec64 *ts,
+ unsigned int *new_poll_to)
+{
+ struct timespec64 pollto = ns_to_timespec64(1000 * (s64)poll_to);
+
+ if (timespec64_compare(ts, &pollto) > 0) {
+ *ts = timespec64_sub(*ts, pollto);
+ *new_poll_to = poll_to;
+ } else {
+ u64 to = timespec64_to_ns(ts);
+
+ do_div(to, 1000);
+ *new_poll_to = to;
+ ts->tv_sec = 0;
+ ts->tv_nsec = 0;
+ }
+}
+
+static inline bool io_napi_busy_loop_timeout(unsigned long start_time,
+ unsigned long bp_usec)
+{
+ if (bp_usec) {
+ unsigned long end_time = start_time + bp_usec;
+ unsigned long now = busy_loop_current_time();
+
+ return time_after(now, end_time);
+ }
+
+ return true;
+}
+
+static bool io_napi_busy_loop_should_end(void *p, unsigned long start_time)
+{
+ struct io_wait_queue *iowq = p;
+
+ return signal_pending(current) ||
+ io_should_wake(iowq) ||
+ io_napi_busy_loop_timeout(start_time, iowq->napi_busy_poll_to);
+}
+
+static bool __io_napi_busy_loop(struct list_head *napi_list, bool prefer_busy_poll)
+{
+ struct io_napi_ht_entry *e;
+ struct io_napi_ht_entry *n;
+
+ list_for_each_entry_safe(e, n, napi_list, list) {
+ napi_busy_loop(e->napi_id, NULL, NULL, prefer_busy_poll,
+ BUSY_POLL_BUDGET);
+ }
+
+ return !list_empty(napi_list);
+}
+
+static void io_napi_multi_busy_loop(struct list_head *napi_list,
+ struct io_wait_queue *iowq)
+{
+ unsigned long start_time = busy_loop_current_time();
+
+ do {
+ if (list_is_singular(napi_list))
+ break;
+ if (!__io_napi_busy_loop(napi_list, iowq->napi_prefer_busy_poll))
+ break;
+ } while (!io_napi_busy_loop_should_end(iowq, start_time));
+}
+
+static void io_napi_blocking_busy_loop(struct list_head *napi_list,
+ struct io_wait_queue *iowq)
+{
+ if (!list_is_singular(napi_list))
+ io_napi_multi_busy_loop(napi_list, iowq);
+
+ if (list_is_singular(napi_list)) {
+ struct io_napi_ht_entry *ne;
+
+ ne = list_first_entry(napi_list, struct io_napi_ht_entry, list);
+ napi_busy_loop(ne->napi_id, io_napi_busy_loop_should_end, iowq,
+ iowq->napi_prefer_busy_poll, BUSY_POLL_BUDGET);
+ }
+}
+
+static void io_napi_remove_stale(struct io_ring_ctx *ctx)
+{
+ unsigned int i;
+ struct io_napi_ht_entry *he;
+
+ hash_for_each(ctx->napi_ht, i, he, node) {
+ if (time_after(jiffies, he->timeout)) {
+ list_del(&he->list);
+ hash_del(&he->node);
+ }
+ }
+
+}
+
+static void io_napi_merge_lists(struct io_ring_ctx *ctx,
+ struct list_head *napi_list)
+{
+ spin_lock(&ctx->napi_lock);
+ list_splice(napi_list, &ctx->napi_list);
+ io_napi_remove_stale(ctx);
+ spin_unlock(&ctx->napi_lock);
+}
+
+/*
+ * io_napi_init() - Init napi settings
+ * @ctx: pointer to io-uring context structure
+ *
+ * Init napi settings in the io-uring context.
