From: Pavel Begunkov <[email protected]>
To: [email protected]
Cc: Jens Axboe <[email protected]>, [email protected]
Subject: [PATCH liburing 1/2] setup: add IORING_SETUP_NO_SQARRAY support
Date: Fri, 29 Sep 2023 13:09:40 +0100 [thread overview]
Message-ID: <2badb194856fad38ef1a9049e4cf121a9516b7f9.1695988793.git.asml.silence@gmail.com> (raw)
In-Reply-To: <[email protected]>
IORING_SETUP_NO_SQARRAY removes sq_array from the kernel, and hence when
set liburing should not try to mmap and initialise it.
Signed-off-by: Pavel Begunkov <[email protected]>
---
src/include/liburing/io_uring.h | 5 +++++
src/setup.c | 14 +++++++++-----
2 files changed, 14 insertions(+), 5 deletions(-)
diff --git a/src/include/liburing/io_uring.h b/src/include/liburing/io_uring.h
index 10a6ef0..793d64f 100644
--- a/src/include/liburing/io_uring.h
+++ b/src/include/liburing/io_uring.h
@@ -185,6 +185,11 @@ enum {
*/
#define IORING_SETUP_REGISTERED_FD_ONLY (1U << 15)
+/*
+ * Removes indirection through the SQ index array.
+ */
+#define IORING_SETUP_NO_SQARRAY (1U << 16)
+
enum io_uring_op {
IORING_OP_NOP,
IORING_OP_READV,
diff --git a/src/setup.c b/src/setup.c
index 2dcb5aa..a0e8296 100644
--- a/src/setup.c
+++ b/src/setup.c
@@ -76,7 +76,8 @@ static void io_uring_setup_ring_pointers(struct io_uring_params *p,
sq->kring_entries = sq->ring_ptr + p->sq_off.ring_entries;
sq->kflags = sq->ring_ptr + p->sq_off.flags;
sq->kdropped = sq->ring_ptr + p->sq_off.dropped;
- sq->array = sq->ring_ptr + p->sq_off.array;
+ if (!(p->flags & IORING_SETUP_NO_SQARRAY))
+ sq->array = sq->ring_ptr + p->sq_off.array;
cq->khead = cq->ring_ptr + p->cq_off.head;
cq->ktail = cq->ring_ptr + p->cq_off.tail;
@@ -220,7 +221,8 @@ static int io_uring_alloc_huge(unsigned entries, struct io_uring_params *p,
ring_mem = cq_entries * sizeof(struct io_uring_cqe);
if (p->flags & IORING_SETUP_CQE32)
ring_mem *= 2;
- ring_mem += sq_entries * sizeof(unsigned);
+ if (!(p->flags & IORING_SETUP_NO_SQARRAY))
+ ring_mem += sq_entries * sizeof(unsigned);
mem_used = sqes_mem + ring_mem;
mem_used = (mem_used + page_size - 1) & ~(page_size - 1);
@@ -335,11 +337,13 @@ static int __io_uring_queue_init_params(unsigned entries, struct io_uring *ring,
/*
* Directly map SQ slots to SQEs
*/
- sq_array = ring->sq.array;
sq_entries = ring->sq.ring_entries;
- for (index = 0; index < sq_entries; index++)
- sq_array[index] = index;
+ if (!(p->flags & IORING_SETUP_NO_SQARRAY)) {
+ sq_array = ring->sq.array;
+ for (index = 0; index < sq_entries; index++)
+ sq_array[index] = index;
+ }
ring->features = p->features;
ring->flags = p->flags;
ring->enter_ring_fd = fd;
--
2.41.0
next prev parent reply other threads:[~2023-09-29 12:19 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-29 12:09 [PATCH liburing 0/2] liburing IORING_SETUP_NO_SQARRAY support Pavel Begunkov
2023-09-29 12:09 ` Pavel Begunkov [this message]
2023-09-29 12:09 ` [PATCH liburing 2/2] setup: default to IORING_SETUP_NO_SQARRAY Pavel Begunkov
2023-10-18 15:40 ` [PATCH liburing 0/2] liburing IORING_SETUP_NO_SQARRAY support Jens Axboe
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