+ */
+void io_napi_init(struct io_ring_ctx *ctx)
+{
+ INIT_LIST_HEAD(&ctx->napi_list);
+ spin_lock_init(&ctx->napi_lock);
+ ctx->napi_prefer_busy_poll = false;
+ ctx->napi_busy_poll_to = READ_ONCE(sysctl_net_busy_poll);
+}
+
+/*
+ * io_napi_free() - Deallocate napi
+ * @ctx: pointer to io-uring context structure
+ *
+ * Free the napi list and the hash table in the io-uring context.
+ */
+void io_napi_free(struct io_ring_ctx *ctx)
+{
+ unsigned int i;
+ struct io_napi_ht_entry *he;
+ LIST_HEAD(napi_list);
+
+ spin_lock(&ctx->napi_lock);
+ hash_for_each(ctx->napi_ht, i, he, node)
+ hash_del(&he->node);
+ spin_unlock(&ctx->napi_lock);
+}
+
+/*
+ * io_napi_adjust_timeout() - Add napi id to the busy poll list
+ * @ctx: pointer to io-uring context structure
+ * @iowq: pointer to io wait queue
+ * @ts: pointer to timespec or NULL
+ *
+ * Adjust the busy loop timeout according to timespec and busy poll timeout.
+ */
+void io_napi_adjust_timeout(struct io_ring_ctx *ctx, struct io_wait_queue *iowq,
+ struct timespec64 *ts)
+{
+ if (ts)
+ adjust_timeout(READ_ONCE(ctx->napi_busy_poll_to), ts,
+ &iowq->napi_busy_poll_to);
+ else
+ iowq->napi_busy_poll_to = READ_ONCE(ctx->napi_busy_poll_to);
+}
+
+/*
+ * io_napi_busy_loop() - execute busy poll loop
+ * @ctx: pointer to io-uring context structure
+ * @iowq: pointer to io wait queue
+ *
+ * Execute the busy poll loop and merge the spliced off list.
+ */
+void io_napi_busy_loop(struct io_ring_ctx *ctx, struct io_wait_queue *iowq)
+{
+ iowq->napi_prefer_busy_poll = READ_ONCE(ctx->napi_prefer_busy_poll);
+
+ /* SQPOLL is handled in sqthread. */
+ if (!(ctx->flags & IORING_SETUP_SQPOLL)) {
+ LIST_HEAD(napi_list);
+
+ spin_lock(&ctx->napi_lock);
+ list_splice_init(&ctx->napi_list, &napi_list);
+ spin_unlock(&ctx->napi_lock);
+
+ if (iowq->napi_busy_poll_to)
+ io_napi_blocking_busy_loop(&napi_list, iowq);
+
+ io_napi_merge_lists(ctx, &napi_list);
+ }
+}
+
+#endif
diff --git a/io_uring/napi.h b/io_uring/napi.h
new file mode 100644
index 000000000000..49322a16b6e5
--- /dev/null
+++ b/io_uring/napi.h
@@ -0,0 +1,66 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef IOU_NAPI_H
+#define IOU_NAPI_H
+
+#include <linux/kernel.h>
+#include <linux/io_uring.h>
+#include <net/busy_poll.h>
+
+#ifdef CONFIG_NET_RX_BUSY_POLL
+
+void io_napi_init(struct io_ring_ctx *ctx);
+void io_napi_free(struct io_ring_ctx *ctx);
+
+void __io_napi_add(struct io_ring_ctx *ctx, struct file *file);
+
+void io_napi_adjust_timeout(struct io_ring_ctx *ctx,
+ struct io_wait_queue *iowq, struct timespec64 *ts);
+void io_napi_busy_loop(struct io_ring_ctx *ctx, struct io_wait_queue *iowq);
+
+static inline bool io_napi(struct io_ring_ctx *ctx)
+{
+ return !list_empty(&ctx->napi_list);
+}
+
+/*
+ * io_napi_add() - Add napi id to the busy poll list
+ * @req: pointer to io_kiocb request
+ *
+ * Add the napi id of the socket to the napi busy poll list and hash table.
+ */
+static inline void io_napi_add(struct io_kiocb *req)
+{
+ struct io_ring_ctx *ctx = req->ctx;
+
+ if (!READ_ONCE(ctx->napi_busy_poll_to))
+ return;
+
+ __io_napi_add(ctx, req->file);
+}
+
+#else
+
+static inline void io_napi_init(struct io_ring_ctx *ctx)
+{
+}
+
+static inline void io_napi_free(struct io_ring_ctx *ctx)
+{
+}
+
+static inline bool io_napi(struct io_ring_ctx *ctx)
+{
+ return false;
+}
+
+static inline void io_napi_add(struct io_kiocb *req)
+{
+}
+
+#define io_napi_adjust_timeout(ctx, iowq, ts) do {} while (0)
+#define io_napi_busy_loop(ctx, iowq) do {} while (0)
+
+#endif
+
+#endif
diff --git a/io_uring/poll.c b/io_uring/poll.c
index 8339a92b4510..ab08299eb341 100644
--- a/io_uring/poll.c
+++ b/io_uring/poll.c
@@ -15,6 +15,7 @@
#include "io_uring.h"
#include "refs.h"
+#include "napi.h"
#include "opdef.h"
#include "kbuf.h"
#include "poll.h"
@@ -629,6 +630,7 @@ static int __io_arm_poll_handler(struct io_kiocb *req,
__io_poll_execute(req, mask);
return 0;
}
+ io_napi_add(req);
if (ipt->owning) {
/*
--
2.30.2
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH v9 3/5] io-uring: add sqpoll support for napi busy poll
2023-02-15 17:44 [PATCH v9 0/5] io_uring: add napi busy polling support Stefan Roesch
2023-02-15 17:44 ` [PATCH v9 1/5] io-uring: move io_wait_queue definition to header file Stefan Roesch
2023-02-15 17:44 ` [PATCH v9 2/5] io-uring: add napi busy poll support Stefan Roesch
@ 2023-02-15 17:44 ` Stefan Roesch
2023-02-15 17:44 ` [PATCH v9 4/5] io_uring: add register/unregister napi function Stefan Roesch
2023-02-15 17:44 ` [PATCH v9 5/5] io_uring: add prefer busy poll to register and unregister napi api Stefan Roesch
4 siblings, 0 replies; 6+ messages in thread
From: Stefan Roesch @ 2023-02-15 17:44 UTC (permalink / raw)
To: io-uring, kernel-team; +Cc: shr, axboe, ammarfaizi2, Olivier Langlois
This adds the sqpoll support to the io-uring napi.
Signed-off-by: Stefan Roesch <[email protected]>
Suggested-by: Olivier Langlois <[email protected]>
---
io_uring/napi.c | 25 +++++++++++++++++++++++++
io_uring/napi.h | 2 ++
io_uring/sqpoll.c | 4 ++++
3 files changed, 31 insertions(+)
diff --git a/io_uring/napi.c b/io_uring/napi.c
index bb7d2b6b7e90..0fbdfe5eea06 100644
--- a/io_uring/napi.c
+++ b/io_uring/napi.c
@@ -240,4 +240,29 @@ void io_napi_busy_loop(struct io_ring_ctx *ctx, struct io_wait_queue *iowq)
}
}
+/*
+ * io_napi_sqpoll_busy_poll() - busy poll loop for sqpoll
+ * @ctx: pointer to io-uring context structure
+ *
+ * Splice of the napi list and execute the napi busy poll loop.
+ */
+int io_napi_sqpoll_busy_poll(struct io_ring_ctx *ctx)
+{
+ int ret = 0;
+ LIST_HEAD(napi_list);
+
+ if (!READ_ONCE(ctx->napi_busy_poll_to))
+ return 0;
+
+ spin_lock(&ctx->napi_lock);
+ list_splice_init(&ctx->napi_list, &napi_list);
+ spin_unlock(&ctx->napi_lock);
+
+ if (__io_napi_busy_loop(&napi_list, ctx->napi_prefer_busy_poll))
+ ret = 1;
+
+ io_napi_merge_lists(ctx, &napi_list);
+ return ret;
+}
+
#endif
diff --git a/io_uring/napi.h b/io_uring/napi.h
index 49322a16b6e5..b3455e52170c 100644
--- a/io_uring/napi.h
+++ b/io_uring/napi.h
@@ -17,6 +17,7 @@ void __io_napi_add(struct io_ring_ctx *ctx, struct file *file);
void io_napi_adjust_timeout(struct io_ring_ctx *ctx,
struct io_wait_queue *iowq, struct timespec64 *ts);
void io_napi_busy_loop(struct io_ring_ctx *ctx, struct io_wait_queue *iowq);
+int io_napi_sqpoll_busy_poll(struct io_ring_ctx *ctx);
static inline bool io_napi(struct io_ring_ctx *ctx)
{
@@ -60,6 +61,7 @@ static inline void io_napi_add(struct io_kiocb *req)
#define io_napi_adjust_timeout(ctx, iowq, ts) do {} while (0)
#define io_napi_busy_loop(ctx, iowq) do {} while (0)
+#define io_napi_sqpoll_busy_poll(ctx) (0)
#endif
diff --git a/io_uring/sqpoll.c b/io_uring/sqpoll.c
index 0119d3f1a556..b8b8cf3b6b02 100644
--- a/io_uring/sqpoll.c
+++ b/io_uring/sqpoll.c
@@ -15,6 +15,7 @@
#include <uapi/linux/io_uring.h>
#include "io_uring.h"
+#include "napi.h"
#include "sqpoll.h"
#define IORING_SQPOLL_CAP_ENTRIES_VALUE 8
@@ -193,6 +194,9 @@ static int __io_sq_thread(struct io_ring_ctx *ctx, bool cap_entries)
ret = io_submit_sqes(ctx, to_submit);
mutex_unlock(&ctx->uring_lock);
+ if (io_napi(ctx))
+ ret += io_napi_sqpoll_busy_poll(ctx);
+
if (to_submit && wq_has_sleeper(&ctx->sqo_sq_wait))
wake_up(&ctx->sqo_sq_wait);
if (creds)
--
2.30.2
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH v9 4/5] io_uring: add register/unregister napi function
2023-02-15 17:44 [PATCH v9 0/5] io_uring: add napi busy polling support Stefan Roesch
` (2 preceding siblings ...)
2023-02-15 17:44 ` [PATCH v9 3/5] io-uring: add sqpoll support for napi busy poll Stefan Roesch
@ 2023-02-15 17:44 ` Stefan Roesch
2023-02-15 17:44 ` [PATCH v9 5/5] io_uring: add prefer busy poll to register and unregister napi api Stefan Roesch
4 siblings, 0 replies; 6+ messages in thread
From: Stefan Roesch @ 2023-02-15 17:44 UTC (permalink / raw)
To: io-uring, kernel-team; +Cc: shr, axboe, ammarfaizi2, Jakub Kicinski
This adds an api to register and unregister the napi for io-uring. If
the arg value is specified when unregistering, the current napi setting
for the busy poll timeout is copied into the user structure. If this is
not required, NULL can be passed as the arg value.
Signed-off-by: Stefan Roesch <[email protected]>
Acked-by: Jakub Kicinski <[email protected]>
---
include/uapi/linux/io_uring.h | 11 ++++++++
io_uring/io_uring.c | 9 +++++++
io_uring/napi.c | 50 +++++++++++++++++++++++++++++++++++
io_uring/napi.h | 13 +++++++++
4 files changed, 83 insertions(+)
diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
index 636a4c2c1294..fe25ae92744d 100644
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h
@@ -518,6 +518,10 @@ enum {
/* register a range of fixed file slots for automatic slot allocation */
IORING_REGISTER_FILE_ALLOC_RANGE = 25,
+ /* set/clear busy poll settings */
+ IORING_REGISTER_NAPI = 26,
+ IORING_UNREGISTER_NAPI = 27,
+
/* this goes last */
IORING_REGISTER_LAST
};
@@ -640,6 +644,13 @@ struct io_uring_buf_reg {
__u64 resv[3];
};
+/* argument for IORING_(UN)REGISTER_NAPI */
+struct io_uring_napi {
+ __u32 busy_poll_to;
+ __u32 pad;
+ __u64 resv;
+};
+
/*
* io_uring_restriction->opcode values
*/
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index 556da2de369f..23d7f1d64b23 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -4291,6 +4291,15 @@ static int __io_uring_register(struct io_ring_ctx *ctx, unsigned opcode,
break;
ret = io_register_file_alloc_range(ctx, arg);
break;
+ case IORING_REGISTER_NAPI:
+ ret = -EINVAL;
+ if (!arg)
+ break;
+ ret = io_register_napi(ctx, arg);
+ break;
+ case IORING_UNREGISTER_NAPI:
+ ret = io_unregister_napi(ctx, arg);
+ break;
default:
ret = -EINVAL;
break;
diff --git a/io_uring/napi.c b/io_uring/napi.c
index 0fbdfe5eea06..56a4754efcfb 100644
--- a/io_uring/napi.c
+++ b/io_uring/napi.c
@@ -196,6 +196,56 @@ void io_napi_free(struct io_ring_ctx *ctx)
spin_unlock(&ctx->napi_lock);
}
+/*
+ * io_napi_register() - Register napi with io-uring
+ * @ctx: pointer to io-uring context structure
+ * @arg: pointer to io_uring_napi structure
+ *
+ * Register napi in the io-uring context.
+ */
+int io_register_napi(struct io_ring_ctx *ctx, void __user *arg)
+{
+ const struct io_uring_napi curr = {
+ .busy_poll_to = ctx->napi_busy_poll_to,
+ };
+ struct io_uring_napi napi;
+
+ if (copy_from_user(&napi, arg, sizeof(napi)))
+ return -EFAULT;
+ if (napi.pad || napi.resv)
+ return -EINVAL;
+
+ WRITE_ONCE(ctx->napi_busy_poll_to, napi.busy_poll_to);
+
+ if (copy_to_user(arg, &curr, sizeof(curr)))
+ return -EFAULT;
+
+ return 0;
+}
+
+/*
+ * io_napi_unregister() - Unregister napi with io-uring
+ * @ctx: pointer to io-uring context structure
+ * @arg: pointer to io_uring_napi structure
+ *
+ * Unregister napi. If arg has been specified copy the busy poll timeout and
+ * prefer busy poll setting to the passed in structure.
+ */
+int io_unregister_napi(struct io_ring_ctx *ctx, void __user *arg)
+{
+ const struct io_uring_napi curr = {
+ .busy_poll_to = ctx->napi_busy_poll_to,
+ };
+
+ if (arg) {
+ if (copy_to_user(arg, &curr, sizeof(curr)))
+ return -EFAULT;
+ }
+
+ WRITE_ONCE(ctx->napi_busy_poll_to, 0);
+ return 0;
+}
+
/*
* io_napi_adjust_timeout() - Add napi id to the busy poll list
* @ctx: pointer to io-uring context structure
diff --git a/io_uring/napi.h b/io_uring/napi.h
index b3455e52170c..8da8f032a441 100644
--- a/io_uring/napi.h
+++ b/io_uring/napi.h
@@ -12,6 +12,9 @@
void io_napi_init(struct io_ring_ctx *ctx);
void io_napi_free(struct io_ring_ctx *ctx);
+int io_register_napi(struct io_ring_ctx *ctx, void __user *arg);
+int io_unregister_napi(struct io_ring_ctx *ctx, void __user *arg);
+
void __io_napi_add(struct io_ring_ctx *ctx, struct file *file);
void io_napi_adjust_timeout(struct io_ring_ctx *ctx,
@@ -50,6 +53,16 @@ static inline void io_napi_free(struct io_ring_ctx *ctx)
{
}
+static inline int io_register_napi(struct io_ring_ctx *ctx, void __user *arg)
+{
+ return -EOPNOTSUPP;
+}
+
+static inline int io_unregister_napi(struct io_ring_ctx *ctx, void __user *arg)
+{
+ return -EOPNOTSUPP;
+}
+
static inline bool io_napi(struct io_ring_ctx *ctx)
{
return false;
--
2.30.2
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH v9 5/5] io_uring: add prefer busy poll to register and unregister napi api
2023-02-15 17:44 [PATCH v9 0/5] io_uring: add napi busy polling support Stefan Roesch
` (3 preceding siblings ...)
2023-02-15 17:44 ` [PATCH v9 4/5] io_uring: add register/unregister napi function Stefan Roesch
@ 2023-02-15 17:44 ` Stefan Roesch
4 siblings, 0 replies; 6+ messages in thread
From: Stefan Roesch @ 2023-02-15 17:44 UTC (permalink / raw)
To: io-uring, kernel-team; +Cc: shr, axboe, ammarfaizi2, Jakub Kicinski
This adds the napi prefer busy poll setting to the register and
unregister napi api. When napi is unregistered and arg is specified,
both napi settings: busy poll timeout and the prefer busy poll setting
are copied into the user structure.
Signed-off-by: Stefan Roesch <[email protected]>
Acked-by: Jakub Kicinski <[email protected]>
---
include/uapi/linux/io_uring.h | 3 ++-
io_uring/napi.c | 6 +++++-
2 files changed, 7 insertions(+), 2 deletions(-)
diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
index fe25ae92744d..e14f31a4b10c 100644
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h
@@ -647,7 +647,8 @@ struct io_uring_buf_reg {
/* argument for IORING_(UN)REGISTER_NAPI */
struct io_uring_napi {
__u32 busy_poll_to;
- __u32 pad;
+ __u8 prefer_busy_poll;
+ __u8 pad[3];
__u64 resv;
};
diff --git a/io_uring/napi.c b/io_uring/napi.c
index 56a4754efcfb..ca12ff5f5611 100644
--- a/io_uring/napi.c
+++ b/io_uring/napi.c
@@ -207,15 +207,17 @@ int io_register_napi(struct io_ring_ctx *ctx, void __user *arg)
{
const struct io_uring_napi curr = {
.busy_poll_to = ctx->napi_busy_poll_to,
+ .prefer_busy_poll = ctx->napi_prefer_busy_poll
};
struct io_uring_napi napi;
if (copy_from_user(&napi, arg, sizeof(napi)))
return -EFAULT;
- if (napi.pad || napi.resv)
+ if (napi.pad[0] || napi.pad[1] || napi.pad[2] || napi.resv)
return -EINVAL;
WRITE_ONCE(ctx->napi_busy_poll_to, napi.busy_poll_to);
+ WRITE_ONCE(ctx->napi_prefer_busy_poll, !!napi.prefer_busy_poll);
if (copy_to_user(arg, &curr, sizeof(curr)))
return -EFAULT;
@@ -235,6 +237,7 @@ int io_unregister_napi(struct io_ring_ctx *ctx, void __user *arg)
{
const struct io_uring_napi curr = {
.busy_poll_to = ctx->napi_busy_poll_to,
+ .prefer_busy_poll = ctx->napi_prefer_busy_poll
};
if (arg) {
@@ -243,6 +246,7 @@ int io_unregister_napi(struct io_ring_ctx *ctx, void __user *arg)
}
WRITE_ONCE(ctx->napi_busy_poll_to, 0);
+ WRITE_ONCE(ctx->napi_prefer_busy_poll, false);
return 0;
}
--
2.30.2
^ permalink raw reply related [flat|nested] 6+ messages in thread